Properties and Materials

**3**

**Chapter 1**

**Abstract**

Two Spectroscopies as Main

In the recent years the synthesis and characterization of nanomaterials has been one of the most efficacious way to produce new materials with improved or completely new properties. The polymer-clay nanocomposites are one of the most interesting nanomaterials with the possibility to create a myriad of new materials with many applications. Lamellar materials are classified as two-dimensional (2D), because there are formed by platelets piled up in one crystallographic direction, as the graphite and clays. The synthesis of controlled dimensional nanostructures as well as the characterization of the intrinsic and potentially peculiar properties of these nanostructures are central themes in nanoscience. The study of different nanostructures has great potential to test and understand fundamental concepts about the role of particle dimensionality on their physicochemical properties. Among the various materials studied in the literature, undoubtedly, polymer-clay materials, especially conducting polymers with smectite clays, such as montmorillonites (MMT) are of particular note. Our group have paid many efforts in the characterization of nanomaterials by using powerful spectroscopic techniques to study both the guest and host in case of inclusion compounds, nanofibers, carbon allotropes or many phases present in polymer-clay nanocomposites. There are two central questions that it was possible to address in this study: (i) the molecular structure of the polymer is drastically changed inside the interlayer cavity of clay and (ii) by using the appropriate synthetic or heating route is possible to change the molecular structure of the confined polymer. In the follow lines, it is briefly told the main aspects of resonance Raman and X-ray absorption spectroscopies in the study

Probably the clay is one of the most ancient and important material used and transformed by the humankind in order to produce a myriad of objects with many purposes. In fact, the historical impact of clay can be weighted by their intense use in many passages of one of the most influential book, the biblical text, as a synonym

Source for Investigation of

Polymer-Clay Materials

*Gustavo Morari do Nascimento*

of polymer-clay nanocomposites.

**1. Introduction**

**1.1 Clay science**

**Keywords:** clay, nanocomposites, raman, XANES

of a material that can be forged and transformed, as follows:

### **Chapter 1**

## Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials

*Gustavo Morari do Nascimento*

### **Abstract**

In the recent years the synthesis and characterization of nanomaterials has been one of the most efficacious way to produce new materials with improved or completely new properties. The polymer-clay nanocomposites are one of the most interesting nanomaterials with the possibility to create a myriad of new materials with many applications. Lamellar materials are classified as two-dimensional (2D), because there are formed by platelets piled up in one crystallographic direction, as the graphite and clays. The synthesis of controlled dimensional nanostructures as well as the characterization of the intrinsic and potentially peculiar properties of these nanostructures are central themes in nanoscience. The study of different nanostructures has great potential to test and understand fundamental concepts about the role of particle dimensionality on their physicochemical properties. Among the various materials studied in the literature, undoubtedly, polymer-clay materials, especially conducting polymers with smectite clays, such as montmorillonites (MMT) are of particular note. Our group have paid many efforts in the characterization of nanomaterials by using powerful spectroscopic techniques to study both the guest and host in case of inclusion compounds, nanofibers, carbon allotropes or many phases present in polymer-clay nanocomposites. There are two central questions that it was possible to address in this study: (i) the molecular structure of the polymer is drastically changed inside the interlayer cavity of clay and (ii) by using the appropriate synthetic or heating route is possible to change the molecular structure of the confined polymer. In the follow lines, it is briefly told the main aspects of resonance Raman and X-ray absorption spectroscopies in the study of polymer-clay nanocomposites.

### **Keywords:** clay, nanocomposites, raman, XANES

### **1. Introduction**

### **1.1 Clay science**

Probably the clay is one of the most ancient and important material used and transformed by the humankind in order to produce a myriad of objects with many purposes. In fact, the historical impact of clay can be weighted by their intense use in many passages of one of the most influential book, the biblical text, as a synonym of a material that can be forged and transformed, as follows:

"Then the Lord God formed the man of dust from the ground and breathed into his nostrils the breath of life, and the man became a living creature." Genesis 2: 7 [1].

"But now, O Lord, you are our Father; we are the clay, and you are our potter; we are all the work of your hand." Isaiah 64: 8 [1].

In fact, farmers to produce plants explore the mechanical and chemical environment of clays, ceramists and artists continuously use clays to create extraordinary objects. To the editor, give softness to the paper surface in high quality prints. In medical area may be a relief for diarrhea and so on. In fact, there is no uniform nomenclature for clay and clay materials [2–4]. Clay material is "…a naturally occurring material composed primarily of fine-grained minerals, which is generally plastic at appropriate water contents and will harden with dried or fired". Naturally, this definition is elastic, because in geology science is considered clay the particles with size dimension of less than <4 μm, while in colloid science the value <1 μm is more acceptable [5]. The term clay mineral signifies a class of "…phyllosilicate minerals and minerals which impart plasticity to clay and which harden upon drying or firing" [6]. Since the origin of the mineral is not part of the definition, clay mineral (unlike clay) may be synthetic.

Hence, clay minerals have layers ordered in nanoscale and many different components can be present, as consequence, only by using advanced spectroscopic techniques it is possible to study their structures in detail. X-ray diffraction techniques are applied to determine the crystalline phases and basal distances *d*001. The *d*<sup>001</sup> is an important parameter to follow in the intercalation process. Clays layers have structures builded from tetrahedral sheets in which a silicon atom is surrounded by four oxygen atoms and octahedral sheets in which a metal like aluminum or magnesium is surrounded by eight oxygen atoms [7–10]. The tetrahedral (T) and octahedral (O) sheets are bonded by the oxygen atoms. Unshared oxygen atoms are present in hydroxyl form (see **Figure 1**). Two main arrangements of T and O layers can be observed in the structures of clays. One tetrahedral fused to one octahedral (1:1) is called as kaolin group with the general composition of Al2Si2O5(OH)5 and the layer thickness of ~0.7 nm. The crystal lattice consisted of one octahedral sheet

**5**

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials*

sandwiched between two tetrahedral sheets (2:1) with the total thickness of 0.94 nm is well known as phyllosilicates. The 2:1 phyllosilicates those are electrostatically neutral with no inter layer ion and no expansion in water are known as pyrophyllite. However, when silicon in T sheets is substituted by aluminum, the 2:1 structure is called mica. The negative charge induced by this change is balanced by the introduction of potassium cations between the layers. Potassium cation has similar size of the hole created by Si/Al in tetrahedral sheets. Consequently, the 2:1 layers are held together strongly and the swelling or exfoliation of layers is not possible. The

aluminum cations in the O layers can be partially substituted by divalent magnesium or iron cations in neutral pyrophyllite and as result the smectite clay group is formed, whose structure consists of a central sheet containing groups MO4(OH)2 of octahedral symmetry associated with two tetrahedral sheets (MO4) producing layers designated T:O:T (see **Figure 1**). The O sites are occupied by ions of aluminum, iron and/or magnesium, while the centers accommodate tetrahedrons of silicon and

In the last decades, the synthesis and characterization of nanomaterials and nanocomposites with improved or new properties has made the possibility of producing intelligent materials real [11]. One group of interesting nanomaterials with the possibility to create a myriad of new materials with many applications is the polymer-clay nanocomposites. Lamellar materials are classified as two-dimensional (2D), because there are formed by platelets piled up in one crystallographic direction, as the graphite and clays [12, 13]. The synthesis of controlled dimensional nanostructures as well as the characterization of the intrinsic and potentially peculiar properties of these nanostructures are central themes in nanoscience [14]. The study of different nanostructures has great potential to test and understand fundamental concepts about the role of particle dimensionality on their physicochemical properties. Among the various materials studied in the literature, undoubtedly, polymer-clay materials, especially conducting polymers with smectite clays, such as

Our group have paid many efforts in the characterization of nanomaterials by using powerful spectroscopic techniques to study both the guest and host in case of inclusion compounds, [26] nanofibers, [27–29] carbon allotropes [30–38] or many phases present in polymer-clay nanocomposites [15–25]. In this brief chapter, we give an overview of some contribution of our studies of polymer-clay nanocomposites by using resonance Raman and X-ray absorption spectroscopies as main techniques of investigation. There are two central questions that was possible to address in our studies: (i) the molecular structure of the polymer is drastically changed inside the interlayer cavity of clay and (ii) by using the appropriate synthetic or heating route is possible to change the molecular structure of the confined polymer.

Since the foundation of modern basis of physical sciences in the end of XIX century, the spectroscopies are essential to the investigation of the structure of the matter. The molecular spectroscopy are grounded in the studies of the transitions between the vibrational and/or rotational levels. Among the techniques that can be used to study the molecular structure, infrared and Raman spectroscopies are in a pivotal position. By using these techniques was possible the determination of structures from dyes [39], metallic complexes [40–42], conducting polymers [43, 44], polymer-clay nanocomposites [15–25] to carbon allotropes [30–38]. In Raman spectroscopy, [45–47] the physical phenomenon is very distinct from the infrared, which is a typical absorption

montmorillonites (MMT) are of particular note [15–25].

*DOI: http://dx.doi.org/10.5772/intechopen.95825*

aluminum ions.

**1.2 Techniques**

*1.2.1 Resonance Raman spectroscopy*

**Figure 1.** *Schematic representation of T:O:T structure of Smectite clay group.*

### *Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials DOI: http://dx.doi.org/10.5772/intechopen.95825*

sandwiched between two tetrahedral sheets (2:1) with the total thickness of 0.94 nm is well known as phyllosilicates. The 2:1 phyllosilicates those are electrostatically neutral with no inter layer ion and no expansion in water are known as pyrophyllite. However, when silicon in T sheets is substituted by aluminum, the 2:1 structure is called mica. The negative charge induced by this change is balanced by the introduction of potassium cations between the layers. Potassium cation has similar size of the hole created by Si/Al in tetrahedral sheets. Consequently, the 2:1 layers are held together strongly and the swelling or exfoliation of layers is not possible. The aluminum cations in the O layers can be partially substituted by divalent magnesium or iron cations in neutral pyrophyllite and as result the smectite clay group is formed, whose structure consists of a central sheet containing groups MO4(OH)2 of octahedral symmetry associated with two tetrahedral sheets (MO4) producing layers designated T:O:T (see **Figure 1**). The O sites are occupied by ions of aluminum, iron and/or magnesium, while the centers accommodate tetrahedrons of silicon and aluminum ions.

In the last decades, the synthesis and characterization of nanomaterials and nanocomposites with improved or new properties has made the possibility of producing intelligent materials real [11]. One group of interesting nanomaterials with the possibility to create a myriad of new materials with many applications is the polymer-clay nanocomposites. Lamellar materials are classified as two-dimensional (2D), because there are formed by platelets piled up in one crystallographic direction, as the graphite and clays [12, 13]. The synthesis of controlled dimensional nanostructures as well as the characterization of the intrinsic and potentially peculiar properties of these nanostructures are central themes in nanoscience [14]. The study of different nanostructures has great potential to test and understand fundamental concepts about the role of particle dimensionality on their physicochemical properties. Among the various materials studied in the literature, undoubtedly, polymer-clay materials, especially conducting polymers with smectite clays, such as montmorillonites (MMT) are of particular note [15–25].

Our group have paid many efforts in the characterization of nanomaterials by using powerful spectroscopic techniques to study both the guest and host in case of inclusion compounds, [26] nanofibers, [27–29] carbon allotropes [30–38] or many phases present in polymer-clay nanocomposites [15–25]. In this brief chapter, we give an overview of some contribution of our studies of polymer-clay nanocomposites by using resonance Raman and X-ray absorption spectroscopies as main techniques of investigation. There are two central questions that was possible to address in our studies: (i) the molecular structure of the polymer is drastically changed inside the interlayer cavity of clay and (ii) by using the appropriate synthetic or heating route is possible to change the molecular structure of the confined polymer.

### **1.2 Techniques**

### *1.2.1 Resonance Raman spectroscopy*

Since the foundation of modern basis of physical sciences in the end of XIX century, the spectroscopies are essential to the investigation of the structure of the matter. The molecular spectroscopy are grounded in the studies of the transitions between the vibrational and/or rotational levels. Among the techniques that can be used to study the molecular structure, infrared and Raman spectroscopies are in a pivotal position. By using these techniques was possible the determination of structures from dyes [39], metallic complexes [40–42], conducting polymers [43, 44], polymer-clay nanocomposites [15–25] to carbon allotropes [30–38]. In Raman spectroscopy, [45–47] the physical phenomenon is very distinct from the infrared, which is a typical absorption

between allowed states, in the case of Raman; there is a scattering process of the incident radiation. The radiation source has much more energy than the vibrational transitions, but through the scattering process, it is possible to screen the vibrational levels (see **Figure 2**).

Another possibility in Raman spectroscopy is the use of different laser lines ( *E*<sup>0</sup> ), as consequence there is the chance to probe electronic levels in addition to the vibrational ones. When the *E*0 is equal or near to an electronic transition there is an increase of the Raman cross-section for at least 105 times and also the intensification of the vibrational modes associated to the chromophore structure. The use of microscopies coupled to the Raman instrument permits the investigation of the sample at microscopic level (or nanoscopic level if an electronic or probe microscopies were used) in a non-destructive manner. The main advantage however is the ability to focus the laser on a very small part of the sample (1 μm approximately or smaller). The high lateral resolution and depth of field (the order of a few micrometers) are very useful for the study of multilayered polymeric thin films or others complex materials, such as polymer-clay nanocomposites. In fact, the major part of our studies were conducted in a Raman instrument coupled with an optical microscopy.

### *1.2.2 X-ray absorption spectroscopy*

There are many spectroscopic techniques employed routinely in clay science research in order to investigate multiple aspects of the samples. X-ray spectroscopy has a unique capability to obtain atom-specific information just by tune the correct incident energy of a synchrotron radiation ring. Hence, it is possible to study different atoms and their environments in a clay material or any other complex sample. An X-ray absorption spectrum (XAS) is a consequence of the excitations of a core electron to molecular unoccupied states (or extended states in a case of solid

**7**

**Figure 3.**

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials*

samples). For instance, in **Figure 3** is schematically represented the absorption of an N K shell electrons (1 s level) of an atom bonded in a solid material. The absorption occurs if the incident photon energy is transferred to an electron strongly bounded to the atom with sudden changes in the absorption coefficient. The X-ray absorption spectra can be also used for analytical purposes, because the energy

*3.000 and the spectra were recorded in the total electron yield (TEY) with the sample compartment pressure of 10−6 Pa. The TEY detection can be briefly described as follows: I(replacement current of electrons)* ∝ *I(emitted* 

*a) the N K XANES measurements are done in ultrahigh vacuum (the pressure inside the chamber is ca. 10−7 mbar). The measured signal is the current of reposition of electrons from the sample (near 10−12 a), after the X-ray absorption there are many emission effects (photoelectrons, electrons auger and secondary electrons) those are proportional to the absorption intensity [25]. The arrangement used in our experiments is displayed above. A* 

*the measurements are made with the rod positioned vertically in the sample chamber. b) Schematic representation of the transitions from 1 s to* π*\* and* σ*\* states of a molecular material (PANI-EB), an the correspondent N K-edge X-ray absorption spectrum is also displayed. c) N K XANES spectrum of powered sample of PANI-EB is represented by the black top continuous line (—). The five Voigt bands used in the deconvolution of the experimental spectrum are shown below the experimental data (red dashed lines,* − *– –). The sum spectrum of the five Voigt bands is also displayed (red pointed line, · · ·). Scheme of PANI-EB is also shown at the top of the figure; the main peaks assigned to 1 s* → π*\* transitions are also indicated. Deconvolution of the experimental N K XANES spectrum was done using the (SPSS, 1995) with Voigt bands (Voigt area mode with varying widths) and linear baseline (linear, D2 mode). N K XANES spectrum was obtained in a spherical grating Monochromator (SGM) beam line (dipole magnetic field of 1.65 T and critical energy of 2.08 keV) at the Brazilian National Synchrotron Light Laboratory (LNLS, electron energy of the storage ring of 1.37 GeV). This line can operate in the energy range from 250 eV to 1000 eV, which covers the K edges of carbon (277 eV), nitrogen (392.4 eV), and oxygen (524.9 eV).* 

*) and prevent the mixing of the samples, since* 

 *spot size with spectral resolution E/*Δ*E better than* 

Our group has been used X-ray spectroscopy to investigated different conjugated systems, [16, 17, 23, 25] such as polymers and dyes and their nanocomposites with clays and other materials. The N K-edge XANES spectrum of PANI in its emeraldine base form (EB) is dominated by 1 s → π\* transitions whose energy values and intensities are related to the oxidation and doping states of PANI (see **Figure 3**). The use of multiple edges permit to probe the polymer or the clay structures such as in

Our group have been studied conducting polymer-clay nanocomposites a more than a decade; the main reason is to correlate the electrical and thermal properties

edges are characteristic of each chemical element [48–50].

*grooved rod is placed over the main rod to delimit the area (ca. 0.2 cm2*

*The SGM beam line has a focused beam of roughly a 0.5 mm2*

*electrons)* ∝ *I(absorbed electrons).*

the case of polymer-clay nanocomposites.

**2. Example of recent investigated system**

**2.1 Polyaniline-clay materials under heating**

*DOI: http://dx.doi.org/10.5772/intechopen.95825*

**Figure 2.**

*Schematic representation of Raman and IR phenomenon.*

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials DOI: http://dx.doi.org/10.5772/intechopen.95825*

### **Figure 3.**

*a) the N K XANES measurements are done in ultrahigh vacuum (the pressure inside the chamber is ca. 10−7 mbar). The measured signal is the current of reposition of electrons from the sample (near 10−12 a), after the X-ray absorption there are many emission effects (photoelectrons, electrons auger and secondary electrons) those are proportional to the absorption intensity [25]. The arrangement used in our experiments is displayed above. A grooved rod is placed over the main rod to delimit the area (ca. 0.2 cm2 ) and prevent the mixing of the samples, since the measurements are made with the rod positioned vertically in the sample chamber. b) Schematic representation of the transitions from 1 s to* π*\* and* σ*\* states of a molecular material (PANI-EB), an the correspondent N K-edge X-ray absorption spectrum is also displayed. c) N K XANES spectrum of powered sample of PANI-EB is represented by the black top continuous line (—). The five Voigt bands used in the deconvolution of the experimental spectrum are shown below the experimental data (red dashed lines,* − *– –). The sum spectrum of the five Voigt bands is also displayed (red pointed line, · · ·). Scheme of PANI-EB is also shown at the top of the figure; the main peaks assigned to 1 s* → π*\* transitions are also indicated. Deconvolution of the experimental N K XANES spectrum was done using the (SPSS, 1995) with Voigt bands (Voigt area mode with varying widths) and linear baseline (linear, D2 mode). N K XANES spectrum was obtained in a spherical grating Monochromator (SGM) beam line (dipole magnetic field of 1.65 T and critical energy of 2.08 keV) at the Brazilian National Synchrotron Light Laboratory (LNLS, electron energy of the storage ring of 1.37 GeV). This line can operate in the energy range from 250 eV to 1000 eV, which covers the K edges of carbon (277 eV), nitrogen (392.4 eV), and oxygen (524.9 eV). The SGM beam line has a focused beam of roughly a 0.5 mm2 spot size with spectral resolution E/*Δ*E better than 3.000 and the spectra were recorded in the total electron yield (TEY) with the sample compartment pressure of 10−6 Pa. The TEY detection can be briefly described as follows: I(replacement current of electrons)* ∝ *I(emitted electrons)* ∝ *I(absorbed electrons).*

samples). For instance, in **Figure 3** is schematically represented the absorption of an N K shell electrons (1 s level) of an atom bonded in a solid material. The absorption occurs if the incident photon energy is transferred to an electron strongly bounded to the atom with sudden changes in the absorption coefficient. The X-ray absorption spectra can be also used for analytical purposes, because the energy edges are characteristic of each chemical element [48–50].

Our group has been used X-ray spectroscopy to investigated different conjugated systems, [16, 17, 23, 25] such as polymers and dyes and their nanocomposites with clays and other materials. The N K-edge XANES spectrum of PANI in its emeraldine base form (EB) is dominated by 1 s → π\* transitions whose energy values and intensities are related to the oxidation and doping states of PANI (see **Figure 3**). The use of multiple edges permit to probe the polymer or the clay structures such as in the case of polymer-clay nanocomposites.

### **2. Example of recent investigated system**

### **2.1 Polyaniline-clay materials under heating**

Our group have been studied conducting polymer-clay nanocomposites a more than a decade; the main reason is to correlate the electrical and thermal properties of the material with the structural backbone and molecular arrangements of the interlayer polymer. The bulk properties of a conjugated polymer is correlated to the arrangement of its chains [51–53]. By intercalation into clays, it is possible to increase the polymer properties by changing its molecular arranging, but there is also an improvement of properties by interaction with the clay layers. The all reasons for the polymer-clay synergism is not yet completely understood, however many data was acquired in the literature for many polymer layered materials [54–56]. Nanocomposites formed with inorganic host structures and polyaniline and its derivatives have been one of the most studied systems. Among the inorganic hosts employed to confine conducting polymers, clays are frequently used. Our group, have been dedicate much effort to study such system by using mainly resonance Raman and X-ray spectroscopies as the main technique.

Our studies of the structure of PANI intercalated into MMT layers obtained by polymerization in aqueous suspension has modified-JGB-like units (*m*-JGB) in its backbone (see **Figure 4**) [15, 16, 24]. This result was very important in the literature because clearly shown that only using more conventional techniques, such as FTIR and EPR, is not possible to infer conclusively the exact nature of the PANI structure. In addition, our resonance Raman and X-ray absorption studies showed that intercalated PANI has a different chemical backbone than the conventional polymer (free PANI in its emeraldine salt state). More recently, we are interested to investigate the changes of the molecular structure of intercalated anilinium into montmorillonite clay (An+ -MMT) during heating treatment. **Figure 5** shows the resonance Raman spectra of An+ -MMT (see ref. [15, 16] for the description of synthesis of An+ -MMT) under heating at 100°C as a function of time. It is possible to see that the relative intensities of bands related to polaronic units of PANI at ca. 1180 and 1340 cm−1, and also the bands related to cross-linked phenazinic segments at 580, 1380, and 1645 cm−1 increase as the time under heating also increases. These changes can be associated to the polymerization of intercalated An+ without the use of external oxidant, like ammonium persulfate. After one day, there is no more changing.

### **Figure 4.**

*Schematic representation of intercalation of anilinium (an+ ) ion into MMT clay layers and their following polymerization in two different routes. XRD patterns and d*001 *values of powdered samples were obtained on a Rigaku diffractometer model Miniflex using Cu K*α *radiation (1.541 Å, 30 kV, 15 mA, step of 0.05<sup>o</sup> ). The possible molecular structures of intercalated PANIs are also displayed.*

**9**

**Figure 5.**

and PANI-MMT composites.

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials*

Hence, it must to emphasize that the RR spectrum of PANI-MMT prepared by heating treatment (spectrum at 24 h) is completely different to the PANI-MMT prepared by *in situ* polymerization in aqueous suspension (spectrum in red). The characteristics bands related to Janus green-like (JGB) units (1203, 1408, and 1632 cm−1) are not observed in the spectrum of PANI-MMT prepared by heating. Hence, the possibility to obtain a PANI only by heating is also very important, however the results clearly show that the polymer obtained in this route is also different from the PANI-MMT obtained from suspension route (see **Figure 4**). This new result clearly demonstrated the great potential of the resonance Raman to the elucidation of structures of intercalated polymers into clay nanocomposites. We also have recently studied the thermal effects over the structure of PANI-MMT nanocomposites. **Figure 6** shows the resonance Raman spectra of PANI-MMT nanocomposites obtained by suspension route and submitted to heating process in air atmosphere at indicated temperatures. The samples were irradiated with 632.8 nm (E0 = 1.96 eV) and 488.0 nm (E0 = 2.54 eV) laser lines. The first thing to be considered is that PANI-MMT nanocomposites showed signal up to 300°C (similar behavior was observed for *in situ* Raman measurements during heating [24]). The bands related to the *m*-JGB (see **Figure 4** and Raman spectra at 632.8 nm in **Figure 6**) groups are seen up to 200°C, at higher temperatures the bands at 1201, 1412 and 1630 cm−1 (related to the *m*-JGB segments) decrease, but at the same time, the bands at 574, 1401, and 1620 cm−1 assigned to Oxazine-like units (cross-linking segments, see **Figure 4**) increase. At 488.0 nm, a similar behavior is observed; however only the band at 1401 cm−1 associated to Oxazine-like units is clearly seen. This behavior can be rationalized considering that *m*-JGB units are degraded at higher temperatures and the cross-linked PANI-ES bands prevails, it shows that the intercalated polymer has higher thermal resistance than observed in free PANI-ES

*-MMT* 

*Resonance Raman spectra of PANI-MMT nanocomposite obtained by suspension route and the an<sup>+</sup>*

*irradiated with 632.8 nm (E . eV* <sup>0</sup> = 1 96 *) line of a He–Ne laser.*

*material under different times (indicated in the figure) of heating at 100°C in air inside an oven. All experiment was done at 100°C. the spectra were acquired in a Renishaw Raman system 3000 equipped with a CCD detector and an Olympus microscope. The laser beam was focused on sample by a 50x lens. Laser power was always kept below 0.7 mW at the sample in order to avoid laser-induced sample degradation. The experiments were performed under ambient conditions using a back-scattering geometry. The samples were* 

*DOI: http://dx.doi.org/10.5772/intechopen.95825*

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials DOI: http://dx.doi.org/10.5772/intechopen.95825*

### **Figure 5.**

*Resonance Raman spectra of PANI-MMT nanocomposite obtained by suspension route and the an<sup>+</sup> -MMT material under different times (indicated in the figure) of heating at 100°C in air inside an oven. All experiment was done at 100°C. the spectra were acquired in a Renishaw Raman system 3000 equipped with a CCD detector and an Olympus microscope. The laser beam was focused on sample by a 50x lens. Laser power was always kept below 0.7 mW at the sample in order to avoid laser-induced sample degradation. The experiments were performed under ambient conditions using a back-scattering geometry. The samples were irradiated with 632.8 nm (E . eV* <sup>0</sup> = 1 96 *) line of a He–Ne laser.*

Hence, it must to emphasize that the RR spectrum of PANI-MMT prepared by heating treatment (spectrum at 24 h) is completely different to the PANI-MMT prepared by *in situ* polymerization in aqueous suspension (spectrum in red). The characteristics bands related to Janus green-like (JGB) units (1203, 1408, and 1632 cm−1) are not observed in the spectrum of PANI-MMT prepared by heating. Hence, the possibility to obtain a PANI only by heating is also very important, however the results clearly show that the polymer obtained in this route is also different from the PANI-MMT obtained from suspension route (see **Figure 4**). This new result clearly demonstrated the great potential of the resonance Raman to the elucidation of structures of intercalated polymers into clay nanocomposites.

We also have recently studied the thermal effects over the structure of PANI-MMT nanocomposites. **Figure 6** shows the resonance Raman spectra of PANI-MMT nanocomposites obtained by suspension route and submitted to heating process in air atmosphere at indicated temperatures. The samples were irradiated with 632.8 nm (E0 = 1.96 eV) and 488.0 nm (E0 = 2.54 eV) laser lines. The first thing to be considered is that PANI-MMT nanocomposites showed signal up to 300°C (similar behavior was observed for *in situ* Raman measurements during heating [24]).

The bands related to the *m*-JGB (see **Figure 4** and Raman spectra at 632.8 nm in **Figure 6**) groups are seen up to 200°C, at higher temperatures the bands at 1201, 1412 and 1630 cm−1 (related to the *m*-JGB segments) decrease, but at the same time, the bands at 574, 1401, and 1620 cm−1 assigned to Oxazine-like units (cross-linking segments, see **Figure 4**) increase. At 488.0 nm, a similar behavior is observed; however only the band at 1401 cm−1 associated to Oxazine-like units is clearly seen. This behavior can be rationalized considering that *m*-JGB units are degraded at higher temperatures and the cross-linked PANI-ES bands prevails, it shows that the intercalated polymer has higher thermal resistance than observed in free PANI-ES and PANI-MMT composites.

### **Figure 6.**

*Resonance Raman spectra of PANI-MMT nanocomposite obtained by suspension route and submitted of heating at indicated temperature in air inside an oven. The spectra were acquired in a Renishaw Raman system 3000 equipped with a CCD detector and an Olympus microscope. The laser beam was focused on sample by a 50x lens. Laser power was always kept below 0.7 mW at the sample in order to avoid laser-induced sample degradation. The experiments were performed under ambient conditions using a back-scattering geometry. The samples were irradiated with 632.8 nm (E . eV* <sup>0</sup> = 1 96 *) line of a He–Ne laser and 488.0 nm (E . eV )* <sup>0</sup> = 2 54 *line of an Ar+ laser.*

### **Figure 7.**

*N K XANES spectra of powered samples of PANI-MMT nanocomposites. The black top continuous line represents experimental spectra. The Voigt bands used in the deconvolution of the experimental spectrum are shown below the experimental data (red dashed lines,* − *– –). The sum spectrum of the Voigt bands is also displayed (red pointed line, · · ·). The Si K XANES spectra of powered samples of MMT and PANI-MMT are also shown inside the figure. Silicon K-edge spectra were recorded using the total electron yield detection and the samples chamber at ca. 10−6 Pa. All energy values in the Si K-edge spectra were calibrated using the first resonant peak in the Si K XANES spectra for monocrystalline silicon.*

The X-ray absorption studies permit the study of polymer and clay at same time just by selection of appropriate photon energy to probe a specific atomic edge.

**11**

**Author details**

derived from clays.

morari@yahoo.com

Gustavo Morari do Nascimento

provided the original work is properly cited.

Federal University of ABC, CCNH, Santo André, Brazil

\*Address all correspondence to: gustavo.morari@ufabc.edu.br;

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials*

Our group have been studied a lot of nitrogen and silicon contend compounds in order to understand to the influence of the chemical structures and its environments over the atomic edges values (mainly Nitrogen, Carbon and Silicon). For instance, **Figure 7** shows the XANES spectra at N and Si K edges of the PANI-MMT nanocomposites. The N K edge gives many peaks related to the complex conjugated structure of the PANI. However, at Si K edge the spectra are simpler due to the regularity of silicon sites into clay layers and by the small influence of intercalated

The screening of the electronic and vibrational structure of polymer-clay nanocomposite through resonance Raman and X-ray absorption spectroscopies has been decisive in determination of their structure and in the study of the interactions between the clays and intercalated polymers in a myriad of synthetic conditions. In fact, by selecting the appropriate photon energies it is possible to study in particular the specific segment of the polymer or clay. The new Raman instruments and new synchrotron rings can give better spectroscopic data associated to a very higher spatial resolution. This open the possibility to study localized inhomogeneity, specific chemical modifications and many other aspects of these extraordinary materials

*DOI: http://dx.doi.org/10.5772/intechopen.95825*

polymer over the electronic properties of clays.

**3. Conclusion and future remarks**

*Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials DOI: http://dx.doi.org/10.5772/intechopen.95825*

Our group have been studied a lot of nitrogen and silicon contend compounds in order to understand to the influence of the chemical structures and its environments over the atomic edges values (mainly Nitrogen, Carbon and Silicon). For instance, **Figure 7** shows the XANES spectra at N and Si K edges of the PANI-MMT nanocomposites. The N K edge gives many peaks related to the complex conjugated structure of the PANI. However, at Si K edge the spectra are simpler due to the regularity of silicon sites into clay layers and by the small influence of intercalated polymer over the electronic properties of clays.

### **3. Conclusion and future remarks**

The screening of the electronic and vibrational structure of polymer-clay nanocomposite through resonance Raman and X-ray absorption spectroscopies has been decisive in determination of their structure and in the study of the interactions between the clays and intercalated polymers in a myriad of synthetic conditions. In fact, by selecting the appropriate photon energies it is possible to study in particular the specific segment of the polymer or clay. The new Raman instruments and new synchrotron rings can give better spectroscopic data associated to a very higher spatial resolution. This open the possibility to study localized inhomogeneity, specific chemical modifications and many other aspects of these extraordinary materials derived from clays.

### **Author details**

Gustavo Morari do Nascimento Federal University of ABC, CCNH, Santo André, Brazil

\*Address all correspondence to: gustavo.morari@ufabc.edu.br; morari@yahoo.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[20] Do Nascimento GM, Padilha ACM, Constantino VRL, Temperini MLA. Oxidation of anilinium ions intercalated in montmorillonite clay by electrochemical route. Colloids Surf. A: Physicochem. Eng. Aspects 2008;318:245.

[21] Do Nascimento GM, Temperini MLA. Structure of polyaniline formed in different inorganic porous materials: A spectroscopic study. Eur. Polym. J. 2008;44:3501.

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[25] Do Nascimento GM. Structure of Clays and Polymer–Clay Composites Studied by X-ray Absorption Spectroscopies. In: Do Nascimento GM, editor. (Org) Clays, Clay Minerals and Ceramic Materials Based on Clay Minerals 1st ed. London: InTech; 2016.

[26] Do Nascimento GM, Silva JEP, De Torresi SIC, Santos PS, Temperini MLA. Spectroscopic Characterization of the Inclusion Compound Formed by Polyaniline and β-Cyclodextrin. Mol. Cryst. Liq. Cryst., 2002;374:53.

[27] Do Nascimento GM. Spectroscopy of Polyaniline Nanofibers. In: Kumar A, editor. (Org.)Nanofibers. 1st ed. Austria/Croacia: InTech; 2010.

[28] Do Nascimento GM. Resonance Raman of Polyaniline Nanofibers In: Michaelson L, editor. (Org.) Advances in Conducting Polymers Research. 1st ed. New York: Nova Publishers; 2014.

[29] Do Nascimento GM. Raman dispersion in polyaniline nanofibers. Vibrational Spectroscopy. 2017;90:89

[30] Dresselhaus MS, Dai H. Carbon Nanotubes: Continued Innovations and Challenges MRS Bulletin 2004;29:237.

[31] Saito R, Fujita M, Dresselhaus G, Dresselhaus MS. Electronic structure of graphene tubules based on C60*Phys. Rev. B* 1992;46:1804.

[32] Dresselhaus MS, Dresselhaus G, Avouris Ph. *Carbon Nanotubes: Synthesis, Structure, Properties and Applications,* Inc: Springer-Verlag, Berlin, 2001.

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[34] Do Nascimento GM, Hou T, Kim YA, Muramatsu H, Hayashi T, Endo M, Akuzawa N, Dresselhaus MS. Double-Wall Carbon Nanotubes Doped with Different Br2 Doping Levels: A Resonance Raman Study Nano Lett. 2008;8:4168.

[35] Do Nascimento GM, Hou T, Kim YA, Muramatsu H, Hayashi T, Endo M, Akuzawa N, Dresselhaus MS. Comparison of the Resonance Raman Behavior of Double-Walled Carbon Nanotubes Doped with Bromine or Iodine Vapors. J Phys. Chem. C 2009;113:3934.

[36] Do Nascimento GM, De Oliveira RC, Pradie NA, Lins PRG, Worfel PR, Martinez GR, Di Mascio P, Dresselhaus MS, Corio P. Single-wall carbon nanotubes modified with organic dyes: Synthesis, characterization and potential cytotoxic effects J. Photochem. Photobiol. A Chem. 2010;211:99.

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**15**

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[52] Liepins R, Ku CC. Electrical Properties of Polymers, C. H. Verlag, Munich, 1987.

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**17**

**Chapter 2**

**Abstract**

engineering field.

**1. Introduction**

*Tanushree Choudhury*

Clay Hybrid Materials

The modern trend is to prepare hybrid material using nano clay. Formation of nano clay, an exfoliated clay, and proper dispersion in a polymer matrix remains a challenge. The green composite so formed by clay polymer mixing has many improved properties such as high Tg (glass transition temperature), high flame resistance, high tensile strength, and improved barrier properties, which may find application in textile industry, automobile industry, environmental and polymer

Hybrid Materials, in general, have enhanced properties to their components alone. Some of the properties of these hybrid materials, which have been studied in depth, are moduli, thermal expansion coefficients, gas permeability, ionic conductivity, etc. These hybrid materials are classified based on their interaction between host and guest phases. Depending on the type of matrix and guest phase, hybrid materials have been classified into three groups: (i) "OI" organic-inorganic or molecular hybrids, "IO" inorganic-organic intercalation compounds, nanocomposite materials, and solid-state hybrids exhibited by clay-calixarene derivatives [1]. One of such hybrid materials is clay-based hybrid material. Clay minerals are aluminosilicates. Though different types of clay have been used, for making hybrid materials, one of the most commonly used clay is montmorillonite. It belongs to 2:1 type of clay, two silicate layers and one octahedral brucite type of layer containing a mostly aluminum-oxygen hydroxyl group. Isomorphous substitution of trivalent Al3+ ion by divalent/monovalent or tetrahedral Si with trivalent Al3+ ion leads to charge imbalance in the crystal. This imbalance is compensated by the presence of counter ions present at the surface of the sheet layer. The edge of each platelet has a

Clay particles are small in size <2 μm, have a large surface area-to-mass ratio. The counter ions (at the exchangeable sites on clay) along with water molecules also

Exchangeable cations adsorbed on the surface layer can be replaced by other materials. Inherently clay surfaces are hydrophilic attracting polar groups. However, they can be made oleophilic by exchanging the cations with organic ions like cetyl trimethyl ammonium bromide ions or cetyl trimethyl ammonium pyridinium ions etc., producing organoclay composites or polymer clay nanocomposites (PCNs). These composites are extremely investigated in material science and find widespread applications as adsorbents for heavy metal ions [2–4], ceramics and thin films [5], building materials [6], photocatalysts for wastewater treatment [7, 8],

**Keywords:** nano clay, dispersion, CTAB, organic modifier, properties

hydroxide group allowing it to form water gels.

serve a bridge between the two layers keeping them inbound.

## **Chapter 2** Clay Hybrid Materials

*Tanushree Choudhury*

### **Abstract**

The modern trend is to prepare hybrid material using nano clay. Formation of nano clay, an exfoliated clay, and proper dispersion in a polymer matrix remains a challenge. The green composite so formed by clay polymer mixing has many improved properties such as high Tg (glass transition temperature), high flame resistance, high tensile strength, and improved barrier properties, which may find application in textile industry, automobile industry, environmental and polymer engineering field.

**Keywords:** nano clay, dispersion, CTAB, organic modifier, properties

### **1. Introduction**

Hybrid Materials, in general, have enhanced properties to their components alone. Some of the properties of these hybrid materials, which have been studied in depth, are moduli, thermal expansion coefficients, gas permeability, ionic conductivity, etc. These hybrid materials are classified based on their interaction between host and guest phases. Depending on the type of matrix and guest phase, hybrid materials have been classified into three groups: (i) "OI" organic-inorganic or molecular hybrids, "IO" inorganic-organic intercalation compounds, nanocomposite materials, and solid-state hybrids exhibited by clay-calixarene derivatives [1].

One of such hybrid materials is clay-based hybrid material. Clay minerals are aluminosilicates. Though different types of clay have been used, for making hybrid materials, one of the most commonly used clay is montmorillonite. It belongs to 2:1 type of clay, two silicate layers and one octahedral brucite type of layer containing a mostly aluminum-oxygen hydroxyl group. Isomorphous substitution of trivalent Al3+ ion by divalent/monovalent or tetrahedral Si with trivalent Al3+ ion leads to charge imbalance in the crystal. This imbalance is compensated by the presence of counter ions present at the surface of the sheet layer. The edge of each platelet has a hydroxide group allowing it to form water gels.

Clay particles are small in size <2 μm, have a large surface area-to-mass ratio. The counter ions (at the exchangeable sites on clay) along with water molecules also serve a bridge between the two layers keeping them inbound.

Exchangeable cations adsorbed on the surface layer can be replaced by other materials. Inherently clay surfaces are hydrophilic attracting polar groups. However, they can be made oleophilic by exchanging the cations with organic ions like cetyl trimethyl ammonium bromide ions or cetyl trimethyl ammonium pyridinium ions etc., producing organoclay composites or polymer clay nanocomposites (PCNs). These composites are extremely investigated in material science and find widespread applications as adsorbents for heavy metal ions [2–4], ceramics and thin films [5], building materials [6], photocatalysts for wastewater treatment [7, 8],

### *Clay Science and Technology*

drug delivery vehicle [9], bio-inspired materials [10], optoelectronic devices [11], ferrofluids [12], and hydrogel clay hybrids for pesticide and nutrient retention [13].

This review focuses on the properties of the different types of clay hybrid materials that can be prepared by intercalation chemistry, in situ polymerization and sol-gel techniques. It would also provide an insight into the application of these hybrids for a sustainable environment.

### **2. Clay-based hybrid materials**

### **2.1 How clay can be used in a hybrid material**

### *2.1.1 Structure of clay*

Clay minerals belong to phyllosilicates. The principal building elements of the clay minerals are two-dimensional arrays of Si-O- tetrahedral and 2-D arrays of Al or Mg-O-OH octahedral as shown in **Figure 1**. In most clay minerals, such sheets of tetrahedral and octahedral are superimposed in different fashions [14].


In 2:1 layer minerals, one alumina or magnesia sheet shares oxygen atoms with two silica sheets, one on each side. These layers in clay minerals are stacked parallel to each other.

### **2.2 Origin of surface charge and modification of clay surface**

In the tetrahedral sheet, tetravalent Si is sometimes partly replaced by trivalent Al. In the octahedral sheet, there may be replacement of trivalent Al by divalent Mg without complete filling of the third vacant octahedral position. Al atoms may also be replaced by Fe, Cr, Zn, Li, and other atoms. The small size of these atoms permits them to take the place of small Si and Al atoms; therefore, the replacement is often referred to as isomorphous substitution. When an atom of lower positive charge replaces one of higher valence, a deficit of positive charge takes place or in other words, excess of negative charge. This excess of negative charge is compensated by the adsorption on the layer surfaces of cation, which are too large to be accommodated in the interior of the crystal. In the presence of water, the compensating cations on the layer surfaces may be easily exchanged by other cations when available in solution, hence they are called exchangeable cations. Thus clay minerals bear the potential of forming hybrid materials.

**19**

in **Figure 2**.

*Clay Hybrid Materials*

**Figure 1.**

*Structure of clay mineral.*

*DOI: http://dx.doi.org/10.5772/intechopen.92529*

Natural clay is hydrophilic. The surface of the clay needs to be modified so that it can interact with hydrophobic polymers. The modification of clay surface is generally done by the cation exchange process. The ability of clays to exchange cations between each of their layers and retain them is a unique characteristic. The intercalated cations can be exchanged by other cations by treatment of other cations in solution. This cation exchange capacity can be defined as the maximum amount of cations that a given amount of clay can take up and this is constant. The ability to cation exchange in the interlayer space determines the adsorption ability of montmorillonite [15]. The most exchangeable cations that can be adsorbed on the clay surface

amines, amino acids, cationic surfactants, and non-ionic surfactants. The surface of the clay can also be rendered organophilic by the reaction of hybrid monolayers of clay mineral and amphiphilic alkyl amino cation using Langmuir-Blodget method [16]. When a solution of an amphiphilic alkyl ammonium cation is spread onto clay suspension, negatively charged clay platelets in the suspension are adsorbed onto a floating monolayer of the alkylammonium cation at an air-clay suspension interface. The hybrid monolayers of clay platelets and alkylammonium cations formed at the interface can be transferred onto a solid surface to fabricate a hybrid multilayer.

**Intercalation compounds:** These compounds result from the intracrystalline insertion of organic compounds inside the layers of certain lamellar solids as shown

, Ca2+, Mg2+, K+

),

by the cation-exchange process are inorganic ions (mostly Na+

The common types of clay hybrid materials are:

**2.3 Types of clay hybrid materials**

1.Intercalation compounds

3.Sol-gel hybrid materials

2.Exfoliated/delaminated compounds

*Clay Science and Technology*

hybrids for a sustainable environment.

**2. Clay-based hybrid materials**

*2.1.1 Structure of clay*

**2.1 How clay can be used in a hybrid material**

drug delivery vehicle [9], bio-inspired materials [10], optoelectronic devices [11], ferrofluids [12], and hydrogel clay hybrids for pesticide and nutrient retention [13]. This review focuses on the properties of the different types of clay hybrid materials that can be prepared by intercalation chemistry, in situ polymerization and sol-gel techniques. It would also provide an insight into the application of these

Clay minerals belong to phyllosilicates. The principal building elements of the clay minerals are two-dimensional arrays of Si-O- tetrahedral and 2-D arrays of Al or Mg-O-OH octahedral as shown in **Figure 1**. In most clay minerals, such sheets of

a.**Structure of tetrahedral sheet:** In the Si-O sheets, the Si atoms are coordinated with four oxygen atoms. The O atoms are located on the four corners of a regular tetrahedron with the Si atom in the center. In the sheet, three of the four oxygen atoms of each tetrahedron are shared by three neighboring tetrahedral. The fourth oxygen atom of each tetrahedron is pointed downward.

b.**Structure of octahedral sheet:** In the Al, Mg-O-OH sheets, the Al or Mg

atoms are coordinated with six oxygen atoms or –OH groups, which are located around the Al or Mg atom, with their centers on the corners of a regular

octahedron resulting in hexagonal close packing. This sheet is called alumina or magnesia sheet. The fourth oxygen atom protruding from the tetrahedral sheet is shared by the octahedral sheet. This sharing of atoms may occur between one

In 2:1 layer minerals, one alumina or magnesia sheet shares oxygen atoms with two silica sheets, one on each side. These layers in clay minerals are stacked parallel

In the tetrahedral sheet, tetravalent Si is sometimes partly replaced by trivalent Al. In the octahedral sheet, there may be replacement of trivalent Al by divalent Mg without complete filling of the third vacant octahedral position. Al atoms may also be replaced by Fe, Cr, Zn, Li, and other atoms. The small size of these atoms permits them to take the place of small Si and Al atoms; therefore, the replacement is often referred to as isomorphous substitution. When an atom of lower positive charge replaces one of higher valence, a deficit of positive charge takes place or in other words, excess of negative charge. This excess of negative charge is compensated by the adsorption on the layer surfaces of cation, which are too large to be accommodated in the interior of the crystal. In the presence of water, the compensating cations on the layer surfaces may be easily exchanged by other cations when available in solution, hence they are called exchangeable cations. Thus clay minerals bear

tetrahedral and octahedral are superimposed in different fashions [14].

This Si-O sheet is called a tetrahedral sheet or silica sheet.

silica and one alumina sheet as 1:1 layer minerals.

**2.2 Origin of surface charge and modification of clay surface**

the potential of forming hybrid materials.

**18**

to each other.

Natural clay is hydrophilic. The surface of the clay needs to be modified so that it can interact with hydrophobic polymers. The modification of clay surface is generally done by the cation exchange process. The ability of clays to exchange cations between each of their layers and retain them is a unique characteristic. The intercalated cations can be exchanged by other cations by treatment of other cations in solution. This cation exchange capacity can be defined as the maximum amount of cations that a given amount of clay can take up and this is constant. The ability to cation exchange in the interlayer space determines the adsorption ability of montmorillonite [15]. The most exchangeable cations that can be adsorbed on the clay surface by the cation-exchange process are inorganic ions (mostly Na+ , Ca2+, Mg2+, K+ ), amines, amino acids, cationic surfactants, and non-ionic surfactants. The surface of the clay can also be rendered organophilic by the reaction of hybrid monolayers of clay mineral and amphiphilic alkyl amino cation using Langmuir-Blodget method [16]. When a solution of an amphiphilic alkyl ammonium cation is spread onto clay suspension, negatively charged clay platelets in the suspension are adsorbed onto a floating monolayer of the alkylammonium cation at an air-clay suspension interface. The hybrid monolayers of clay platelets and alkylammonium cations formed at the interface can be transferred onto a solid surface to fabricate a hybrid multilayer.

### **2.3 Types of clay hybrid materials**

The common types of clay hybrid materials are:


**Intercalation compounds:** These compounds result from the intracrystalline insertion of organic compounds inside the layers of certain lamellar solids as shown in **Figure 2**.


**Exfoliated or delaminated compounds:** These compounds are formed when the layers of clay are delaminated and the resulting platelets are homogeneously dispersed throughout the polymer matrix as shown in **Figure 3**. The resulting materials

**21**

*Clay Hybrid Materials*

mers is discussed below.

**Figure 3.** *Exfoliated clay.*

*DOI: http://dx.doi.org/10.5772/intechopen.92529*

are considered as nanocomposites as the interaction takes place at the atomic level

Clay mineral is a potential candidate for the filler of these hybrid materials since it is composed of layered silicates, 1 nm thick, which can undergo intercalation with organic molecules [23]. The mechanism of interaction of clay with different poly-

i.Vinyl polymers: These include vinyl addition polymers derived from monomers like methyl methacrylate [24–30], acrylic acid [31], vinyl ester [32], vinyl polymer [33, 34], styrene [35–38], allyl ester resin [39], and acrylates [40].

Studying the mechanism of interaction of ethylene-vinyl acetate with clay, it has been found that as VA (vinyl acetate) content increases, copolymer presents increasing polarity but lower crystallinity with different mechanical behavior. Increasing polarity with increasing VA content is useful in imparting a high degree of polymer-clay surface interaction. Structure and mobility properties of EVA polymer are influenced by VA content and this chain mobility in and around clay galleries tend to modify the level of interaction in clay hybrid materials [41]. Polymer chains of PVA get adsorbed on individual inorganic lamellae in stages after the exfoliation of the clay mineral leading to the formation of intercalated nanocomposites [42]. PVA forms a composite structure with sodium montmorillonite and studies reveal the existence of both exfoliated and intercalated MMT layers for low and moderate silicate loadings. Exfoliation of layers has been attributed to water casting method used since the water suspended layers become kinetically trapped by the polymer and cannot reaggregate [43]. Syndiotactic PS (thermoplastic polymer) differs from other PS (such as a-PS) in that phenyl rings regularly alternate from side to side concerning polymer chain backbone. Two important factors responsible for homogenous dispersion of clay layers in s-PS hybrids are: (a) surfactant should be intercalated between silicate layers of clay by ionic bonding and (b) the hydrophobic tail of the surfactant molecule should be partially compat-

Organophilic modification of clay and amine-terminated PS employing anionic polymerization yielded completely exfoliated hybrids with aspect ratio exceeding 600 when such organoclays were melt compounded with PS. In contrast to this, small molecular weight modifiers only promoted intercalation and failed to exfoliate silicate particles during melt compounding. ABS (thermoplastic polymer) forms

between inorganic hosts and organic guest molecules.

ible or interacted with s-PS molecules [44].

**Figure 2.** *Intercalated clay.*

**Figure 3.** *Exfoliated clay.*

*Clay Science and Technology*

intercalation with organic anions [18].

guest molecule [22].

i.Intercalation of ionic species: Clay minerals exhibit isomorphous substitution as a result of which Si is replaced by Al in a tetrahedral layer or Al by Mg in octahedral layer leading to charge deficiency, which in turn is compensated by exchangeable cations. Exchangeable metal ions located in the interlamellar space of MMT may be replaced by different organic cations such as alkylammonium ions in solution. Alkylammonium cations thus incorporated in organosilicates lower the surface energy of inorganic hosts and improve the wetting characteristic with polymer [17]. It provides a functional group that can react with polymer or initiate polymerization of monomers to improve interfacial strength between inorganic host and polymer. Layered double hydroxides (LDH), for example, Mg6Al2(OH)16CO3. 4H2O, have a positive charge on the Mg (OH)2 layers. They provide an opportunity for

ii.Intercalation of neutral species: Formation of organic-inorganic compounds by intercalation of neutral molecules in 2D solids, generally phyllosilicates of clay minerals family and it is also observed for other inorganic layered materials, for example, 2D transition metal halides, oxyhalides, dichalcogenides, graphite, and graphite oxide, layered phosphates, phosphorous trichalcogenides. Different mechanisms are proposed that come into play during host-guest interactions in these intercalated materials. Van der Waals forces mainly occur when long-chain alkylammonium ions are inserted in the clay layers. When interlayer cations preserve the hydration shell, an association of molecules takes place with water molecule acting as H bond bridges, which on heating, eliminates water and produces direct coordination between guest species and involved transition metal [19]. Macrocyclic compounds such as crown ether and cryptands penetrate the interlayer space of phyllosilicates and other layered solids giving stable intracrystalline complexes [20]. The interlayer environment of certain layered solids exhibits acid character, which is typical of clay minerals group. Interaction with basic species produces a proton transfer between the inorganic host and organic guest molecule. The organic molecules being protonated gives rise to organic cations balancing the electrical charge of the silicate [21]. Many redox reactions occur during intercalation of organic and organometallic species into various 2D solids. Clays containing interlayer cations like Cu (II) can interact with aromatic compounds such as benzene giving intercalation compounds characterized by the existence of σ or π bonds between the host solid and

**Exfoliated or delaminated compounds:** These compounds are formed when the layers of clay are delaminated and the resulting platelets are homogeneously dispersed throughout the polymer matrix as shown in **Figure 3**. The resulting materials

**20**

**Figure 2.** *Intercalated clay.* are considered as nanocomposites as the interaction takes place at the atomic level between inorganic hosts and organic guest molecules.

Clay mineral is a potential candidate for the filler of these hybrid materials since it is composed of layered silicates, 1 nm thick, which can undergo intercalation with organic molecules [23]. The mechanism of interaction of clay with different polymers is discussed below.

i.Vinyl polymers: These include vinyl addition polymers derived from monomers like methyl methacrylate [24–30], acrylic acid [31], vinyl ester [32], vinyl polymer [33, 34], styrene [35–38], allyl ester resin [39], and acrylates [40].

Studying the mechanism of interaction of ethylene-vinyl acetate with clay, it has been found that as VA (vinyl acetate) content increases, copolymer presents increasing polarity but lower crystallinity with different mechanical behavior. Increasing polarity with increasing VA content is useful in imparting a high degree of polymer-clay surface interaction. Structure and mobility properties of EVA polymer are influenced by VA content and this chain mobility in and around clay galleries tend to modify the level of interaction in clay hybrid materials [41]. Polymer chains of PVA get adsorbed on individual inorganic lamellae in stages after the exfoliation of the clay mineral leading to the formation of intercalated nanocomposites [42]. PVA forms a composite structure with sodium montmorillonite and studies reveal the existence of both exfoliated and intercalated MMT layers for low and moderate silicate loadings. Exfoliation of layers has been attributed to water casting method used since the water suspended layers become kinetically trapped by the polymer and cannot reaggregate [43]. Syndiotactic PS (thermoplastic polymer) differs from other PS (such as a-PS) in that phenyl rings regularly alternate from side to side concerning polymer chain backbone. Two important factors responsible for homogenous dispersion of clay layers in s-PS hybrids are: (a) surfactant should be intercalated between silicate layers of clay by ionic bonding and (b) the hydrophobic tail of the surfactant molecule should be partially compatible or interacted with s-PS molecules [44].

Organophilic modification of clay and amine-terminated PS employing anionic polymerization yielded completely exfoliated hybrids with aspect ratio exceeding 600 when such organoclays were melt compounded with PS. In contrast to this, small molecular weight modifiers only promoted intercalation and failed to exfoliate silicate particles during melt compounding. ABS (thermoplastic polymer) forms an intercalated-exfoliated composite with clay. HENA (hydroxyethyl isonicotinamide) is used as an anchor monomer for homogeneous dispersion of clay minerals in PET (polyethene terephthalate) matrix [45].

Acrylonitrile co-monomer incorporated into poly (styrene-co-acrylonitrile) copolymer accelerates intercalation of copolymers into the galleries of silicate layers modified with an organic intercalant. The faster intercalation of a matrix polymer leads to the better dispersion of silicate layers in the matrix polymer [46]. In the hybrids of SAN, clay particles or nanoscale building blocks are distributed uniformly and their sizes are strongly dependent on co-monomer content. Acrylonitrile co-monomer incorporated into SAN facilitates the intercalation of copolymers into the galleries of silicate layers modified with an intercalant. H-bonding interaction between the nitrile groups of SAN and –OH groups on silicate layer makes a negative contribution to exchange energy of mixing so that the intercalation of copolymers into the galleries of the silicate layer is accelerated. It is also expected that the enhanced polarity of SAN due to incorporated acrylonitrile co-monomer can destroy H-bondings of intercalant in the galleries. This might also increase the rate of intercalation of SAN into the galleries of silicate layers modified with intercalants. Synthesis of hybrid materials using natural clay and modified PVC resulted in the removal of heavy metals (Fe, Cu, Pb, Zn, Cd, Co, and Mn) from aqueous solution and also exhibited good adsorption capacity for Fe (III) [47].

ii.Condensation step polymers: Several important polycondensates have been used in nanocomposites preparation with layered silicates. They are polyamides [48], polyimides [49], polyurethane urea [50], polyurethane [51], poly (butylene terephthalate) [52], poly (ethylene terephthalate co-ethylene naphthalate) [53], epoxy [54, 55], amino, sulfonic acid, and silyl functionalized groups [56–59], and surface-modified groups [60].

Polyamides and polyimides are polymers containing polar functional groups and form homogenous and exfoliated dispersion of silicate layers as silicate layers of clay have polar functional groups and are compatible only with polymers containing polar functional groups. Polyamide-6 (PA6), Polyamide 66 (PA-66), and Nylon form majority of commercial polyamides. PA-66 contains a mixture of chains (only amines, acid groups, or a mixture of two). Differences in end group configuration can lead to significant differences in morphology and properties of blends with functionalized polymers. A lower degree of exfoliation in PA-66 nanocomposites, the affinity of PA-66 for organoclay is less than PA-6 nanocomposites forming the basic aspect of difference in the chemical structure of two polyamides [61]. Nylon-6-clay hybrids (NCHs) have been prepared by using 10A0 silicate layers of clay minerals, which are dispersed homogeneously in the polymer matrices resulting in a drastic change in properties (high strength, high modulus, high heat and distortion temperature) and this has been achieved with only a few % of clay [62]. The compatibility of forming hybrids with clay and polymers containing amide and imide groups increases as both contain polar functional groups. PBI (polybenzimidazole) is a thermally stable thermoplastic polymer, contains 1,3-dinitrogen heterocycle. When PBI is added to clay suspensions in a polar environment, the mineral layers will first adsorb the bulky macromolecule and the intercalation proceeds to completion via exchanged sites of the organically modified clay [63]. Polyurethane (PU) elastomers are segmented polymers with soft segments derived from polyols and hard segments from isocyanates and chain extenders. Linear PU is obtained by poly condensate technique using a mixture of diols and diisocyanate. MMT nanolayers are dispersed in PU matrix replacing hydrophilic organic exchange cations of native mineral with more organophilic diethanolamine/triethanolamine. Presence

**23**

epoxy resin.

ening of interaction between layers.

*Clay Hybrid Materials*

with diisocyanate [64].

*DOI: http://dx.doi.org/10.5772/intechopen.92529*

of these groups in galleries of MMT renders them organophilic and promotes the absorption of diol into the interlayer of MMT and improves the particle-matrix interactions since di and triethanolamine contain functional groups, which react

Pure PU exhibits an amorphous halo at 20° in 2θ. The gallery spacing of the layered clay is 1.1 nm. The gallery spacing of the layered clay in the composites increases to 1.6 nm for the PU/layered nanocomposites. This indicates that PU chains were intercalated between the layers of clay [65]. A multilayered structure consisting of alternate PU chains stacked with the layers of the silicate layers in the microstructure of PU/OMT nanocomposites has been confirmed in literature [66]. With increasing and urgent market demand to produce higher performance electronic devices with a smaller size, lighter weight, and better quality, developing PI films with low coefficient of thermal expansion (CTE) has increasingly become one of the most important issues. The best way to lower the CTE of PI is to introduce low CTE inorganic materials such as clay into PI matrix, yielding PI/clay hybrid composites [67]. Polar aprotic solvents are used for the synthesis of these hybrids, but due to solvent-solute interaction, are not easily removed from the PAA film at temperatures used during thermal curing for PI. The residual solvent causes the PAA (polyamic acid)/clay films to be plasticized during thermal imidization and thus leads to PI/Clay hybrid films with relatively higher values in CTE, but lower than pure film. To eliminate such negative effects of the aprotic solvents on CTE, PAA solutions not containing them should be prepared. A novel PI/clay hybrid film prepared from PAA salt of triethylamine and organoclay in a mixed solvent of THF/ MeOH is described in the literature. It is expected that the hybrid will have a much

lower CTE than those obtained from PAA in an aprotic solvent.

Full separation of clay layers in the polymer matrix is also achieved by using epoxy resin, which has high polarity and curing property [68]. The presence of polar –OH groups in clay layers impede nonpolar species from entering the galleries and exfoliating the clay layers. The mechanism of clay exfoliation in epoxy clay systems have been studied and reported in the literature. According to it, the acidity of alkylammonium ions catalyze homopolymerization of diglycidyl ether of bisphenol A (DGEBA) molecules inside the clay galleries. CEC of clays determines the number of alkylammonium ions present between clay layers and therefore controls the space available for the diffusion of DGEBA molecules during mixing of organoclay with

iii.Polyolefins: These include polypropylene [69–74], polyethylene [75–77],

These polymers do not contain any polar groups and homogenous dispersion in the silicate matrix is difficult. Homogenous dispersion of silicate layers in PP is not realized even by using an MMT intercalated with di-stearyl ammonium ion (DSDM-MT) in which polar surfaces of clay are covered with nonpolar long alkyl groups. A novel method of preparing PP-clay hybrid has been developed. PP is mixed with DSDM-MT and polyolefin oligomer with polar telechelic –OH groups (PO-OH) as a compatibilizer. In this process, PO-OH oligomer intercalates between the layers of clay through the strong H-bonding between –OH groups of PO-OH and oxygen groups of silicates. Interlayer spacing increases thus resulting in weak-

Another method of preparing PP/clay nanocomposites is by improving the compatibility of PP with organoclay by functionalizing the backbones of PP with polar monomers such as epoxy and maleic anhydride (MA) [79]. Compatibilizers promote compatibility of clay and polymer for good nano dispersion. Polyolefin-graft

ethylene propylene diene methylene linkage rubber [78].

*Clay Science and Technology*

in PET (polyethene terephthalate) matrix [45].

an intercalated-exfoliated composite with clay. HENA (hydroxyethyl isonicotinamide) is used as an anchor monomer for homogeneous dispersion of clay minerals

Acrylonitrile co-monomer incorporated into poly (styrene-co-acrylonitrile) copolymer accelerates intercalation of copolymers into the galleries of silicate layers modified with an organic intercalant. The faster intercalation of a matrix polymer leads to the better dispersion of silicate layers in the matrix polymer [46]. In the hybrids of SAN, clay particles or nanoscale building blocks are distributed uniformly and their sizes are strongly dependent on co-monomer content. Acrylonitrile co-monomer incorporated into SAN facilitates the intercalation of copolymers into the galleries of silicate layers modified with an intercalant. H-bonding interaction between the nitrile groups of SAN and –OH groups on silicate layer makes a negative contribution to exchange energy of mixing so that the intercalation of copolymers into the galleries of the silicate layer is accelerated. It is also expected that the enhanced polarity of SAN due to incorporated acrylonitrile co-monomer can destroy H-bondings of intercalant in the galleries. This might also increase the rate of intercalation of SAN into the galleries of silicate layers modified with intercalants. Synthesis of hybrid materials using natural clay and modified PVC resulted in the removal of heavy metals (Fe, Cu, Pb, Zn, Cd, Co, and Mn) from aqueous solution and also exhibited good adsorption capacity for Fe (III) [47].

ii.Condensation step polymers: Several important polycondensates have been used in nanocomposites preparation with layered silicates. They are polyamides [48], polyimides [49], polyurethane urea [50], polyurethane [51], poly (butylene terephthalate) [52], poly (ethylene terephthalate co-ethylene naphthalate) [53], epoxy [54, 55], amino, sulfonic acid, and silyl functional-

Polyamides and polyimides are polymers containing polar functional groups and form homogenous and exfoliated dispersion of silicate layers as silicate layers of clay have polar functional groups and are compatible only with polymers containing polar functional groups. Polyamide-6 (PA6), Polyamide 66 (PA-66), and Nylon form majority of commercial polyamides. PA-66 contains a mixture of chains (only amines, acid groups, or a mixture of two). Differences in end group configuration can lead to significant differences in morphology and properties of blends with functionalized polymers. A lower degree of exfoliation in PA-66 nanocomposites, the affinity of PA-66 for organoclay is less than PA-6 nanocomposites forming the basic aspect of difference in the chemical structure of two polyamides [61]. Nylon-

minerals, which are dispersed homogeneously in the polymer matrices resulting in a drastic change in properties (high strength, high modulus, high heat and distortion temperature) and this has been achieved with only a few % of clay [62]. The compatibility of forming hybrids with clay and polymers containing amide and imide groups increases as both contain polar functional groups. PBI (polybenzimidazole) is a thermally stable thermoplastic polymer, contains 1,3-dinitrogen heterocycle. When PBI is added to clay suspensions in a polar environment, the mineral layers will first adsorb the bulky macromolecule and the intercalation proceeds to completion via exchanged sites of the organically modified clay [63]. Polyurethane (PU) elastomers are segmented polymers with soft segments derived from polyols and hard segments from isocyanates and chain extenders. Linear PU is obtained by poly condensate technique using a mixture of diols and diisocyanate. MMT nanolayers are dispersed in PU matrix replacing hydrophilic organic exchange cations of native mineral with more organophilic diethanolamine/triethanolamine. Presence

silicate layers of clay

ized groups [56–59], and surface-modified groups [60].

6-clay hybrids (NCHs) have been prepared by using 10A0

**22**

of these groups in galleries of MMT renders them organophilic and promotes the absorption of diol into the interlayer of MMT and improves the particle-matrix interactions since di and triethanolamine contain functional groups, which react with diisocyanate [64].

Pure PU exhibits an amorphous halo at 20° in 2θ. The gallery spacing of the layered clay is 1.1 nm. The gallery spacing of the layered clay in the composites increases to 1.6 nm for the PU/layered nanocomposites. This indicates that PU chains were intercalated between the layers of clay [65]. A multilayered structure consisting of alternate PU chains stacked with the layers of the silicate layers in the microstructure of PU/OMT nanocomposites has been confirmed in literature [66].

With increasing and urgent market demand to produce higher performance electronic devices with a smaller size, lighter weight, and better quality, developing PI films with low coefficient of thermal expansion (CTE) has increasingly become one of the most important issues. The best way to lower the CTE of PI is to introduce low CTE inorganic materials such as clay into PI matrix, yielding PI/clay hybrid composites [67]. Polar aprotic solvents are used for the synthesis of these hybrids, but due to solvent-solute interaction, are not easily removed from the PAA film at temperatures used during thermal curing for PI. The residual solvent causes the PAA (polyamic acid)/clay films to be plasticized during thermal imidization and thus leads to PI/Clay hybrid films with relatively higher values in CTE, but lower than pure film. To eliminate such negative effects of the aprotic solvents on CTE, PAA solutions not containing them should be prepared. A novel PI/clay hybrid film prepared from PAA salt of triethylamine and organoclay in a mixed solvent of THF/ MeOH is described in the literature. It is expected that the hybrid will have a much lower CTE than those obtained from PAA in an aprotic solvent.

Full separation of clay layers in the polymer matrix is also achieved by using epoxy resin, which has high polarity and curing property [68]. The presence of polar –OH groups in clay layers impede nonpolar species from entering the galleries and exfoliating the clay layers. The mechanism of clay exfoliation in epoxy clay systems have been studied and reported in the literature. According to it, the acidity of alkylammonium ions catalyze homopolymerization of diglycidyl ether of bisphenol A (DGEBA) molecules inside the clay galleries. CEC of clays determines the number of alkylammonium ions present between clay layers and therefore controls the space available for the diffusion of DGEBA molecules during mixing of organoclay with epoxy resin.

iii.Polyolefins: These include polypropylene [69–74], polyethylene [75–77], ethylene propylene diene methylene linkage rubber [78].

These polymers do not contain any polar groups and homogenous dispersion in the silicate matrix is difficult. Homogenous dispersion of silicate layers in PP is not realized even by using an MMT intercalated with di-stearyl ammonium ion (DSDM-MT) in which polar surfaces of clay are covered with nonpolar long alkyl groups. A novel method of preparing PP-clay hybrid has been developed. PP is mixed with DSDM-MT and polyolefin oligomer with polar telechelic –OH groups (PO-OH) as a compatibilizer. In this process, PO-OH oligomer intercalates between the layers of clay through the strong H-bonding between –OH groups of PO-OH and oxygen groups of silicates. Interlayer spacing increases thus resulting in weakening of interaction between layers.

Another method of preparing PP/clay nanocomposites is by improving the compatibility of PP with organoclay by functionalizing the backbones of PP with polar monomers such as epoxy and maleic anhydride (MA) [79]. Compatibilizers promote compatibility of clay and polymer for good nano dispersion. Polyolefin-graft

MA as compatibilizer is used to enhance the possibility of intercalation of polymer between clay layers. The presence of MA increases the possibility of nanocomposite formation for PS, but this does not appear to help PP. PP/clay nanocomposites modified with the optimum level of compatibilizer yielded the greatest improvement of composite properties [80].

PE (polyethene) is another widely used polyolefin polymers. Alkylammonium ion facilitates interaction with polymer because it renders hydrophilic clay surface organophilic. Organically modified clay is not well dispersed in nonpolar PE as the nonpolar groups are too hydrophobic. Exfoliation and interaction behaviors depended on the hydrophilicity of PE grafted with MA and chain length of the organic modifier in the clay. When the number of methylene groups in alkyl amine (organic modifier) was larger than 16, exfoliated nanocomposites were obtained and the MA grafting levels was higher than about 0.1 wt% for the exfoliated nanocomposite with modified clay [81].

Rubber is another such polymer. Carbon blacks are excellent reinforcers due to their strong interaction with rubbers, but they often decrease the processability of rubber compounds because of high viscosity at high volume loading. MMT exchanged with a liquid rubber (LR) is termed as LR-MMT for utilization of its favorable shape. Co-vulcanization of nitrile rubber was done with LR-MMT for the formation of the molecular composite. It has been studied that there exist strong rubber-filler interactions as (comparable to those in carbon black filled system) in LR MMT, in which negatively charged silicate layers are bonded to LR molecules with positively charged terminal sites forming "bound rubber."

Polymers grafted on silicate surfaces also helps in delamination of its layers. It has been reported in the literature that PDMS (polydimethylsiloxane) grafted onto MMT layer surface via condensation of hydroxyl groups of PDMS and those hydroxyl groups on MMT layers prevents the nanolayers of MMT from reaggregating.

Intercalation of EPDM chains into OMMT galleries provided a strong interaction between EPDM and OMMT sheets in exfoliated composites.

It has been observed that the photoluminescence quantum efficiency of conjugated polymer PE improves manifold in the presence of the inorganic phase like montmorillonite clay [82]. Incorporation of montmorillonite clays into conjugate polymers like PAni gives rise to hybrid/inorganic composites with special properties for application in organic light-emitting diodes (OLEDs), organic field-effect (OFETs), organic solar cells (OSCs), and electrochromic devices (ECDs) [83].


Metal incorporated clay composites such as phosphorous clay composites show improved fire performance [90].

Starch modified by grafting with vinyl monomers (e.g., methyl acrylate) onto the starch backbone yielded thermoplastic materials. Kaolin, a natural mineral, hydrated aluminosilicate, with high surface and presence of polar groups showed very good compatibility with thermoplasticized starch.

Aliphatic polyesters, polylactide (PLA) comes under the area of environmentally degradable polymer materials. These are well suited for the preparation of disposable devices because of their biodegradability. The main characteristics of the PLA

**25**

*Clay Hybrid Materials*

compared to TPS alone [91].

ceramics, respectively.

those used for fusion.

and catalyst used [94].

**3. Conclusion and outlook**

inorganic hybrid materials [93].

*DOI: http://dx.doi.org/10.5772/intechopen.92529*

matrix are its easiness to degrade by the enzymatic or hydrolytic way. Hydrolytic degradation of PLA is a well-known process. Hydrolytic chains cleavage proceeds preferentially in amorphous regions, leading therefore to an increase of polymer global crystallinity. The formation of lactic acid oligomers, which directly follows from this chain scission, increases the –COOH end groups concentration in the medium. These carboxylic functions are known to catalyze the degradation reaction. Relative hydrophilicity of clay plays determining roles in the hydrolytic degradation process. More hydrophilic the filler, more pronounced is the degradation. Thermoplastic corn starch (TPS) clay hybrids showed enhanced biodegradation as

vi.Hyperbranched polymers: These polymers have a tree-like structure with a large number of branch points radiating from a multifunctional core molecule and hence a potentially high degree of end-group functionality per molecule. The –OH end groups are assumed to be concentrated in the periphery of the molecules in a hydrophilic environment. Polyester HBPs also show excellent processing char and shrinkage control. Dispersion of HBPs with various types of organically modified MMT in THF led to intercalation over the whole range of MMT contents and the layer expansion correlated with

the polarity of organic modifier rather than the size of HBPs [91].

have the promise of good internal bonding rubber phase due to the presence of

**Sol-gel hybrid materials:** This class of hybrids has received different names such as ORMOSILS and ORMOCERS, referring to organically modified silicates or

The technological importance of the sol-gel process is due to the simplicity in its preparation. Silicon alkoxides are the main precursors used in the synthesis of glasses and ceramics and they are also being used in the preparation of new organic-

A solution of the molecular precursor is transformed into a sol or a gel by a chemical reaction, resulting in a solid material upon evaporation. This transformation allows the production of materials with different possible compositions, intercalated microstructures, and chemical homogeneity at temperatures less than

Typical sol-gel processing variables leading to different morphologies of the materials are water to alkoxy and catalyst to alkoxy ratios and the type of solvent

Clay mineral poses a host of technical issues, such as dispersion of the inorganic filler in the polymer/base matrix. Better is the dispersion, better is the hybrid. Clay dispersed in natural dispersant renders the most thermally stable organoclay. Functionalization of clay surface for better compatibility with polymers is needed for the development of new synthetic layered materials with a wide range of properties. PAni/clay hybrids have been widely studied due to many advantages such as high optical contrast (%T), environmental stability, as well as comparatively low cost. However, the difficulties in processing PAni into films due to its very low solubility in most of the available solvents and the relatively poor mechanical properties decrease its performances and abilities in such applications. Green

surface functional groups, in addition to low initial viscosity [92].

HBPs with highly branched, 3D structure and high concentration of end groups

### *Clay Hybrid Materials DOI: http://dx.doi.org/10.5772/intechopen.92529*

*Clay Science and Technology*

ment of composite properties [80].

composite with modified clay [81].

composites [89].

improved fire performance [90].

very good compatibility with thermoplasticized starch.

MA as compatibilizer is used to enhance the possibility of intercalation of polymer between clay layers. The presence of MA increases the possibility of nanocomposite formation for PS, but this does not appear to help PP. PP/clay nanocomposites modified with the optimum level of compatibilizer yielded the greatest improve-

PE (polyethene) is another widely used polyolefin polymers. Alkylammonium ion facilitates interaction with polymer because it renders hydrophilic clay surface organophilic. Organically modified clay is not well dispersed in nonpolar PE as the nonpolar groups are too hydrophobic. Exfoliation and interaction behaviors depended on the hydrophilicity of PE grafted with MA and chain length of the organic modifier in the clay. When the number of methylene groups in alkyl amine (organic modifier) was larger than 16, exfoliated nanocomposites were obtained and the MA grafting levels was higher than about 0.1 wt% for the exfoliated nano-

Rubber is another such polymer. Carbon blacks are excellent reinforcers due to their strong interaction with rubbers, but they often decrease the processability of rubber compounds because of high viscosity at high volume loading. MMT exchanged with a liquid rubber (LR) is termed as LR-MMT for utilization of its favorable shape. Co-vulcanization of nitrile rubber was done with LR-MMT for the formation of the molecular composite. It has been studied that there exist strong rubber-filler interactions as (comparable to those in carbon black filled system) in LR MMT, in which negatively charged silicate layers are bonded to LR molecules

Polymers grafted on silicate surfaces also helps in delamination of its layers. It has been reported in the literature that PDMS (polydimethylsiloxane) grafted onto MMT layer surface via condensation of hydroxyl groups of PDMS and those hydroxyl

It has been observed that the photoluminescence quantum efficiency of conjugated polymer PE improves manifold in the presence of the inorganic phase like montmorillonite clay [82]. Incorporation of montmorillonite clays into conjugate polymers like PAni gives rise to hybrid/inorganic composites with special properties for application in organic light-emitting diodes (OLEDs), organic field-effect (OFETs), organic solar cells (OSCs), and electrochromic devices (ECDs) [83].

Intercalation of EPDM chains into OMMT galleries provided a strong interaction

iv.Fiber-reinforced polymers: Many fibers have been added as reinforcements to the polymer matrix. They are PS-Sisal fiber composites [84]. Bamboo polymer composites [85], short oxide fiber reinforced in kaolin [86], bamboo

Metal incorporated clay composites such as phosphorous clay composites show

Starch modified by grafting with vinyl monomers (e.g., methyl acrylate) onto the starch backbone yielded thermoplastic materials. Kaolin, a natural mineral, hydrated aluminosilicate, with high surface and presence of polar groups showed

Aliphatic polyesters, polylactide (PLA) comes under the area of environmentally degradable polymer materials. These are well suited for the preparation of disposable devices because of their biodegradability. The main characteristics of the PLA

glass-reinforced in PP [87], thermoplastic starch [88], switchgrass.

v.Biodegradable-polymers: These include biodegradable resin clay

groups on MMT layers prevents the nanolayers of MMT from reaggregating.

with positively charged terminal sites forming "bound rubber."

between EPDM and OMMT sheets in exfoliated composites.

**24**

matrix are its easiness to degrade by the enzymatic or hydrolytic way. Hydrolytic degradation of PLA is a well-known process. Hydrolytic chains cleavage proceeds preferentially in amorphous regions, leading therefore to an increase of polymer global crystallinity. The formation of lactic acid oligomers, which directly follows from this chain scission, increases the –COOH end groups concentration in the medium. These carboxylic functions are known to catalyze the degradation reaction. Relative hydrophilicity of clay plays determining roles in the hydrolytic degradation process. More hydrophilic the filler, more pronounced is the degradation. Thermoplastic corn starch (TPS) clay hybrids showed enhanced biodegradation as compared to TPS alone [91].

vi.Hyperbranched polymers: These polymers have a tree-like structure with a large number of branch points radiating from a multifunctional core molecule and hence a potentially high degree of end-group functionality per molecule. The –OH end groups are assumed to be concentrated in the periphery of the molecules in a hydrophilic environment. Polyester HBPs also show excellent processing char and shrinkage control. Dispersion of HBPs with various types of organically modified MMT in THF led to intercalation over the whole range of MMT contents and the layer expansion correlated with the polarity of organic modifier rather than the size of HBPs [91].

HBPs with highly branched, 3D structure and high concentration of end groups have the promise of good internal bonding rubber phase due to the presence of surface functional groups, in addition to low initial viscosity [92].

**Sol-gel hybrid materials:** This class of hybrids has received different names such as ORMOSILS and ORMOCERS, referring to organically modified silicates or ceramics, respectively.

The technological importance of the sol-gel process is due to the simplicity in its preparation. Silicon alkoxides are the main precursors used in the synthesis of glasses and ceramics and they are also being used in the preparation of new organicinorganic hybrid materials [93].

A solution of the molecular precursor is transformed into a sol or a gel by a chemical reaction, resulting in a solid material upon evaporation. This transformation allows the production of materials with different possible compositions, intercalated microstructures, and chemical homogeneity at temperatures less than those used for fusion.

Typical sol-gel processing variables leading to different morphologies of the materials are water to alkoxy and catalyst to alkoxy ratios and the type of solvent and catalyst used [94].

### **3. Conclusion and outlook**

Clay mineral poses a host of technical issues, such as dispersion of the inorganic filler in the polymer/base matrix. Better is the dispersion, better is the hybrid. Clay dispersed in natural dispersant renders the most thermally stable organoclay.

Functionalization of clay surface for better compatibility with polymers is needed for the development of new synthetic layered materials with a wide range of properties. PAni/clay hybrids have been widely studied due to many advantages such as high optical contrast (%T), environmental stability, as well as comparatively low cost. However, the difficulties in processing PAni into films due to its very low solubility in most of the available solvents and the relatively poor mechanical properties decrease its performances and abilities in such applications. Green

hybrids reinforced with natural fibers and macromolecules have pronounced biodegradable and recyclable properties and thus emerge as better packaging materials.

Current research focuses on the use of advanced nanotech catalysts and materials for the purification/remediation of contaminated surface or groundwater and municipal water or industrial wastewater. Though clay hybrids have been extensively used as nano adsorbents for the removal of heavy metals, As, and dyes from wastewater, its fabrication as inorganic membranes have received limited attention in the literature. Titania pillared clay, an important class of layered materials, exhibits unique surface charge characteristics that make them a good candidate for removal of organics from wastewater by just adjusting the pH of the solution. Development of such membrane reactors integrating the separation process with photocatalysis would lead to an important new technological application that would add economic value to the vast natural deposits of clay minerals located worldwide. However, membrane fouling is still a critical problem that results in flux decline with time, needs to be addressed. In a nutshell, the outlook is bright and sustainable for clay hybrid materials.

### **Abbreviations**


**27**

**Author details**

Tanushree Choudhury

Chemistry Division, VIT Chennai, Chennai, India

provided the original work is properly cited.

\*Address all correspondence to: tanushree.c@vit.ac.in

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Clay Hybrid Materials*

DEP resin

PS polystyrene NCH nylon clay hybrid PBI polybenzoimidazole OMT organo montmorillonite

THF tetrahydrofuran MeOH methanol

OFET organo field effect OSC organic solar cell ECD electrochromic device TPS thermoplastic corn starch ORMOSIL organo modified silicate ORMOCERS organo modified ceramics

*DOI: http://dx.doi.org/10.5772/intechopen.92529*

PCN polymer clay nanocomposites

OLED organo light emitting diode

MAO methylaluminoxane TMA trimethylalkoxide PAni polyaniline PCL polycaprolactum PHA polyhydroxyalkanoate PBS polybutylene succinate *Clay Hybrid Materials DOI: http://dx.doi.org/10.5772/intechopen.92529*

*Clay Science and Technology*

for clay hybrid materials.

MMT montmorillonite VA vinyl acetate EVA ethyl vinyl acetate PVA polyvinyl alcohol

PA polyamide PU polyurethane

PI polyimide

PAA polyamic acid

PO polyolefin oligomer PP polypropylene MA maleic anhydride PE polyethylene LR liquid rubber

PDMS polydimethylsiloxane

HBP hyperbranched polymer

PMMA polymethyl methacrylate

OMS organomethylsilicate PAM polyacrylamide EVOH ethylvinylalcohol

mPE metallocene blended polyethylene

PPCN polypropylene clay nanocomposites

PLA polylactide

AN acrylonitrile

ABS acrylonitrile butadiene styrene PET poly (ethyl terephthalate) HENA hydroxyethyl iso-nicotinamide SAN styrene-co-acrylonitrile

OMT organic montmorillonite

CTE co-efficient of thermal expansion

DSDM-MT distearylammonium montmorillonite

EPDM ethylene propylene diene methylene linkage rubber

DGEBA diglycidyl ether bisphenol A CEC cation exchange capacity

**Abbreviations**

hybrids reinforced with natural fibers and macromolecules have pronounced biodegradable and recyclable properties and thus emerge as better packaging materials. Current research focuses on the use of advanced nanotech catalysts and materials for the purification/remediation of contaminated surface or groundwater and municipal water or industrial wastewater. Though clay hybrids have been extensively used as nano adsorbents for the removal of heavy metals, As, and dyes from wastewater, its fabrication as inorganic membranes have received limited attention in the literature. Titania pillared clay, an important class of layered materials, exhibits unique surface charge characteristics that make them a good candidate for removal of organics from wastewater by just adjusting the pH of the solution. Development of such membrane reactors integrating the separation process with photocatalysis would lead to an important new technological application that would add economic value to the vast natural deposits of clay minerals located worldwide. However, membrane fouling is still a critical problem that results in flux decline with time, needs to be addressed. In a nutshell, the outlook is bright and sustainable

**26**


### **Author details**

Tanushree Choudhury Chemistry Division, VIT Chennai, Chennai, India

\*Address all correspondence to: tanushree.c@vit.ac.in

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[84] Manickandan Nair KC, Thomas S. Interface modification on the mechanical properties of PS-sisal composites. Polymer Composites. 2003;**24**(3):332-343

[85] Saxena M, Gauri VS. Studies on bamboo polymer composites. Polymer Composites. 2003;**24**(3):428-436

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[87] Thwe MM, Liao K. Environmental effects on bamboo-glass/PP hybrid composites. Journal of Materials Science. 2003;**38**:363-376

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[93] Nassar EJ, Neri CR, Cale EPS, Serra OA. Functionalised silica synthesized by sol-gel process. Journal of Non-Crystalline Solids. 1999;**247**:124-128

[94] Kickelbick G. Concepts for the incorporation of inorganic building blocks into organic polymers on a nanoscale. Progress in Polymer Science. 2003;**28**:83-114

**33**

tioned before.

**Chapter 3**

Treatments

fied phases. Starting vermiculites with high K+

*Celia Marcos*

**1. Introduction**

between 2.4 and 2.7 g/cm3

groups. In addition, it contains water.

.

**Abstract**

Structural Changes in Vermiculites

Induced by Temperature, Pressure,

Depending on the treatment, the crystallinity increase of vermiculite may be accompanied by the enhancement of the majority starting phase, and the crystallinity loss may be accompanied by the appearance or disappearance of interstrati-

interstratified phases and lower water content and are less crystalline. The crystallinity loss of vermiculite and therefore the structural disorder increase are caused by the structural water loss. On the contrary, the crystallinity increase is produced by water gain. The vermiculite transformation by structural water loss occurs with temperature increase, vacuum, irradiation with microwaves or ultraviolet, and alcohol or acidic treatment. On the contrary, the transformation by water gain occurs in vermiculites treated with hydrogen peroxide and in those subjected to ionic metal exchange. These treatments provide evaluable information on the relationship between the structure of vermiculites and their industrial applications. The changes suffered by vermiculites due to the treatments applied could give light to ambiguities about their geological origin and hydrothermal and/or supergene processes.

**Keywords:** vermiculite, structural changes, physical and chemical treatments

Vermiculite is a mineral that belongs to the phyllosilicate subclass of the silicate class. It has an appearance similar to micas at macroscopic level (**Figure 1**), with varied colors (green, yellow, to brown), leafy habit, hardness about 2, and a density

Its structure (**Figure 2**) corresponds to that of the 2:1 group [1], which is composed of two T-O-T layers joined by an interlayer. The T-O-T layer is composed of an octahedral (O) sheet of Mg2+, located between two tetrahedral sheets (T) of Si4+. The interlayer is formed by an octahedral sheet of Mg2+ bound to oxygens or OH<sup>−</sup>

In vermiculite, isomorphic substitutions, especially in the tetrahedral sheets of Si4+ to Al3+, are very common. As a consequence of the positive charge difference, compensation occurs with cations in the interlayer space, mainly Mg2+, as men-

content in the interlayer have more

Irradiation, and Chemical

### **Chapter 3**

*Clay Science and Technology*

2003;**44**:7709-7719

2004;**23**:217-223

2003;**22**:217-223

2006;**91**:103-113

2001;**42**:9819-9826

2013;**49**(8):2186-2195

2003;**24**(3):332-343

[84] Manickandan Nair KC,

of in-situ blended metallocene PE clay nanocomposites. Polymer.

[86] Papargyri SA, Cooke RG, Papargyris DA, Botis A,

Science. 2003;**38**:363-376

Agnelli JAM. Composites of thermoplastic starch and kaolin.

biodegradable resin/clay

[90] Hussain M, Simon GP. Phosphorous-clay polymer

2003;**22**:1471-1475

2004;**45**:949-960

1999;**247**:124-128

2003;**28**:83-114

[92] Ratna D, Becker O, Krishnamurthy R, Simon GP, Varley RJ. Nanocomposites based on a combination of epoxy resin, hyperbranched epoxy, and a layered silicate. Polymer. 2003;**44**:7449-7457

Papapolmeron G, Papargyris AD. Kaolin clay matrix composites. British Ceramic Transactions. 2003;**102**(5):193-203

[87] Thwe MM, Liao K. Environmental effects on bamboo-glass/PP hybrid composites. Journal of Materials

[88] De Carvallo AJF, Curvello AAS,

Carbohydrate Polymers. 2001;**45**:189-194

[89] Okada K, Mitsunaga T, Nagase Y. Properties and particle dispersion of

nanocomposites for fire performance. Journal of Materials Science Letters.

[91] Rodlert M, Christopher JG, Garamszegi L, Leterrier Y, Grunbauer HJM, Manson J-AE. Hyperbranched polymer/ MMT clay nanocomposites. Polymer.

[93] Nassar EJ, Neri CR, Cale EPS, Serra OA. Functionalised silica synthesized by sol-gel process. Journal of Non-Crystalline Solids.

[94] Kickelbick G. Concepts for the incorporation of inorganic building blocks into organic polymers on a nanoscale. Progress in Polymer Science.

nanocomposites. Korea-Australia Rheology Journal. 2003;**15**(1):43-50

[77] Shin SYA, Simon LC, Soares JBP, Scholz G. PE clay hybrid nanocomposites.

Polymer. 2003;**44**:5317-5321

[78] Zheng H, Zhang Y, Peng Z,

nanocomposites. Polymer Testing.

[79] Li J, Zhou C, Gang W. Study on nonisothermal crystallization of maleic anhydride grafted PP/MMT nanocomposite. Polymer Testing.

[80] Zheng X, Jiang DD, Wilkie CA. Polystyrene nanocomposites based on an oligomerically modified clay containing maleic anhydride. Polymer Degradation and Stability.

[81] Wang KH, Choi MH, Koo CM, Choi YS, Chung IJ. Synthesis & characterisation of maleated PE/ clay nanocomposites. Polymer.

[82] Chao Chen Em M et al. PE/clay hybrid materials: A simple method to modulate the optical properties. Polimeros. 2016;**26**(1):38-43

[83] Teichler A et al. Inkjet printing of chemically tailored light emitting polymers. European Polymer Journal.

Thomas S. Interface modification on the mechanical properties of PS-sisal composites. Polymer Composites.

[85] Saxena M, Gauri VS. Studies on bamboo polymer composites. Polymer Composites. 2003;**24**(3):428-436

Zhang Y. Influence of clay modification on the structure and mechanical properties of EPDM MMT

**32**

## Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation, and Chemical Treatments

*Celia Marcos*

### **Abstract**

Depending on the treatment, the crystallinity increase of vermiculite may be accompanied by the enhancement of the majority starting phase, and the crystallinity loss may be accompanied by the appearance or disappearance of interstratified phases. Starting vermiculites with high K+ content in the interlayer have more interstratified phases and lower water content and are less crystalline. The crystallinity loss of vermiculite and therefore the structural disorder increase are caused by the structural water loss. On the contrary, the crystallinity increase is produced by water gain. The vermiculite transformation by structural water loss occurs with temperature increase, vacuum, irradiation with microwaves or ultraviolet, and alcohol or acidic treatment. On the contrary, the transformation by water gain occurs in vermiculites treated with hydrogen peroxide and in those subjected to ionic metal exchange. These treatments provide evaluable information on the relationship between the structure of vermiculites and their industrial applications. The changes suffered by vermiculites due to the treatments applied could give light to ambiguities about their geological origin and hydrothermal and/or supergene processes.

**Keywords:** vermiculite, structural changes, physical and chemical treatments

### **1. Introduction**

Vermiculite is a mineral that belongs to the phyllosilicate subclass of the silicate class. It has an appearance similar to micas at macroscopic level (**Figure 1**), with varied colors (green, yellow, to brown), leafy habit, hardness about 2, and a density between 2.4 and 2.7 g/cm3 .

Its structure (**Figure 2**) corresponds to that of the 2:1 group [1], which is composed of two T-O-T layers joined by an interlayer. The T-O-T layer is composed of an octahedral (O) sheet of Mg2+, located between two tetrahedral sheets (T) of Si4+. The interlayer is formed by an octahedral sheet of Mg2+ bound to oxygens or OH<sup>−</sup> groups. In addition, it contains water.

In vermiculite, isomorphic substitutions, especially in the tetrahedral sheets of Si4+ to Al3+, are very common. As a consequence of the positive charge difference, compensation occurs with cations in the interlayer space, mainly Mg2+, as mentioned before.

**Figure 1.** *Vermiculite appearance in hand sample.*

**Figure 2.** *Vermiculite structure.*

This structure, with spatial group C2/c, is generally disordered [2], that is, it shows stacking defects that alter the regular alternation of the layers parallel to crystallographic axis b (**Figure 3**).

Due to the presence of water and OH<sup>−</sup> groups, vermiculite can undergo hydration-dehydration processes that depend on various factors such as temperature, pressure, particle size, relative humidity, and chemical composition [1, 3–10].

The hydration state of vermiculites is defined by the number of layers of water in the interlayer space, with phases having zero, one, and two water layers. These phases were named by [11] as 0-WLHS (state of hydration with 0 water layers), 1-WLHS (state of hydration with 1 water layer), and 2-WLHS (state of hydration with 2 water layers), respectively. As an example, for Mg-vermiculite the basal distances are 9.02 Ǻ for 0-WLHS, 11.50 Ǻ for 1-WLHS, and 14.40 Ǻ for 2-WLHS [9–12].

The chemical formula of vermiculite is X4(Y2–3)O10(OH)2M,nH2O, where X represents the tetrahedral positions (Si4+ y Al3+), Y the octahedral positions (Mg2+, Fe2+, Fe3+, Cr3+, Ti4+, etc.), and M the cations located in the interlayer space (Mg2+, Ca2+, K+ , Na+ , etc.) to compensate the charges, as a consequence of the isomorphic substitutions.

In addition to the described mineral that corresponds to vermiculite in the strict sense, there are the so-called commercial vermiculites. These vermiculites consist of various interstratified of mica/vermiculite, vermiculite with different states of hydration, mixtures of mica and vermiculite, etc. The distribution of the different phases would be mosaic-type (**Figure 4**).

The main characteristic of commercial vermiculites is their exfoliation and expansion capacity when the vermiculite is abruptly heated, and that occurs due to the loss of water molecules located between the silicate sheets (**Figure 5**).

**35**

**Figure 5.**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

*Mosaic distribution of different phases in a commercial vermiculite (modified from Hillier et al. [15], with* 

*Exfoliation mechanism scheme of a commercial vermiculite when heated at 1000°C for 1 minute;* 

*(c) and (d) modified from Hillier et al. [15] with permission.*

*(a) commercial vermiculite; (b) exfoliated commercial vermiculite; (c) scheme of the arrangement in domains of the different intergrowth phases in a particle of a commercial vermiculite; (d) diagram of the exfoliated particle; (e) structure of an ideal vermiculite; (f) structure of the exfoliated ideal vermiculite. Note: Schemes* 

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

*Disordered layers in the vermiculite structure.*

**Figure 3.**

**Figure 4.**

*permission).*

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

**Figure 3.** *Disordered layers in the vermiculite structure.*

### **Figure 4.**

*Clay Science and Technology*

*Vermiculite appearance in hand sample.*

**Figure 1.**

**Figure 2.**

*Vermiculite structure.*

crystallographic axis b (**Figure 3**).

This structure, with spatial group C2/c, is generally disordered [2], that is, it shows stacking defects that alter the regular alternation of the layers parallel to

Due to the presence of water and OH<sup>−</sup> groups, vermiculite can undergo hydration-dehydration processes that depend on various factors such as temperature, pressure, particle size, relative humidity, and chemical composition [1, 3–10]. The hydration state of vermiculites is defined by the number of layers of water in the interlayer space, with phases having zero, one, and two water layers. These phases were named by [11] as 0-WLHS (state of hydration with 0 water layers), 1-WLHS (state of hydration with 1 water layer), and 2-WLHS (state of hydration with 2 water layers), respectively. As an example, for Mg-vermiculite the basal distances are 9.02 Ǻ for 0-WLHS, 11.50 Ǻ for 1-WLHS, and 14.40 Ǻ for 2-WLHS [9–12]. The chemical formula of vermiculite is X4(Y2–3)O10(OH)2M,nH2O, where X represents the tetrahedral positions (Si4+ y Al3+), Y the octahedral positions (Mg2+, Fe2+, Fe3+, Cr3+, Ti4+, etc.), and M the cations located in the interlayer space (Mg2+,

, etc.) to compensate the charges, as a consequence of the isomorphic

In addition to the described mineral that corresponds to vermiculite in the strict sense, there are the so-called commercial vermiculites. These vermiculites consist of various interstratified of mica/vermiculite, vermiculite with different states of hydration, mixtures of mica and vermiculite, etc. The distribution of the different

The main characteristic of commercial vermiculites is their exfoliation and expansion capacity when the vermiculite is abruptly heated, and that occurs due to

the loss of water molecules located between the silicate sheets (**Figure 5**).

**34**

Ca2+, K+

substitutions.

, Na+

phases would be mosaic-type (**Figure 4**).

*Mosaic distribution of different phases in a commercial vermiculite (modified from Hillier et al. [15], with permission).*

### **Figure 5.**

*Exfoliation mechanism scheme of a commercial vermiculite when heated at 1000°C for 1 minute; (a) commercial vermiculite; (b) exfoliated commercial vermiculite; (c) scheme of the arrangement in domains of the different intergrowth phases in a particle of a commercial vermiculite; (d) diagram of the exfoliated particle; (e) structure of an ideal vermiculite; (f) structure of the exfoliated ideal vermiculite. Note: Schemes (c) and (d) modified from Hillier et al. [15] with permission.*

Authors such as [13] and later [14] found that the greatest exfoliation is achieved in the case of regular mica-vermiculite interstratified. Couderc and Douillet [14] associated this fact with the collision, during the "thermal shock," of the water molecules of the vermiculite sheets with the mica sheets, producing a greater separation between them; Hillier [15] related exfoliation with the mosaic distribution of the different mineral phases within the vermiculite particles. Lateral phase boundaries between vermiculite and other phases (mica, or vermiculite, and chlorite) would prevent vapor from escaping from a particle, resulting in exfoliation when the pressure exceeds the bonding forces that hold the layers together. This type of thermal exfoliation is the oldest and the one that is still used today mostly in the industry.

Vermiculites can be modified by changes in temperature and pressure, chemical treatments, and irradiation, causing physical and structural changes in the mineral [16–24].

One of the most notable physical changes is exfoliation and expansion, which are influenced by factors such as water content, type of cations of the interlayer, and interstratifications of vermiculite [10, 17, 25].

Unmodified and modified commercial vermiculites are characterized by their industrial and technological applications [26–35]. These applications are a function of its physical and chemical properties and the treatment it has undergone, for example, thermal and acoustic insulation, adsorbent of substances, refractories, fire protection, support for hydroponic crops, light concretes, etc. The synthesis of advanced materials such as new glasses of great technological interest constitutes an example of the uses based on chemical applications. Numerous studies on the intercalation of polar organic molecules by clay minerals have been carried out. In addition to water, inorganic or organic substances can be adsorbed in the expandable interlayer space [36, 37].

The objective of this research has been to show the structural changes in commercial vermiculites induced by temperature, pressure, irradiation and chemical treatments, the relationship between these treatments, and crystallinity and the possible causes.

### **2. Methodology**

### **2.1 Materials**

The investigated vermiculite samples come from Catalão (Goiás, Brazil), Paulistana (Piauí, Brazil), China, Libby (Montana, USA), Benahavis (Málaga, Spain), and Sta. Olalla (Huelva, Spain) to compare. Vermiculite from Catalão (hereinafter Goiás) is associated with an ultramafic complex; Paulistana's vermiculite (hereinafter Piauí) is found in a hybrid basic rock, probably a lamprophyre [38]. The origin of China's vermiculites is unknown. The origin and mineralogy of the vermiculite of Sta. Olalla have been extensively studied [39–42]. This vermiculite is formed from phlogopite as a result of the alteration of pyroxenites. Vermiculite from Benahavis occurs in elongated veins, and the host rock is mainly serpentine [43, 44] and can be considered formed by alteration of phlogopite [45].

The weight percent of element oxides of the vermiculites considered in this chapter [10, 46] is in **Table 1** and their water content (%) in **Table 2**.

### **2.2 Vermiculite treatments**

### *2.2.1 Heat treatment*

For the experiments with heat [10, 23], two diffractometers were used: Seifert XRD 3000 diffractometer (Scientific-Technical Services of the University of

**37**

or Mg2+ and K+

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

SiO2 35.9 37.0 39.9 40.7 43.2 35.6 41.1 38.7 TiO2 0.3 2.5 1.1 0.8 1.0 1.2 1.2 1.2 Al2O3 15.8 14.1 9.3 11.5 11.9 11.0 10.0 13.0 Cr2O3 0.0 0.0 0.1 0.0 0.2 0.4 0.0 1.0 FeO 3.3 7.6 6.7 9.6 4.3 4.6 7.9 8.6 MnO 0.1 0.1 0.0 0.1 0.0 0.0 0.0 0.1 MgO 24.1 21.9 25.5 18.0 24.3 21.8 23.3 20.6 CaO 0.3 0.1 0.2 0.0 0.4 0.9 0.2 0.0 Na2O 0.1 0.1 0.0 0.1 0.7 3.5 0.1 0.3 NiO 0.0 0.1 0.0 0.0 0.0 0.1 0.1 0.0 K2O 0.0 0.0 3.5 1.1 7.5 5.6 6.0 9.7

**Benahavis1 Piauí1 Goiás1 China W1 China G1 Palabora1 Libby2**

Oviedo) at 30 mA and 40 kV; Cu-Kα radiation, λ = 1.5418 Å; 2θ range of 3–20°; 2° scans of 0.02° per step; and a count time of 20 s per step and Bruker AXS diffractometer (Plasma Physics Laboratory, National University, Manizales headquarters) at 30 mA and 40 kV (Cu-Kα radiation; λ = 1.5418 Å), 2θ range of 3–40°, 2θ scans of

With an increase of T, the behavior of the vermiculites was different depending on the composition of the vermiculite and the type of heating (ex situ or in situ). The result with heating ex situ at 1000°C for 1 minute was an expanded and exfoliated light product composed of enstatite in the purest vermiculites (with Mg2+

and/or Na+

The diffraction patterns made with temperature increase (40–140°C) in situ using the Seifert XRD 3000 equipment, and a powder sample showed the coexistence of the 2-WLHS phases with two layers and one layer of water, and the 1-WLHS phase was revealed. In the patterns made with the Bruker AXS

exfoliation of the latter was much greater than that of the former.

Sta. Olalla1 25.6 Piauí1 14.0 Goiás1 13.6 China O1 17.6 China G1 12.3 Palabora1 13.4 Libby2 10.3

in the interlayer) Sta. Olalla and Benahavis and mica and enstatite in

and/or Ca2+ in the interlayer). The

**Water content (%)**

0.1°, and a count time of 20 s per step.

the commercial vermiculites (with K+

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

**Sample Sta.** 

*1*

*2*

*1*

*2*

**Table 2.** *Water content (%).*

*Marcos et al. [9].*

*Marcos and Rodríguez [46].*

**Table 1.**

*Marcos et al. [9].*

*Marcos and Rodríguez [46].*

*Weight percent of element oxides.*

**Olalla1**


*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

### **Table 1.**

*Clay Science and Technology*

[16–24].

**2. Methodology**

**2.2 Vermiculite treatments**

*2.2.1 Heat treatment*

**2.1 Materials**

interstratifications of vermiculite [10, 17, 25].

Authors such as [13] and later [14] found that the greatest exfoliation is achieved in the case of regular mica-vermiculite interstratified. Couderc and Douillet [14] associated this fact with the collision, during the "thermal shock," of the water molecules of the vermiculite sheets with the mica sheets, producing a greater separation between them; Hillier [15] related exfoliation with the mosaic distribution of the different mineral phases within the vermiculite particles. Lateral phase boundaries between vermiculite and other phases (mica, or vermiculite, and chlorite) would prevent vapor from escaping from a particle, resulting in exfoliation when the pressure exceeds the bonding forces that hold the layers together. This type of thermal exfoliation is the oldest and the one that is still used today mostly in the industry. Vermiculites can be modified by changes in temperature and pressure, chemical treatments, and irradiation, causing physical and structural changes in the mineral

One of the most notable physical changes is exfoliation and expansion, which are influenced by factors such as water content, type of cations of the interlayer, and

The objective of this research has been to show the structural changes in commercial vermiculites induced by temperature, pressure, irradiation and chemical treatments, the relationship between these treatments, and crystallinity and the possible causes.

The investigated vermiculite samples come from Catalão (Goiás, Brazil), Paulistana (Piauí, Brazil), China, Libby (Montana, USA), Benahavis (Málaga, Spain), and Sta. Olalla (Huelva, Spain) to compare. Vermiculite from Catalão (hereinafter Goiás) is associated with an ultramafic complex; Paulistana's vermiculite (hereinafter Piauí) is found in a hybrid basic rock, probably a lamprophyre [38]. The origin of China's vermiculites is unknown. The origin and mineralogy of the vermiculite of Sta. Olalla have been extensively studied [39–42]. This vermiculite is formed from phlogopite as a result of the alteration of pyroxenites. Vermiculite from Benahavis occurs in elongated veins, and the host rock is mainly serpentine

[43, 44] and can be considered formed by alteration of phlogopite [45].

chapter [10, 46] is in **Table 1** and their water content (%) in **Table 2**.

The weight percent of element oxides of the vermiculites considered in this

For the experiments with heat [10, 23], two diffractometers were used: Seifert

XRD 3000 diffractometer (Scientific-Technical Services of the University of

Unmodified and modified commercial vermiculites are characterized by their industrial and technological applications [26–35]. These applications are a function of its physical and chemical properties and the treatment it has undergone, for example, thermal and acoustic insulation, adsorbent of substances, refractories, fire protection, support for hydroponic crops, light concretes, etc. The synthesis of advanced materials such as new glasses of great technological interest constitutes an example of the uses based on chemical applications. Numerous studies on the intercalation of polar organic molecules by clay minerals have been carried out. In addition to water, inorganic or organic substances can be adsorbed in the expandable interlayer space [36, 37].

**36**

*Weight percent of element oxides.*


**Table 2.**

*Water content (%).*

*Marcos and Rodríguez [46].*

Oviedo) at 30 mA and 40 kV; Cu-Kα radiation, λ = 1.5418 Å; 2θ range of 3–20°; 2° scans of 0.02° per step; and a count time of 20 s per step and Bruker AXS diffractometer (Plasma Physics Laboratory, National University, Manizales headquarters) at 30 mA and 40 kV (Cu-Kα radiation; λ = 1.5418 Å), 2θ range of 3–40°, 2θ scans of 0.1°, and a count time of 20 s per step.

With an increase of T, the behavior of the vermiculites was different depending on the composition of the vermiculite and the type of heating (ex situ or in situ).

The result with heating ex situ at 1000°C for 1 minute was an expanded and exfoliated light product composed of enstatite in the purest vermiculites (with Mg2+ or Mg2+ and K+ in the interlayer) Sta. Olalla and Benahavis and mica and enstatite in the commercial vermiculites (with K<sup>+</sup> and/or Na+ and/or Ca2+ in the interlayer). The exfoliation of the latter was much greater than that of the former.

The diffraction patterns made with temperature increase (40–140°C) in situ using the Seifert XRD 3000 equipment, and a powder sample showed the coexistence of the 2-WLHS phases with two layers and one layer of water, and the 1-WLHS phase was revealed. In the patterns made with the Bruker AXS

diffractometer, the last phase did not appear, and it was observed that the structure practically collapsed at 100°C, phase 1-WLHS reappearing as temperature increases.

With gradual increase in T in situ, dehydration of the vermiculites could be observed until practically reaching collapse, although the behavior was different depending on whether the samples contained Mg2+ or Mg2+ and K+ in the interlayer or K+ and/or Na+ and/or Ca2+. In the former dehydration appears to be restricted to 1-WLHS, and dehydroxylation begins at lower temperatures and is faster than in the latter, in which already dehydrated vermiculite coexists with a similar structure to mica.

### *2.2.2 Pressure treatment*

The experiments at atmospheric pressure P = 1.4⋅10<sup>−</sup><sup>2</sup> mbar and P = 2.4⋅10<sup>−</sup><sup>4</sup> mbar were carried out on both powder samples and exfoliation flakes of three vermiculites from Sta. Olalla (Huelva, Spain), Paulistana (Piauí, Brazil), and Western China [9]. A Seifert XRD 3000 diffractometer from the Scientific-Technical Services of the University of Oviedo was used. The conditions of use were 30 mA and 40 kV (Cu-Kα radiation, λ = 1.5418 Å), range 2θ between 2 and 70°2θ, speed 0.02°2θ/20 s. Two commercial Leybold pumps (Trivac D 2.5 E (up to 10–2 mbar) and Turbovac TMP 50 (up to 10–4 mbar)) were used for the vacuum experiments.

The effect of vacuum, like that of temperature, causes dehydration of vermiculite but with a different evolution through the different states of hydration. In fact, under vacuum, the process appears to inhibit itself to a state of hydration with one layer of water (1-WLHS). The role of T is inhibited against that of pressure. The Sta. Olalla vermiculite gave rise to the formation of three different interstratified phases: two phases characterized by an interstratification with interplanar distances, *d* = 11.5–13.8 Å and *d* = 9.6–11.5 Å, respectively, and another phase with *d* = 13.8 Å.

Under vacuum, P = 1.4⋅10<sup>−</sup><sup>2</sup> mbar, in the Sta. Olalla, vermiculite phase 2-WLHS was observed with two layers of water coexisting with phase 2-WLHS but with a layer of water. In Piauí vermiculite, the evolution of the most characteristic reflection was more remarkable since it disappears, appearing in phase 1-WLHS.

The effect was faster with powder samples, and phase 2-WLHS quickly transforms to phase 1-WLHS.

### *2.2.3 Irradiation treatment*

### *2.2.3.1 Microwave irradiation*

The transformations undergone by the vermiculites subjected to microwave irradiation (at 800 W and exposure times from 10 to 20 s) were characterized by X-ray diffraction [24]. A PHILIPS X'PERT PRO X-ray diffractometer was used, at 40 mA and 45 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–70°2θ, steps of 0.02°, and a count time 1 s per step.

Microwave irradiation of vermiculite samples caused much less water loss than they do when subjected to sudden high-temperature heating; it also caused exfoliation of the material. From a structural point of view, the X-ray diffraction patterns of the vermiculites of Sta. Olalla, China, and Libby showed loss of crystallinity and disorder.

### *2.2.3.2 Ultraviolet irradiation*

The changes induced by ultraviolet (UV), short wave (254 nm), and long (356 nm) radiation at different times (1 hour, 1 day, and 1 week) in vermiculites from Sta. Olalla, Libby, and China were studied by using X-ray diffraction [46]. A PHILIPS X'PERT PRO X-ray diffractometer was used, at 40 mA and 45 kV,

**39**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

Cu-Kα radiation (λ = 1.5418 Å), range of 3–10°2θ, steps of 0.007°, and a count time 1 s per step. Crystallite size and structural deformation were evaluated using

In the powder samples of Sta. Olalla, Libby, and China, a decrease in the intensity of the most characteristic reflections was observed as well as a decrease in the size of the crystallite and an increase in deformation. The results were more significant for powder vermiculite from China than for Sta. Olalla and Libby vermiculites, probably due to the coexistence of different hydration states, interstratifications, and superstructures in the initial vermiculite in China. The water loss in these long and short UV irradiated samples for 168 hours was 4 and 4.5% for the Sta. Olalla sample, 0.9 and 1% for the Chinese sample, and 6.4 and 7% for the Libby sample. In the exfoliation flake samples, an increase in the intensity of the most characteristic reflection is observed, in addition to a larger crystallite size and a lower percentage

By **ion exchange of metals** (Ni2+, Fe2+, Fe3+) for the Mg2+ of the interlayer in the

In the case of nickel [35], an aqueous solution of Ni2+ acetate was used, and in the case of iron [47], FeCl2 and FeCl3 solutions were used. The crystal structures of the nickel and iron vermiculites were refined using the DIFFaX+ program [48] (and a later version). The characterization was carried out with X-ray diffraction by transmission using an InEL XRD RG3000 cobalt tube vertical diffractometer (λ = 1.7890 Å) (40 kV, 35 mA) and an InEL CPS 120 detector, in the 2θ range of 4–70° (step 0.03°, total acquisition time of 5400 s). Refinement confirmed the similarity of the Ni2+-, Fe2+-, and Fe3+-vermiculites with the Mg-vermiculite. In the Fe2+-vermiculite reflections corresponding to the akaganeite (β-FeOOH) (JCPDS card 01–075-1594), a phase that was corroborated by Mössbauer spectroscopy (16%) was observed, a technique that also allowed showing the presence of said phase (3%) in the Fe3+-vermiculite. Only vermiculite was detected in the Ni2+ vermiculites obtained from the starting vermiculite, while in the one obtained from the homoionized starting vermiculite (with brucite -Mg (OH)2<sup>−</sup>), a brucite phase with magnesium and nickel was also detected. In this refinement it was found that Ni2+ and Fe2+ also enter the octahedral layer, although there was no evidence for Fe3+.

Nitric acid treatment at 4 and 8 M was used at room temperature and different treatment times on the purest vermiculite from Sta. Olalla and two commercial vermiculites from Goiás and China, respectively [49]. To quantify potential loss of mass or water, 1 mL of each sample was weighed pre- and post-acidic treatment, and their volume post-treatment was measured. To identify any structural change, X-ray diffraction patterns were taken with a PANalytical X'pertPro diffractometer using 40 mA and 45 kV (Cu-Kα radiation; λ = 1.5418 Å), 2θ scans 5–35o, 2θ step scans of 0.007°, and a counting time of 1 s per step. TEM high-resolution microscope with a resolution of 1.9 Å between points and 1.0 Å between lines was used to obtain TEM and selected area electron diffraction (SAED) micrographs with its

Vermiculites treated with acid suffered (a) slight delamination and color (**Figure 6**); (b) weight loss (**Table 3**) due to the mass and water loss; (c) inhomogeneous cation leaching, probably achieved to transfer iron from those octahedral sheets to clusters deposited on vermiculite layers (**Figure 7**) [50–53] (and in the samples with

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

of deformation, so that the crystallinity increased.

vermiculite-Mg of Sta. Olalla (Huelva, Spain).

PANalytical software (X'Pert Plus).

*2.2.4 Chemical treatment*

*2.2.4.1 Acid activation with HNO3*

accompanied CCD camera (Gatan).

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

Cu-Kα radiation (λ = 1.5418 Å), range of 3–10°2θ, steps of 0.007°, and a count time 1 s per step. Crystallite size and structural deformation were evaluated using PANalytical software (X'Pert Plus).

In the powder samples of Sta. Olalla, Libby, and China, a decrease in the intensity of the most characteristic reflections was observed as well as a decrease in the size of the crystallite and an increase in deformation. The results were more significant for powder vermiculite from China than for Sta. Olalla and Libby vermiculites, probably due to the coexistence of different hydration states, interstratifications, and superstructures in the initial vermiculite in China. The water loss in these long and short UV irradiated samples for 168 hours was 4 and 4.5% for the Sta. Olalla sample, 0.9 and 1% for the Chinese sample, and 6.4 and 7% for the Libby sample. In the exfoliation flake samples, an increase in the intensity of the most characteristic reflection is observed, in addition to a larger crystallite size and a lower percentage of deformation, so that the crystallinity increased.

### *2.2.4 Chemical treatment*

*Clay Science and Technology*

and/or Na+

*2.2.2 Pressure treatment*

Under vacuum, P = 1.4⋅10<sup>−</sup><sup>2</sup>

forms to phase 1-WLHS.

*2.2.3 Irradiation treatment*

*2.2.3.1 Microwave irradiation*

and a count time 1 s per step.

*2.2.3.2 Ultraviolet irradiation*

or K+

diffractometer, the last phase did not appear, and it was observed that the structure practically collapsed at 100°C, phase 1-WLHS reappearing as temperature increases. With gradual increase in T in situ, dehydration of the vermiculites could be observed until practically reaching collapse, although the behavior was different

1-WLHS, and dehydroxylation begins at lower temperatures and is faster than in the latter, in which already dehydrated vermiculite coexists with a similar structure to mica.

were carried out on both powder samples and exfoliation flakes of three vermiculites from Sta. Olalla (Huelva, Spain), Paulistana (Piauí, Brazil), and Western China [9]. A Seifert XRD 3000 diffractometer from the Scientific-Technical Services of the University of Oviedo was used. The conditions of use were 30 mA and 40 kV (Cu-Kα radiation, λ = 1.5418 Å), range 2θ between 2 and 70°2θ, speed 0.02°2θ/20 s. Two commercial Leybold pumps (Trivac D 2.5 E (up to 10–2 mbar) and Turbovac TMP

The effect of vacuum, like that of temperature, causes dehydration of vermiculite but with a different evolution through the different states of hydration. In fact, under vacuum, the process appears to inhibit itself to a state of hydration with one layer of water (1-WLHS). The role of T is inhibited against that of pressure. The Sta. Olalla vermiculite gave rise to the formation of three different interstratified phases: two phases characterized by an interstratification with interplanar distances, *d* = 11.5–13.8 Å and *d* = 9.6–11.5 Å, respectively, and another phase with *d* = 13.8 Å.

was observed with two layers of water coexisting with phase 2-WLHS but with a layer of water. In Piauí vermiculite, the evolution of the most characteristic reflection was more remarkable since it disappears, appearing in phase 1-WLHS.

The effect was faster with powder samples, and phase 2-WLHS quickly trans-

The transformations undergone by the vermiculites subjected to microwave irradiation (at 800 W and exposure times from 10 to 20 s) were characterized by X-ray diffraction [24]. A PHILIPS X'PERT PRO X-ray diffractometer was used, at 40 mA and 45 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–70°2θ, steps of 0.02°,

Microwave irradiation of vermiculite samples caused much less water loss than they do when subjected to sudden high-temperature heating; it also caused exfoliation of the material. From a structural point of view, the X-ray diffraction patterns of the vermiculites of Sta. Olalla, China, and Libby showed loss of crystallinity and disorder.

The changes induced by ultraviolet (UV), short wave (254 nm), and long (356 nm) radiation at different times (1 hour, 1 day, and 1 week) in vermiculites from Sta. Olalla, Libby, and China were studied by using X-ray diffraction [46]. A PHILIPS X'PERT PRO X-ray diffractometer was used, at 40 mA and 45 kV,

mbar, in the Sta. Olalla, vermiculite phase 2-WLHS

and/or Ca2+. In the former dehydration appears to be restricted to

in the interlayer

mbar

mbar and P = 2.4⋅10<sup>−</sup><sup>4</sup>

depending on whether the samples contained Mg2+ or Mg2+ and K+

The experiments at atmospheric pressure P = 1.4⋅10<sup>−</sup><sup>2</sup>

50 (up to 10–4 mbar)) were used for the vacuum experiments.

**38**

By **ion exchange of metals** (Ni2+, Fe2+, Fe3+) for the Mg2+ of the interlayer in the vermiculite-Mg of Sta. Olalla (Huelva, Spain).

In the case of nickel [35], an aqueous solution of Ni2+ acetate was used, and in the case of iron [47], FeCl2 and FeCl3 solutions were used. The crystal structures of the nickel and iron vermiculites were refined using the DIFFaX+ program [48] (and a later version). The characterization was carried out with X-ray diffraction by transmission using an InEL XRD RG3000 cobalt tube vertical diffractometer (λ = 1.7890 Å) (40 kV, 35 mA) and an InEL CPS 120 detector, in the 2θ range of 4–70° (step 0.03°, total acquisition time of 5400 s). Refinement confirmed the similarity of the Ni2+-, Fe2+-, and Fe3+-vermiculites with the Mg-vermiculite. In the Fe2+-vermiculite reflections corresponding to the akaganeite (β-FeOOH) (JCPDS card 01–075-1594), a phase that was corroborated by Mössbauer spectroscopy (16%) was observed, a technique that also allowed showing the presence of said phase (3%) in the Fe3+-vermiculite. Only vermiculite was detected in the Ni2+ vermiculites obtained from the starting vermiculite, while in the one obtained from the homoionized starting vermiculite (with brucite -Mg (OH)2<sup>−</sup>), a brucite phase with magnesium and nickel was also detected. In this refinement it was found that Ni2+ and Fe2+ also enter the octahedral layer, although there was no evidence for Fe3+.

### *2.2.4.1 Acid activation with HNO3*

Nitric acid treatment at 4 and 8 M was used at room temperature and different treatment times on the purest vermiculite from Sta. Olalla and two commercial vermiculites from Goiás and China, respectively [49]. To quantify potential loss of mass or water, 1 mL of each sample was weighed pre- and post-acidic treatment, and their volume post-treatment was measured. To identify any structural change, X-ray diffraction patterns were taken with a PANalytical X'pertPro diffractometer using 40 mA and 45 kV (Cu-Kα radiation; λ = 1.5418 Å), 2θ scans 5–35o, 2θ step scans of 0.007°, and a counting time of 1 s per step. TEM high-resolution microscope with a resolution of 1.9 Å between points and 1.0 Å between lines was used to obtain TEM and selected area electron diffraction (SAED) micrographs with its accompanied CCD camera (Gatan).

Vermiculites treated with acid suffered (a) slight delamination and color (**Figure 6**); (b) weight loss (**Table 3**) due to the mass and water loss; (c) inhomogeneous cation leaching, probably achieved to transfer iron from those octahedral sheets to clusters deposited on vermiculite layers (**Figure 7**) [50–53] (and in the samples with

### **Figure 6.**

*Color of treated vermiculite from Sta. Olalla.*


### **Table 3.**

*Weight loss (%) in the treated samples.*

high iron content, this element would have prevented further leaching of cations but not water loss); and (d) structural transformation that resulted in the formation of lamellar products with low crystallinity and order, composed by amorphous silica and other phases whose identity and percentage varied depending on the vermiculite type.

### *2.2.5 Thermal and chemical treatment*

### *2.2.5.1 Thermal treatment and subsequent reaction with metal ions solution (Cr3+ y Ni2+)*

For the experiments with Cr3+ [54] and Cr6+ [55], commercial vermiculite from China thermo-exfoliated at 900°C for 1 minute was used. With Ni2+, commercial from Piauí (Brazil) and China, vermiculites thermo-exfoliated at 1000°C for 1 minute were used [35].

**41**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

Vermiculite characterization after Cr3+ adsorption was performed with X-ray diffraction using a Bruker AXS D8 Advance diffractometer with an Anton Paar HTK1200 oven at room temperature and 900°C for 1 minute. The equipment conditions were 30 mA and 40 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–40°2θ, 0.1°

The X-ray spectra of Chinese vermiculite after having been in contact with a solution of synthetic seawater and dissolved Cr3+ with concentrations of 0.75 and 2.0 ppm suggested that the mica-like phase of the exfoliated vermiculite would have been transformed back into a vermiculite-like structure, similar to that of the original sample. In contrast, in the X-ray spectrum of Chinese vermiculite after having been in contact with distilled water solution and dissolved Cr6+ with concentrations

Several experiments with vermiculite samples from Sta. Olalla (Huelva, Spain), Libby (Montana, USA), and Goiás (Brazil), in both powder and flakes forms, were carried out [56]: (a) treatment with 30% and 50% hydrogen peroxide solution, at different times for each sample; (b) irradiation with microwaves for 20 s of Libby and Goiás samples; and (c) treatment with 30% and 50% hydrogen peroxide solution in the microwave oven for 20 s of vermiculite samples from Goiás. X-ray diffraction was used to identify structural changes. For the powder samples, a PHILIPS X'PERT PRO diffractometer was used at 40 mA and 45 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–70°2θ, steps of 0.02°, and a count time 1 s per step. For the flake samples, a Seifert XDR 3000 T/T diffractometer was used at 30 mA and 40 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 2–10°2θ, steps of 0.02°, and a time of 20 s count per step. The results showed that the vermiculites hardly underwent changes at the structure level, despite the change in appearance and textural (color, exfoliation, corrugation, undulations) (**Figure 6**). The three vermiculites—Sta. Olalla, Goiás, and Libby—showed a slight increase in the intensity of the main reflection. The change was slower in

The structural changes of commercial vermiculites treated with alcohol and alcohol for 1 month and subsequent microwave irradiation for 20 seconds were

powder form than in flake samples, at least in Libby vermiculite. **Alcohol** (methanol, ethanol, propanol, butanol).

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

steps, and a count time of 20 s per step.

*TEM and SAED micrograph of polycrystalline goethite in Goiás vermiculite .*

of 1 ppm (**Figure 8**), no change is observed.

*2.2.5.2 Hydrogen peroxide*

**Figure 7.**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

### **Figure 7.**

*Clay Science and Technology*

**40**

*2.2.5 Thermal and chemical treatment*

*(Cr3+ y Ni2+)*

*Weight loss (%) in the treated samples.*

*Color of treated vermiculite from Sta. Olalla.*

*Marcos et al. [49].*

**Table 3.**

**Figure 6.**

1 minute were used [35].

high iron content, this element would have prevented further leaching of cations but not water loss); and (d) structural transformation that resulted in the formation of lamellar products with low crystallinity and order, composed by amorphous silica and other phases whose identity and percentage varied depending on the vermiculite type.

**Samples HNO3 molarity Time Weight loss (%)** Sta. Olalla 4 1 70

Goiás 4 1 12

China 4 1 22

7 75

7 70

7 14

7 47

7 27

7 52

8 1 72

8 1 47

8 1 53

For the experiments with Cr3+ [54] and Cr6+ [55], commercial vermiculite from China thermo-exfoliated at 900°C for 1 minute was used. With Ni2+, commercial from Piauí (Brazil) and China, vermiculites thermo-exfoliated at 1000°C for

*2.2.5.1 Thermal treatment and subsequent reaction with metal ions solution* 

*TEM and SAED micrograph of polycrystalline goethite in Goiás vermiculite .*

Vermiculite characterization after Cr3+ adsorption was performed with X-ray diffraction using a Bruker AXS D8 Advance diffractometer with an Anton Paar HTK1200 oven at room temperature and 900°C for 1 minute. The equipment conditions were 30 mA and 40 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–40°2θ, 0.1° steps, and a count time of 20 s per step.

The X-ray spectra of Chinese vermiculite after having been in contact with a solution of synthetic seawater and dissolved Cr3+ with concentrations of 0.75 and 2.0 ppm suggested that the mica-like phase of the exfoliated vermiculite would have been transformed back into a vermiculite-like structure, similar to that of the original sample. In contrast, in the X-ray spectrum of Chinese vermiculite after having been in contact with distilled water solution and dissolved Cr6+ with concentrations of 1 ppm (**Figure 8**), no change is observed.

### *2.2.5.2 Hydrogen peroxide*

Several experiments with vermiculite samples from Sta. Olalla (Huelva, Spain), Libby (Montana, USA), and Goiás (Brazil), in both powder and flakes forms, were carried out [56]: (a) treatment with 30% and 50% hydrogen peroxide solution, at different times for each sample; (b) irradiation with microwaves for 20 s of Libby and Goiás samples; and (c) treatment with 30% and 50% hydrogen peroxide solution in the microwave oven for 20 s of vermiculite samples from Goiás. X-ray diffraction was used to identify structural changes. For the powder samples, a PHILIPS X'PERT PRO diffractometer was used at 40 mA and 45 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–70°2θ, steps of 0.02°, and a count time 1 s per step. For the flake samples, a Seifert XDR 3000 T/T diffractometer was used at 30 mA and 40 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 2–10°2θ, steps of 0.02°, and a time of 20 s count per step. The results showed that the vermiculites hardly underwent changes at the structure level, despite the change in appearance and textural (color, exfoliation, corrugation, undulations) (**Figure 6**). The three vermiculites—Sta. Olalla, Goiás, and Libby—showed a slight increase in the intensity of the main reflection. The change was slower in powder form than in flake samples, at least in Libby vermiculite.

**Alcohol** (methanol, ethanol, propanol, butanol).

The structural changes of commercial vermiculites treated with alcohol and alcohol for 1 month and subsequent microwave irradiation for 20 seconds were

**Figure 8.**

*X-ray diffraction of the starting Chinese vermiculite and abruptly heated at 900°C for 1 minute (a) and after having been in contact with 1 ppm Cr6+ in distilled water (b).*

analyzed using X-ray diffraction [57, 58]. The equipment used was a PHILIPS X'PERT PRO diffractometer, at 40 mA and 45 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–12°2θ, steps of 0.007°, and a count time of 1 s per step. Changes in the intensity and position of the basal reflections were used to indicate changes in the structural order and in the hydration states. In Sta. Olalla vermiculite, the intensity of the most characteristic reflection decreased with all the alcohols and times investigated. In the Chinese and Libby vermiculites, the intensity of the most characteristic reflections with methanol and ethanol also decreased, while with propanol and butanol, as a function of time, there was an increase in intensity and optimization of the profile of the aforementioned reflections and incipient appearance of phases with different hydration states (in Chinese vermiculite).

**43**

**3. Discussion**

**Figure 9.**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

The diffraction spectra for the vermiculite particles from China and Libby treated with alcohol for 1 month and subsequent microwave irradiation for 20 seconds, exfoliated and non-exfoliated, are shown in **Figure 9** [59]. In these vermiculites treated with butanol or propanol and subsequent microwave irradiation, it should be noted that the crystallinity and the order of phases 2- and 2-1-WLHS of the exfoliated and non-exfoliated particles improved in relation to the untreated ones, except in Chinese exfoliated particles after butanol treatment and subsequent microwave irradiation. The opposite occurred with methanol or ethanol treatment and subsequent microwave irradiation, except in the Chinese exfoliated particles

*X-ray diffraction of the samples from China (a) and Libby (b) treated with alcohol for 1 month and subsequent microwave irradiation for 20 seconds (Marcos et al. [59]). Note: m = methanol, e = ethanol,* 

The structural modifications of the investigated vermiculites treated thermally,

with vacuum, or irradiation or chemically, consist of the phase transformation

after methanol treatment and subsequent microwave irradiation.

*b = butanol, p = propanol, ex = exfoliated, no = no exfoliated.*

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

### **Figure 9.**

*Clay Science and Technology*

**42**

**Figure 8.**

analyzed using X-ray diffraction [57, 58]. The equipment used was a PHILIPS X'PERT PRO diffractometer, at 40 mA and 45 kV, Cu-Kα radiation (λ = 1.5418 Å), range of 3–12°2θ, steps of 0.007°, and a count time of 1 s per step. Changes in the intensity and position of the basal reflections were used to indicate changes in the structural order and in the hydration states. In Sta. Olalla vermiculite, the intensity of the most characteristic reflection decreased with all the alcohols and times investigated. In the Chinese and Libby vermiculites, the intensity of the most characteristic reflections with methanol and ethanol also decreased, while with propanol and butanol, as a function of time, there was an increase in intensity and optimization of the profile of the aforementioned reflections and incipient appearance of phases

*X-ray diffraction of the starting Chinese vermiculite and abruptly heated at 900°C for 1 minute (a) and after* 

with different hydration states (in Chinese vermiculite).

*having been in contact with 1 ppm Cr6+ in distilled water (b).*

*X-ray diffraction of the samples from China (a) and Libby (b) treated with alcohol for 1 month and subsequent microwave irradiation for 20 seconds (Marcos et al. [59]). Note: m = methanol, e = ethanol, b = butanol, p = propanol, ex = exfoliated, no = no exfoliated.*

The diffraction spectra for the vermiculite particles from China and Libby treated with alcohol for 1 month and subsequent microwave irradiation for 20 seconds, exfoliated and non-exfoliated, are shown in **Figure 9** [59]. In these vermiculites treated with butanol or propanol and subsequent microwave irradiation, it should be noted that the crystallinity and the order of phases 2- and 2-1-WLHS of the exfoliated and non-exfoliated particles improved in relation to the untreated ones, except in Chinese exfoliated particles after butanol treatment and subsequent microwave irradiation. The opposite occurred with methanol or ethanol treatment and subsequent microwave irradiation, except in the Chinese exfoliated particles after methanol treatment and subsequent microwave irradiation.

### **3. Discussion**

The structural modifications of the investigated vermiculites treated thermally, with vacuum, or irradiation or chemically, consist of the phase transformation

and the increase or loss of crystallinity and, therefore, the increase or decrease of the structural order. Depending on the treatment, the increase in crystallinity may be accompanied by the appearance of the majority starting phase, and the loss of crystallinity may be accompanied by the appearance or disappearance of interstratified phases.

Vermiculite responds to an increase of T by transforming its structure, which affects its applications. It is a dynamic process that depends on the composition, size, and shape of the particle, relative humidity, and process conditions (in situ or ex situ heating). With T increase, the transformations occur due to dehydration, greater in the purest vermiculites and less in the most micaceous ones. With abrupt ex situ heating, at 1000°C, with powder samples, the purest vermiculites are transformed into enstatite and the least pure into mica and enstatite; in both cases they appear expanded and exfoliated. With gradual heating in situ, at 1000°C and in flake samples, the structure practically collapses in the purest and the most micaceous vermiculites; although it fails to do so, its crystallinity is very low. Dehydration would occur by the escape of water in the form of steam. This escape would occur when the vapor pressure exceeds the bonding forces that hold the layers together, causing exfoliation and expansion [15]. The process occurs faster in powder samples than in flake samples.

The effect of the vacuum is similar to that of the temperature increase; the transformation also occurs by dehydration, although the process seems to be inhibited to a state of hydration with a layer of water (1-WLHS), without additional dehydration of the samples up to a state of hydration of zero layers of water (0-WLHS). The loss of water was less than with an increase in T. The process is slower than with an increase in temperature in situ since the pressure does not imply an increase in the activation energy as with the first. In addition, it was shown that the dehydration process occurs through different interstratified states in vermiculite. This result has been related to the content of Mg2+ cations in the interlayer, due to its affinity with water molecules. The purest vermiculite of Sta. Olalla showed the most complex dehydration process due to its higher magnesium content in the interlayer. Due to its affinity for water, the higher the content of the cation, the greater the difficulty in eliminating water molecules. When the temperature and the vacuum are acting simultaneously, the sample is dehydrated just after the vacuum is established, and the temperature has no additional effect. The process, as with temperature increase, occurs more quickly in powder samples than in sheet samples.

Microwave irradiation of vermiculite samples caused a loss of water much lower than what they suffer when subjected to sudden heating at high temperature. The said dehydration was slower than with vacuum or with sudden heating at 1000°C. As a consequence, the phase with *d* = 13.8 Å in Sta. Olalla, for example, could not be observed. The crystallinity loss and structural disorder is attributable to the water loss. There was no collapse of the structure or formation of new phases, probably because this loss was much lower than that produced at a temperature higher than that produced by microwave radiation. The expansion process began in the flake center and advanced toward the edges. The alignment and reorientation of the water dipoles with the applied field generated internal friction that caused the heating of the vermiculite and the vaporization of many of the water molecules. The explanation of steam escape and exfoliation would be the same as when the temperature rises.

The decrease in crystallinity and structural order in vermiculite powder samples irradiated with long and short UV is also attributable to the water loss. On the contrary, in crystalline samples the crystallinity and structural order increased. In this case there was surely rehydration by ambient humidity adsorption.

**45**

to 900°C.

interlayer which has Na+

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

In the chemical treatment by ion exchange of Ni2+ or Fe2+ or Fe3+ metals by the Mg2+ of the interlayer in the Mg- vermiculite of Sta. Olalla, the decrease in the interplanar distance *d*002 has been interpreted as due to the interaction of the cation and a possible modification of the interactions between the exchanged cation and the TOT sheets, due to both the nature of the new cation and the variations in the quantity and distribution of the H2O molecules that it induces. The formation of brucite in the homoionized starting vermiculite could be due to the homoionization process itself, consisting of introducing the vermiculite in a solution of MgCl2 in

In the vermiculite intercalated with nickel from this homoionized vermiculite, a

first caused the replacement of the exchangeable cations (Mg2+, Ca2+, K+

According to Ravichandran and Sivasankar [50], the reaction with nitric acid

protons, which will subsequently attacked the layers. Secondly, partial leaching of Al2+, Mg2+, and Fe2+ and Fe3+ from the tetrahedral and octahedral layers occurred. The silicon remained in the form of amorphous silica and quartz; this lasts in a very low percentage, which disappeared with the increase of the acid concentration in any of the samples. The Sta. Olalla sample suffered greater leaching of cations and water loss than the Goiás and China samples, whose high iron content would have

The heat treatment of the vermiculites and subsequent reaction with synthetic seawater solutions with Cr3+ and Ni2+ would have caused the reappearance of the starting vermiculite, by rehydration. Probably, its union with the water trapped in the thermo-exfoliated structure may have made this structure closer to the original, that is, the mica-like structure would have moved back to that of the vermiculite. In aqueous solution Cr3+ would be in the form [Cr(H2O)6] 3+ and Ni2+ as [Ni(H2O)6]

both cases its adsorption in thermally expanded vermiculites would be controlled by different cooperative mechanisms: (1) cation exchange and (2) surface complexation reactions [60–63]. It is important to note that a very low percentage of Ni2+ could have precipitated in the pores or on the surface of vermiculite such as magnesium and nickel hydroxide, according to the findings in unheated Ni2+-, Fe2+-, and Fe3+ vermiculites [35, 47]. The cation exchange process would be favored by the fact that Cr3+ and Ni2+ have an ionic radius (0.69 and 0.78 Å, respectively), similar to that of Mg2+ (0.72 Å). This ion exchange process would have taken place considering that the product resulting from the heating of vermiculite would constitute a heterogeneous system formed by one or more disordered crystalline phases (mica type) with hydroxyl groups and some cations between layers of the original phase and molecules of water. This transformation would have occurred due to the rehydration of the sample in the adsorption process, which should be directly related to the characteristics of the cation involved [64]. The transformation in both cases would be consistent with the investigations carried out by Derkowski and McCarty [65] on the rehydration of dehydroxylated smectite in an environment of low water vapor. The equilibrium occurs in the solid/liquid interface, where the available centers located on the surface could be exchanged with the species in the solution. This adsorption process would be the opposite of what happens to vermiculite when it expands

The transformation could have occurred due to two aspects: on the one hand,

mation because there was no hydration or dehydration, since there was no change in weight before and after the adsorption of the ion by expanded vermiculite, probably

in relation to Mg2+ or Ca2+ [66]. In the case of no transfor-

solution and on the other hand the lower force of attraction with the water of the

the ionic exchange of ions of the interlayer with Na+

due to the characteristics of the cation involved [64].

, Ca2+, etc., coexisting with Mg2+.

and other ions of the saline

, Na+

) by

2+; in

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

order to eliminate possible impurities such as Na+

prevented further leaching of other cations.

brucitic phase with magnesium and nickel was also detected.

### *Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

In the chemical treatment by ion exchange of Ni2+ or Fe2+ or Fe3+ metals by the Mg2+ of the interlayer in the Mg- vermiculite of Sta. Olalla, the decrease in the interplanar distance *d*002 has been interpreted as due to the interaction of the cation and a possible modification of the interactions between the exchanged cation and the TOT sheets, due to both the nature of the new cation and the variations in the quantity and distribution of the H2O molecules that it induces. The formation of brucite in the homoionized starting vermiculite could be due to the homoionization process itself, consisting of introducing the vermiculite in a solution of MgCl2 in order to eliminate possible impurities such as Na+ , Ca2+, etc., coexisting with Mg2+. In the vermiculite intercalated with nickel from this homoionized vermiculite, a brucitic phase with magnesium and nickel was also detected.

According to Ravichandran and Sivasankar [50], the reaction with nitric acid first caused the replacement of the exchangeable cations (Mg2+, Ca2+, K+ , Na+ ) by protons, which will subsequently attacked the layers. Secondly, partial leaching of Al2+, Mg2+, and Fe2+ and Fe3+ from the tetrahedral and octahedral layers occurred. The silicon remained in the form of amorphous silica and quartz; this lasts in a very low percentage, which disappeared with the increase of the acid concentration in any of the samples. The Sta. Olalla sample suffered greater leaching of cations and water loss than the Goiás and China samples, whose high iron content would have prevented further leaching of other cations.

The heat treatment of the vermiculites and subsequent reaction with synthetic seawater solutions with Cr3+ and Ni2+ would have caused the reappearance of the starting vermiculite, by rehydration. Probably, its union with the water trapped in the thermo-exfoliated structure may have made this structure closer to the original, that is, the mica-like structure would have moved back to that of the vermiculite. In aqueous solution Cr3+ would be in the form [Cr(H2O)6] 3+ and Ni2+ as [Ni(H2O)6] 2+; in both cases its adsorption in thermally expanded vermiculites would be controlled by different cooperative mechanisms: (1) cation exchange and (2) surface complexation reactions [60–63]. It is important to note that a very low percentage of Ni2+ could have precipitated in the pores or on the surface of vermiculite such as magnesium and nickel hydroxide, according to the findings in unheated Ni2+-, Fe2+-, and Fe3+ vermiculites [35, 47]. The cation exchange process would be favored by the fact that Cr3+ and Ni2+ have an ionic radius (0.69 and 0.78 Å, respectively), similar to that of Mg2+ (0.72 Å). This ion exchange process would have taken place considering that the product resulting from the heating of vermiculite would constitute a heterogeneous system formed by one or more disordered crystalline phases (mica type) with hydroxyl groups and some cations between layers of the original phase and molecules of water.

This transformation would have occurred due to the rehydration of the sample in the adsorption process, which should be directly related to the characteristics of the cation involved [64]. The transformation in both cases would be consistent with the investigations carried out by Derkowski and McCarty [65] on the rehydration of dehydroxylated smectite in an environment of low water vapor. The equilibrium occurs in the solid/liquid interface, where the available centers located on the surface could be exchanged with the species in the solution. This adsorption process would be the opposite of what happens to vermiculite when it expands to 900°C.

The transformation could have occurred due to two aspects: on the one hand, the ionic exchange of ions of the interlayer with Na+ and other ions of the saline solution and on the other hand the lower force of attraction with the water of the interlayer which has Na+ in relation to Mg2+ or Ca2+ [66]. In the case of no transformation because there was no hydration or dehydration, since there was no change in weight before and after the adsorption of the ion by expanded vermiculite, probably due to the characteristics of the cation involved [64].

*Clay Science and Technology*

powder samples than in flake samples.

fied phases.

and the increase or loss of crystallinity and, therefore, the increase or decrease of the structural order. Depending on the treatment, the increase in crystallinity may be accompanied by the appearance of the majority starting phase, and the loss of crystallinity may be accompanied by the appearance or disappearance of interstrati-

Vermiculite responds to an increase of T by transforming its structure, which affects its applications. It is a dynamic process that depends on the composition, size, and shape of the particle, relative humidity, and process conditions (in situ or ex situ heating). With T increase, the transformations occur due to dehydration, greater in the purest vermiculites and less in the most micaceous ones. With abrupt ex situ heating, at 1000°C, with powder samples, the purest vermiculites are transformed into enstatite and the least pure into mica and enstatite; in both cases they appear expanded and exfoliated. With gradual heating in situ, at 1000°C and in flake samples, the structure practically collapses in the purest and the most micaceous vermiculites; although it fails to do so, its crystallinity is very low. Dehydration would occur by the escape of water in the form of steam. This escape would occur when the vapor pressure exceeds the bonding forces that hold the layers together, causing exfoliation and expansion [15]. The process occurs faster in

The effect of the vacuum is similar to that of the temperature increase; the transformation also occurs by dehydration, although the process seems to be inhibited to a state of hydration with a layer of water (1-WLHS), without additional dehydration of the samples up to a state of hydration of zero layers of water (0-WLHS). The loss of water was less than with an increase in T. The process is slower than with an increase in temperature in situ since the pressure does not imply an increase in the activation energy as with the first. In addition, it was shown that the dehydration process occurs through different interstratified states in vermiculite. This result has been related to the content of Mg2+ cations in the interlayer, due to its affinity with water molecules. The purest vermiculite of Sta. Olalla showed the most complex dehydration process due to its higher magnesium content in the interlayer. Due to its affinity for water, the higher the content of the cation, the greater the difficulty in eliminating water molecules. When the temperature and the vacuum are acting simultaneously, the sample is dehydrated just after the vacuum is established, and the temperature has no additional effect. The process, as with temperature increase, occurs more quickly in powder samples than

Microwave irradiation of vermiculite samples caused a loss of water much lower than what they suffer when subjected to sudden heating at high temperature. The said dehydration was slower than with vacuum or with sudden heating at 1000°C. As a consequence, the phase with *d* = 13.8 Å in Sta. Olalla, for example, could not be observed. The crystallinity loss and structural disorder is attributable to the water loss. There was no collapse of the structure or formation of new phases, probably because this loss was much lower than that produced at a temperature higher than that produced by microwave radiation. The expansion process began in the flake center and advanced toward the edges. The alignment and reorientation of the water dipoles with the applied field generated internal friction that caused the heating of the vermiculite and the vaporization of many of the water molecules. The explanation of steam escape and exfoliation would be the same as when the

The decrease in crystallinity and structural order in vermiculite powder samples

irradiated with long and short UV is also attributable to the water loss. On the contrary, in crystalline samples the crystallinity and structural order increased. In

this case there was surely rehydration by ambient humidity adsorption.

**44**

in sheet samples.

temperature rises.

In the case of the adsorption of Ni2+ by vermiculite, the behavior would have been similar to that of the adsorption of Cr3+ [54], although it would have to be confirmed experimentally.

The reaction with hydrogen peroxide showed textural rather than structural changes. The water content (**Table 4**) was practically the same in both the Goiás and Libby samples treated with H2O2 and untreated. The absence of hydrationdehydration is the cause of no phase transformation.

The leached cations, in greater quantity those of the interlayer (Na<sup>+</sup> , K+ , etc.) than those of the tetrahedral and octahedral layers, would be replaced by the H+ ions of the solution [21]. These ions gave rise to two effects: (1) increase of the pH of the solution and (2) corrosion of the vermiculite particles.

The structural changes of commercial vermiculites treated with alcohol, dehydration-hydration, and disorder-order would be related to the replacement of water by alcohol in a very low percentage, with weight loss and, depending on the type of vermiculite, appearance of phases with state of hydration of less layers of water. The structural changes of commercial vermiculites treated with alcohol and subsequent irradiation with microwaves consist of an increase or decrease in crystallinity and order. The results indicated dehydration-hydration and structural order-disorder that would be related to the entry of alcohol into vermiculites by water replacement, that is, by loss of water. The changes occurred in a manner similar to those produced with temperature and vacuum and were less pronounced for the purest vermiculite.

Structural changes of vermiculites induced by the above mentioned treatments provide evaluable information on the relationship between the structure of vermiculite and their industrial applications. In vermiculite applications as intumescent fire barriers [67–69] where exfoliation at low temperatures is required, the treatment type, in this case microwave irradiation, is more important than the structural change suffered by vermiculite. In the case of vacuum, not only the type of treatment but also the structural changes suffered by the vermiculite influence, since under pressure the vermiculite could act as a deposit mineral and host contaminating elements. Vermiculite irradiated with ultraviolet radiation could be used as material for optoelectronic devices because this radiation is less penetrating and easier and cheaper to obtain than gamma radiation [70]. Fe2+- and Fe3+ vermiculites maintain its paramagnetic character; and Ni2+- vermiculite behaves as a two-dimensional spin-glass system in which planar ferro- and antiferromagnetic interactions compete, responsible for the complex magnetic behavior found. Ni2+- vermiculites are interesting materials to study experimentally or


*b Samples treated with alcohol and irradiated simultaneously with microwaves.*

### **Table 4.**

*Water content (%) obtained by thermogravimetry of untreated and treated samples of Sta. Olalla, Goiás, and Libby.*

**47**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

in simulations, with applications to physics, chemistry, materials science, and artificial neural networks in computing [71]. Alcohol treatment and subsequent microwave irradiation may be the procedure for obtaining purest vermiculite from a less pure sample. Nitric acid treatment of vermiculites with high iron content resulted in a lamellar products with high porosity, important in many applications such as low cost and efficient and sustainable adsorbent for dyes and metals [60, 72–74]. It is important to highlight how exfoliated vermiculites can remain unchanged depending on the valence of the adsorbed ion and the salinity and pH

Consequently, the relationship between structural changes of vermiculite and the chemical and physical treatments could contribute to predicting the structural order–disorder of the vermiculite; the obtaining of purest vermiculite; the environmental fate of toxic metals, such as cesium (radioactive metal) in contaminated areas; and developing methods to extract these metals from contaminated soils or

Further, the changes suffered by vermiculites due to the treatments applied could give light to ambiguities about their geological origin due to hydrothermal and/or supergene processes. However, most and possibly all macroscopic vermiculite and interstratifications of vermiculite and other phases (mica, chlorite) are believed to be of supergene origin [76, 77]. The changes suffered by vermiculites due to hydrogen peroxide treatment and ionic metal exchange, with water gain, could point to this origin, corroborating both the field and laboratory evidence in early times [76]. Regarding the treatments that involve water loss in vermiculites, it is not discarded that a more detailed study helps to reveal data related to the hydrothermal origin. Some aspects observed in the transformations caused by treatments

content in the interlayer have more inter-

with water loss could coincide with field observations [78, 79].

stratified phases and lower water content and are less crystalline.

vermiculite, or the environmental fate of toxic metals.

The crystallinity loss and therefore the structural disorder increase are caused by the structural water loss. On the contrary, the crystallinity increase is produced by

The vermiculite transformation by structural water loss occurs with temperature increasing, vacuum, irradiation with microwaves or ultraviolet, and both alcohol and acidic treatment. On the contrary, the transformation by water gain occurs in vermiculites treated with hydrogen peroxide and in those subjected to ionic metal

Structural changes of vermiculites induced by the abovementioned treatments provide evaluable information on the relationship between the structure of vermiculite and their industrial applications. The said relationship would allow predicting the structural order-disorder of the vermiculite, the obtaining of purest

The changes suffered by vermiculites due to the treatments applied could give light to ambiguities about their geological origin and hydrothermal and/or supergene processes. Early field and laboratory evidence and current experiments showing changes in vermiculites caused by treatment with hydrogen peroxide and ion-metal exchange, with water gain, could point to a supergenic origin. Regarding the treatments that involve water loss in vermiculites, it is not discarded that a more

detailed study helps to reveal data related to the hydrothermal origin.

*DOI: http://dx.doi.org/10.5772/intechopen.92436*

of the medium.

waters [75].

**4. Conclusions**

water gain.

exchange.

Starting vermiculites with high K<sup>+</sup>

### *Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation… DOI: http://dx.doi.org/10.5772/intechopen.92436*

in simulations, with applications to physics, chemistry, materials science, and artificial neural networks in computing [71]. Alcohol treatment and subsequent microwave irradiation may be the procedure for obtaining purest vermiculite from a less pure sample. Nitric acid treatment of vermiculites with high iron content resulted in a lamellar products with high porosity, important in many applications such as low cost and efficient and sustainable adsorbent for dyes and metals [60, 72–74]. It is important to highlight how exfoliated vermiculites can remain unchanged depending on the valence of the adsorbed ion and the salinity and pH of the medium.

Consequently, the relationship between structural changes of vermiculite and the chemical and physical treatments could contribute to predicting the structural order–disorder of the vermiculite; the obtaining of purest vermiculite; the environmental fate of toxic metals, such as cesium (radioactive metal) in contaminated areas; and developing methods to extract these metals from contaminated soils or waters [75].

Further, the changes suffered by vermiculites due to the treatments applied could give light to ambiguities about their geological origin due to hydrothermal and/or supergene processes. However, most and possibly all macroscopic vermiculite and interstratifications of vermiculite and other phases (mica, chlorite) are believed to be of supergene origin [76, 77]. The changes suffered by vermiculites due to hydrogen peroxide treatment and ionic metal exchange, with water gain, could point to this origin, corroborating both the field and laboratory evidence in early times [76]. Regarding the treatments that involve water loss in vermiculites, it is not discarded that a more detailed study helps to reveal data related to the hydrothermal origin. Some aspects observed in the transformations caused by treatments with water loss could coincide with field observations [78, 79].

### **4. Conclusions**

*Clay Science and Technology*

confirmed experimentally.

for the purest vermiculite.

dehydration is the cause of no phase transformation.

of the solution and (2) corrosion of the vermiculite particles.

**Samples Treatment — Microwave** 

**irradiation**

Libby 10.3 11.1 3.4 10.9 11.4

*Water content (%) obtained by thermogravimetry of untreated and treated samples of Sta. Olalla, Goiás,* 

Goiás 12.1 12.2 5.6 12.1

*Samples treated with alcohol and irradiated simultaneously with microwaves.*

**1000°C H2O2**

12.7<sup>b</sup>

Sta. Olalla 25.6 24.9 4.9a H2O wt (%)

**30% 50%**

12.1 12.9b

In the case of the adsorption of Ni2+ by vermiculite, the behavior would have been similar to that of the adsorption of Cr3+ [54], although it would have to be

The reaction with hydrogen peroxide showed textural rather than structural changes. The water content (**Table 4**) was practically the same in both the Goiás and Libby samples treated with H2O2 and untreated. The absence of hydration-

, K+

, etc.)

The leached cations, in greater quantity those of the interlayer (Na<sup>+</sup>

than those of the tetrahedral and octahedral layers, would be replaced by the H+ ions of the solution [21]. These ions gave rise to two effects: (1) increase of the pH

The structural changes of commercial vermiculites treated with alcohol, dehydration-hydration, and disorder-order would be related to the replacement of water by alcohol in a very low percentage, with weight loss and, depending on the type of vermiculite, appearance of phases with state of hydration of less layers of water. The structural changes of commercial vermiculites treated with alcohol and subsequent irradiation with microwaves consist of an increase or decrease in crystallinity and order. The results indicated dehydration-hydration and structural order-disorder that would be related to the entry of alcohol into vermiculites by water replacement, that is, by loss of water. The changes occurred in a manner similar to those produced with temperature and vacuum and were less pronounced

Structural changes of vermiculites induced by the above mentioned treatments provide evaluable information on the relationship between the structure of vermiculite and their industrial applications. In vermiculite applications as intumescent fire barriers [67–69] where exfoliation at low temperatures is required, the treatment type, in this case microwave irradiation, is more important than the structural change suffered by vermiculite. In the case of vacuum, not only the type of treatment but also the structural changes suffered by the vermiculite influence, since under pressure the vermiculite could act as a deposit mineral and host contaminating elements. Vermiculite irradiated with ultraviolet radiation could be used as material for optoelectronic devices because this radiation is less penetrating and easier and cheaper to obtain than gamma radiation [70]. Fe2+- and Fe3+ vermiculites maintain its paramagnetic character; and Ni2+- vermiculite behaves as a two-dimensional spin-glass system in which planar ferro- and antiferromagnetic interactions compete, responsible for the complex magnetic behavior found. Ni2+- vermiculites are interesting materials to study experimentally or

**46**

*a*

*b*

**Table 4.**

*and Libby.*

*Marcos et al. [10].*

Starting vermiculites with high K<sup>+</sup> content in the interlayer have more interstratified phases and lower water content and are less crystalline.

The crystallinity loss and therefore the structural disorder increase are caused by the structural water loss. On the contrary, the crystallinity increase is produced by water gain.

The vermiculite transformation by structural water loss occurs with temperature increasing, vacuum, irradiation with microwaves or ultraviolet, and both alcohol and acidic treatment. On the contrary, the transformation by water gain occurs in vermiculites treated with hydrogen peroxide and in those subjected to ionic metal exchange.

Structural changes of vermiculites induced by the abovementioned treatments provide evaluable information on the relationship between the structure of vermiculite and their industrial applications. The said relationship would allow predicting the structural order-disorder of the vermiculite, the obtaining of purest vermiculite, or the environmental fate of toxic metals.

The changes suffered by vermiculites due to the treatments applied could give light to ambiguities about their geological origin and hydrothermal and/or supergene processes. Early field and laboratory evidence and current experiments showing changes in vermiculites caused by treatment with hydrogen peroxide and ion-metal exchange, with water gain, could point to a supergenic origin. Regarding the treatments that involve water loss in vermiculites, it is not discarded that a more detailed study helps to reveal data related to the hydrothermal origin.

### **Conflict of interest**

The author declares that she has no known competing financial interests or personal relationships that could have appeared to influence the work reported in this chapter.

### **Author details**

Celia Marcos Geology Department, Oviedo University, Oviedo, Spain

\*Address all correspondence to: cmarcos@uniovi.es

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**49**

*Structural Changes in Vermiculites Induced by Temperature, Pressure, Irradiation…*

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**Conflict of interest**

this chapter.

The author declares that she has no known competing financial interests or personal relationships that could have appeared to influence the work reported in

**48**

**Author details**

Geology Department, Oviedo University, Oviedo, Spain

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: cmarcos@uniovi.es

provided the original work is properly cited.

Celia Marcos

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[51] Wypych F, Adad LB, Mattoso N, Marangon AAS, Schreiner WH. Synthesis and characterization of disordered layered silica obtained by selective leaching of octahedral sheets from chrysotile and phlogopite structures. Journal of Colloid and Interface Science. 2005;**283**:107-112. DOI: 10.1016/j.jcis.2004.08.139

Clay Science. 2017;**114**:104-114. DOI:

[59] Marcos C, Adawy A, Río del Z;

Chmielarz L, Węgrzyn A, Komędera K, Mordarski G, et al. The influence of acid treatments over vermiculite based material as adsorbent for cationic textile dyestuffs. Chemosphere. 2016;**153**:115-129. DOI: 10.1016/j. chemosphere.2016.03.004

[61] Mercier L, Detellier C. Preparation, characterization, and applications as heavy metals sorbents of covalently

adsorption on montmorillonite. Journal of Colloid and Interface Science.

10.1016/j.clay.2017.05.014

[60] Stawiński W, Freitas O,

grafted thiol functionalities on the interlamellar surface of montmorillonite. Environmental Science and Technology. 1995;**29**:1318

[62] Kraepiel AML, Keller K, Morel FMM. A model for metal

[63] Malandrino M, Abollino O, Giacomino A, Aceto M, Mentasti E. Adsorption of heavy metals on vermiculite: Influence of pH and organic ligands. Journal of Colloid and Interface Science. 2006;**299**:537-546. DOI: 10.1016/j.jcis.2006.03.011

[64] da Fonseca MG, de Oliveira MM, Arakaki LNH, Espinola JGP, Airoldi C. Natural vermiculite as an exchanger support for heavy cations in aqueous solution. Journal of Colloid and

Interface Science. 2005;**285**:50-55. DOI:

10.1016/j.jcis.2004.11.031

[65] Derkowski A, Drits VA, McCarty DK. Rehydration of dehydrated-dehydroxilated smectite in a low water vapor environment. American Mineralogist. 2012;**97**: 110-127. DOI: 10.2138/am.2012.3872

1999;**210**:43-54

Unpublished

[52] Komadel P, Madejova J. Acid activation of clay minerals. In:

Bergaya F, Lagaly G, editors. Handbook of Clay Science (Developments in Clay Science). Vol. 5. 2013. pp. 385-409. DOI: 10.1016/B978-0-08-098258-800.013-4

[53] Chmielarz L, Wojciechowska M, Rutkowska M, Adamski A, Węgrzyn A, Kowalczyk A, et al. Acid activated vermiculites as catalysts of the DeNOx process. Catalysis Today. 2012;**191**:25-31. DOI: 10.1016/j.cattod.2012.03.042

[54] Marcos C, Rodriguez I. Some effects of trivalent chromium exchange of thermo-exfoliated commercial vermiculite. Applied Clay Science. 2014;**90**:96-100. DOI: 10.1016/j.

[55] Marcos C, Medoro V and Adawy A.

[56] Marcos C, Rodriguez I. Exfoliation of vermiculites with chemical treatment using hydrogen peroxide and thermal treatment using microwaves. Applied Clay Science. 2014;**87**:219-227. DOI:

[57] Marcos C, Rodriguez I. Structural changes on vermiculite treated with methanol and ethanol and subsequent microwave irradiation. Applied Clay Science. 2016;**123**:304-314. DOI: 10.1016/j.clay.2016.01.024

[58] Marcos C, Rodriguez I. Effect of propanol and butanol and subsequent microwave irradiation on the structure of commercial vermiculites. Applied

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[69] Zacarias RA, Forte GS, Fontgalland G, Carvalho JN, Idalmir SQ. Thermal analysis of vermiculite using microwave. In: International Instrumentation and Measurement Technology Conference (I2MTC), 14-17 May 2015. Houston, TX, USA: IEEE; 2018. pp. 1-5

[70] Kaur S, Singh S, Singh L. Physiochemical properties of gammairradiated vermiculite and their significance for radiation protection and thermoluminescence. American Mineralogist. 2014;**99**:2018-2024. DOI: 10.2138/am-2014-4873

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[74] Węgrzyn A, Stawiński W, Freitas O, Komędera K, Błachowski A, Jęczmionek Ł, et al. Study of adsorptive materials obtained by wet fine milling and acid activation of vermiculite. Applied Clay Science. 2018;**155**:37-49. DOI: 10.1016/j.clay.2018.01.002

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**Chapter 4**

Adsorption of Heavy Metals

Asphaltite Char/Zeolite

Granule Composts from

Waste Slurries

heavy metal, zeolite composts, shale

**55**

*Yıldırım İsmail Tosun*

**Abstract**

by Microwave Activated Shale/

Hazardous Sludges and Industrial

There is a great concern about surface water pollution with high level mercury, lead (Pb) over 10 mg/l, 30 mg/l to the fishing lakes and streams in Şırnak Province even contaminating fresh water fishing and poisonening of human by merury and lead in thr region. The chromium over 50 mg/l from industrial seepages was disposed to lakes and streams in our country. There is a great green concern prompting land in order to control acidic mine waters so that the research study controlled and avoided hazardous metal limits of residual stream contaminants of heavy metals by sorption local clay and zeolite compost. The contamination rate changes to those based on seepage concentrations and wetness. The stream amendments, such as shale char carbonized from Şırnak asphaltite containing 52–60% shale activated by acid washing under microwave radiation as geo material composted for waste water treatment should control contaminated effluents concentration. The field studies to evaluate the stability of heavy metal concentrations and salts were scarce. The initial objective of this study was to determine the effects of seepage flow to surface and groundwater from the industrial discharge. In this study, important investigations have been made on composite granules production with Şırnak shale char and zeolite feed in order to activated in microwave oven 2 M HCl dissolution. The compost sorbent for high level heavy metal sorption in laboratory water packed bed column adsorption compost system. However, the results of filled packed bed zeolite yield high metal transfer to compost. Due to the complex chemistry of shale pores, and high porosity, heat conduction improved in the microwave sorption depended on granule size decreased. The other heavy metal sorption distribution was changed in the activation dependent on the microwave heating power.

**Keywords:** zeolite, microwave radiation, salt slurries, metal sorption, energy toxic risk assessment, stochastic cost estimation, treatmen sorbent simulation, hybrid sorbent, waste sludge, salt slurries, microwave activation waste water treatment,

### **Chapter 4**

## Adsorption of Heavy Metals by Microwave Activated Shale/ Asphaltite Char/Zeolite Granule Composts from Hazardous Sludges and Industrial Waste Slurries

*Yıldırım İsmail Tosun*

### **Abstract**

There is a great concern about surface water pollution with high level mercury, lead (Pb) over 10 mg/l, 30 mg/l to the fishing lakes and streams in Şırnak Province even contaminating fresh water fishing and poisonening of human by merury and lead in thr region. The chromium over 50 mg/l from industrial seepages was disposed to lakes and streams in our country. There is a great green concern prompting land in order to control acidic mine waters so that the research study controlled and avoided hazardous metal limits of residual stream contaminants of heavy metals by sorption local clay and zeolite compost. The contamination rate changes to those based on seepage concentrations and wetness. The stream amendments, such as shale char carbonized from Şırnak asphaltite containing 52–60% shale activated by acid washing under microwave radiation as geo material composted for waste water treatment should control contaminated effluents concentration. The field studies to evaluate the stability of heavy metal concentrations and salts were scarce. The initial objective of this study was to determine the effects of seepage flow to surface and groundwater from the industrial discharge. In this study, important investigations have been made on composite granules production with Şırnak shale char and zeolite feed in order to activated in microwave oven 2 M HCl dissolution. The compost sorbent for high level heavy metal sorption in laboratory water packed bed column adsorption compost system. However, the results of filled packed bed zeolite yield high metal transfer to compost. Due to the complex chemistry of shale pores, and high porosity, heat conduction improved in the microwave sorption depended on granule size decreased. The other heavy metal sorption distribution was changed in the activation dependent on the microwave heating power.

**Keywords:** zeolite, microwave radiation, salt slurries, metal sorption, energy toxic risk assessment, stochastic cost estimation, treatmen sorbent simulation, hybrid sorbent, waste sludge, salt slurries, microwave activation waste water treatment, heavy metal, zeolite composts, shale

### **1. Introduction**

This investigation of water treatment firstly proposed to control mud in acidic manner even dissolving hazardous coal mine cadmium, lead and mercury can be extremely hazardous in fresh water source contamination even ındustrial waste water management. The contamination research by soil remediation was existing in water logged areas. The strategical problems of water contamination and treatment by different type clay composts and the quality of them mostly exist in the irrigated areas like in South Eastern rocky plains of Şırnak and Batman, Turkey. The climate change and ground water changes generally resulted in over irrigation, seepage losses through channel and distributions, contaminated water control, management practices and inadequate control of drainage system. Analysis of high water table in water logged areas and drainage of irrigated areas have not been paid adequate attention in the planning and management of water resources, partly due to lack of requisite data and partly due to flood and rainfall in the country. In order to develop suitable water management strategies and controlling the extent of water logging in the area. GIS may facilitate the reconstruction of the ecological environment but also to accommodate the sustainable development of the water resources and waste water. In this study, the control of lakes and streams by hydrological characteristics of the Batman city were explained and the effect of soil characteristics on the the city was examined. In the investigation, hydrological features and the urbanization with new settlements need modeling regarding available water source. The hydrological property of settlement areas with dense populated areas in the model was determined by Geographic Information Systems (GIS) techniques. The main purpose of this study is to investigate the effect of settlement on the basic hydrological structure by studying the characteristics of the ground topography, ground water elevation, slope and viewing. GIS techniques were used in the creation of the thematic maps and in the analysis of the parameters. Finally, the GIS study models created, the available water source change and a stream contamination model was provided sufficient source control at the Batman province. The presence of this stream and lake contamination, soil structure in the Batman province reveals the contamination by acidic mine waters and potential flood scale and flood risk. This study produced more hazardous contamination data with hydrological streams dicharged to lakes and streams with GIS. GIS has made it possible to obtain more qualified data by enabling the use of waste water treatment by mobil units in this research (**Figure 1a** and **b**) [1, 2].

The hydrological studies carried out by Water Association showed that high level Tigris river stream flows from 650 m level attitude through 610 m600 m levels laguuns in Batman province with hig risk of flood (**Figure 2**).

The chalky limestone layers of Batman province reveals high amount of water suddenly at the stream below levels to 2 m high over agricultural wheat land and the potential flood risk line [2] (**Figure 3**) [1–3].

rate at higher pH levels over 5 with dissolution of heavy metals in sulphide minerals and neutralization by alkali matters govern the dissolution by the reactions as given

*(a) Satellite view of Batman City and province reveals the potential flood scale 1/20000 and (b) earth view*

*(a) Groundwater Flows and Hydrological Stream Discharges in Batman Province at scale of 1/20000*

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

The sulfide produced is strongly reactive towards heavy metals as given Eqs. (2)

<sup>¼</sup> þ H2O þ 2H<sup>þ</sup> ! H2S þ 3CO2 þ 2H2O (1)

Fe<sup>2</sup><sup>þ</sup> <sup>þ</sup> H2S ! FeS <sup>þ</sup> 2Hþ, (2) Zn2<sup>þ</sup> <sup>þ</sup> H2S ! ZnS <sup>þ</sup> 2Hþ, (3)

Bicarbonate sulphate hot streams reduce aciditiy as below Eq. (1).

below [4–6];

**Figure 2.**

**Figure 1.**

*(b) 1/50000.*

and (3):

**57**

SO4

<sup>¼</sup> þ 2HCO3

*with flood risk water lines of Batman City and province 1/20000.*

### **1.1 Accumulation of contaminating acidic waters, heavy metals and distribution in floods and laguuns near dams**

The oxygen content and and electroopotantial of waters adequately accounted in stream flows causing animal feed contamination n the pastoral fields by soil and growing grass near by this contaminated stream laguuns.

In the hot streams and acidic mine waters the ferric iron and sulfate tend to be highly common as AMD seepage, alkali resulting from the reduction of these two species, a weak base (bicarbonate) and producing astrong base (hydroxyl ions), also generate net alkalinity (Eq. (8)). The indirect acid production was relatively high

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

### **Figure 1.**

**1. Introduction**

*Clay Science and Technology*

research (**Figure 1a** and **b**) [1, 2].

**56**

potential flood risk line [2] (**Figure 3**) [1–3].

**distribution in floods and laguuns near dams**

growing grass near by this contaminated stream laguuns.

This investigation of water treatment firstly proposed to control mud in acidic manner even dissolving hazardous coal mine cadmium, lead and mercury can be extremely hazardous in fresh water source contamination even ındustrial waste water management. The contamination research by soil remediation was existing in water logged areas. The strategical problems of water contamination and treatment by different type clay composts and the quality of them mostly exist in the irrigated areas like in South Eastern rocky plains of Şırnak and Batman, Turkey. The climate change and ground water changes generally resulted in over irrigation, seepage losses through channel and distributions, contaminated water control, management practices and inadequate control of drainage system. Analysis of high water table in water logged areas and drainage of irrigated areas have not been paid adequate attention in the planning and management of water resources, partly due to lack of requisite data and partly due to flood and rainfall in the country. In order to develop suitable water management strategies and controlling the extent of water logging in the area. GIS may facilitate the reconstruction of the ecological environment but also to accommodate the sustainable development of the water resources and waste water. In this study, the control of lakes and streams by hydrological characteristics of the Batman city were explained and the effect of soil characteristics on the the city was examined. In the investigation, hydrological features and the urbanization with new settlements need modeling regarding available water source. The hydrological property of settlement areas with dense populated areas in the model was determined by Geographic Information Systems (GIS) techniques. The main purpose of this study is to investigate the effect of settlement on the basic hydrological structure by studying the characteristics of the ground topography, ground water elevation, slope and viewing. GIS techniques were used in the creation of the thematic maps and in the analysis of the parameters. Finally, the GIS study models created, the available water source change and a stream contamination model was provided sufficient source control at the Batman province. The presence of this stream and lake contamination, soil structure in the Batman province reveals the contamination by acidic mine waters and potential flood scale and flood risk. This study produced more hazardous contamination data with hydrological streams dicharged to lakes and streams with GIS. GIS has made it possible to obtain more qualified data by enabling the use of waste water treatment by mobil units in this

The hydrological studies carried out by Water Association showed that high level Tigris river stream flows from 650 m level attitude through 610 m600 m

The chalky limestone layers of Batman province reveals high amount of water suddenly at the stream below levels to 2 m high over agricultural wheat land and the

The oxygen content and and electroopotantial of waters adequately accounted in stream flows causing animal feed contamination n the pastoral fields by soil and

In the hot streams and acidic mine waters the ferric iron and sulfate tend to be highly common as AMD seepage, alkali resulting from the reduction of these two species, a weak base (bicarbonate) and producing astrong base (hydroxyl ions), also generate net alkalinity (Eq. (8)). The indirect acid production was relatively high

levels laguuns in Batman province with hig risk of flood (**Figure 2**).

**1.1 Accumulation of contaminating acidic waters, heavy metals and**

*(a) Groundwater Flows and Hydrological Stream Discharges in Batman Province at scale of 1/20000 (b) 1/50000.*

### **Figure 2.**

*(a) Satellite view of Batman City and province reveals the potential flood scale 1/20000 and (b) earth view with flood risk water lines of Batman City and province 1/20000.*

rate at higher pH levels over 5 with dissolution of heavy metals in sulphide minerals and neutralization by alkali matters govern the dissolution by the reactions as given below [4–6];

Bicarbonate sulphate hot streams reduce aciditiy as below Eq. (1).

$$\text{\textbullet } \text{SO}\_4^- + 2\text{HCO}\_3^- + \text{H}\_2\text{O} + 2\text{H}^+ \rightarrow \text{H}\_2\text{S} + \text{\textbullet CO}\_2 + 2\text{H}\_2\text{O} \tag{1}$$

The sulfide produced is strongly reactive towards heavy metals as given Eqs. (2) and (3):

$$\text{Fe}^{2+} + \text{H}\_2\text{S} \rightarrow \text{FeS} + 2\text{H}^+,\tag{2}$$

$$\text{Zn}^{2+} + \text{H}\_2\text{S} \rightarrow \text{ZnS} + 2\text{H}^+,\tag{3}$$

**Figure 3.** *Batman province some set reveals the potential flood ban and flood risk.*

which form very insoluble sulfide compounds. FeS is unstable relative to pyrite and the further reaction, which is an oxidation of S2� to S�, as given in Eq. (4);

$$\text{FeS} + \text{S} \rightarrow \text{FeS}\_2 \tag{4}$$

The dissolution kinetics of soil mud particle for Pb heavy metal is followed by

Where cPb Lead contamination mg/l, k the rate of dissolution of lead, i is the

The dissolution concentration of accumulated metal in aliquate of lake streams as regarding Pb heavy metal contamination is followed by equation, where n is

The dissolution concentration of accumulated metal in aliquate of sulfurous hot water streams as regarding Pb heavy metal contamination is followed by equation,

<sup>4</sup> sulphate concentration in effluent. *fi* is concentration rate of sulphate

*tin:dc:fi SO*�<sup>2</sup>

*tin:dc:fi HCO*�<sup>2</sup>

*tin:dc:fi HNO*�<sup>2</sup>

The dissolution rates of heavy metals in acidic mine waters and sulfurous hot streams occurred in the region of Ilısu Dam, Güçlükonak, Şırnak and Batman Province sites. Fish farming require below 1 mg/l Pb Cu and Cd and Zn in which basaltic rocks and copper ore deposites contained highly around %1-2Pb and 200 mgCu at high attitude deposits in Siirt and Şırnak. The contamination of some accumulated heavy metal contents of hot streams and soils in the region are given in

Urbanization and economic growth in the high populated Batman city evolved

along with the management of natural resources. In this process, provision of drinking water supply and distribution service for urban areas also developed on the same plane. The effective role of the public was felt in meeting the water resources management and service. Infrastructure investments are centrally located, water resources are found, structured, stored, distributed and refined. Large investments have been made in order to meet the fresh water need. The use of water resources (water withdrawal and level shift) and evaluation for development and community needs have been studied. However, the amount and quality of water that the

The dissolution concentration of accumulated metal in aliquate of high fertilizer dissolution by wrong amount of fertilizer use in theagricultural fields discharged to streams as regarding Pb heavy metal contamination is followed by equation, where

The dissolution concentration of accumulated metal in aliquate of limestone rocks dissolution by hot water streams in subground lakes with high CO2 gas dissolved streams as regarding Pb heavy metal contamination is followed by equa-

<sup>3</sup> bicarbonate concentration in effluent

4

3

3

�*ticdc* (6)

*tindc* (7)

*tin* (8)

*tin* (9)

*tin* (10)

*dcPb dt* <sup>¼</sup> *kie*

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

*dcPb dt* <sup>¼</sup> *kic*

*dcPb dt* <sup>¼</sup> *kic*

*dcPb dt* <sup>¼</sup> *kic*

*dcPb dt* <sup>¼</sup> *kic*

<sup>3</sup> nitrate concentration in effluent

equation

reaction style, t is time,

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

kinetic order type

where *SO*�<sup>2</sup>

tion, where *HCO*�<sup>2</sup>

*HNO*�<sup>2</sup>

**Table 1**.

**59**

generated in the late muds close to the settled mud - water interface. ZnS and PbS, in the sulphide complex structure are much stable and retain S in the �2 state. However, the sulfate part of reaction Eq. (5) [7, 8] may cause redox effect an oxidation. Then.

$$\text{H}\_2\text{S} + 4\text{H}\_2\text{O} \rightarrow \text{SO}\_4{}^{2-} + 10\text{H}^+ + 8\text{e}^-. \tag{5}$$

The aerated and oxygen rich waters oxidizing sulphidic character metal precipitates to sulphate and chloride dissolution by unstable forms, but over ph 9 as shown in Figure electropotantial matter of waste waters provides hydroxide precipitates in soil mud. Even jarosite form precipitates occuuring in hot water streams area with redish brownish precipitates, however those type resıduals stuck over sand may become sweet salty alg fish feed even causing higher heavy metal contamination for fish farming and stream fishing. Batman province copper and lead sulphide deposits and hot streams of high sulphate come out high potential contamination [7–13] of fresh waters soueces at pH Eh diagram stability as given in **Figure 4a** and **b** folowing flood.

**Figure 4.** *(a) Eh-pH diagrams for metal Fe and (b) Eh-pH diagrams for metal Cu stability.*

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

The dissolution kinetics of soil mud particle for Pb heavy metal is followed by equation

$$\frac{dc\_{Pb}}{dt} = k\_i e^{-tic} dc\tag{6}$$

Where cPb Lead contamination mg/l, k the rate of dissolution of lead, i is the reaction style, t is time,

The dissolution concentration of accumulated metal in aliquate of lake streams as regarding Pb heavy metal contamination is followed by equation, where n is kinetic order type

$$\frac{dc\_{Pb}}{dt} = k\_i c^{\text{int}} dc \tag{7}$$

The dissolution concentration of accumulated metal in aliquate of sulfurous hot water streams as regarding Pb heavy metal contamination is followed by equation, where *SO*�<sup>2</sup> <sup>4</sup> sulphate concentration in effluent. *fi* is concentration rate of sulphate

$$\frac{dc\_{Pb}}{dt} = k\_i c^{\text{int}}.dc.f\_i \left(\text{SO}\_4^{-2}\right)^{\text{int}} \tag{8}$$

The dissolution concentration of accumulated metal in aliquate of limestone rocks dissolution by hot water streams in subground lakes with high CO2 gas dissolved streams as regarding Pb heavy metal contamination is followed by equation, where *HCO*�<sup>2</sup> <sup>3</sup> bicarbonate concentration in effluent

$$\frac{d\mathcal{L}\_{Pb}}{dt} = k\_i c^{\text{int}} \, dc \, f\_i \left(\text{HCO}\_3^{-2}\right)^{\text{int}} \tag{9}$$

The dissolution concentration of accumulated metal in aliquate of high fertilizer dissolution by wrong amount of fertilizer use in theagricultural fields discharged to streams as regarding Pb heavy metal contamination is followed by equation, where *HNO*�<sup>2</sup> <sup>3</sup> nitrate concentration in effluent

$$\frac{d\mathcal{L}\_{Pb}}{dt} = k\_i \mathcal{c}^{\text{int}}.d\boldsymbol{c}.f\_i \left(\mathrm{HNO}\_3^{-2}\right)^{\text{int}} \tag{10}$$

The dissolution rates of heavy metals in acidic mine waters and sulfurous hot streams occurred in the region of Ilısu Dam, Güçlükonak, Şırnak and Batman Province sites. Fish farming require below 1 mg/l Pb Cu and Cd and Zn in which basaltic rocks and copper ore deposites contained highly around %1-2Pb and 200 mgCu at high attitude deposits in Siirt and Şırnak. The contamination of some accumulated heavy metal contents of hot streams and soils in the region are given in **Table 1**.

Urbanization and economic growth in the high populated Batman city evolved along with the management of natural resources. In this process, provision of drinking water supply and distribution service for urban areas also developed on the same plane. The effective role of the public was felt in meeting the water resources management and service. Infrastructure investments are centrally located, water resources are found, structured, stored, distributed and refined. Large investments have been made in order to meet the fresh water need. The use of water resources (water withdrawal and level shift) and evaluation for development and community needs have been studied. However, the amount and quality of water that the

which form very insoluble sulfide compounds. FeS is unstable relative to pyrite and the further reaction, which is an oxidation of S2� to S�, as given in Eq. (4);

generated in the late muds close to the settled mud - water interface. ZnS and PbS,

The aerated and oxygen rich waters oxidizing sulphidic character metal precipitates to sulphate and chloride dissolution by unstable forms, but over ph 9 as shown in Figure electropotantial matter of waste waters provides hydroxide precipitates in soil mud. Even jarosite form precipitates occuuring in hot water streams area with redish brownish precipitates, however those type resıduals stuck over sand may become sweet salty alg fish feed even causing higher heavy metal contamination for fish farming and stream fishing. Batman province copper and lead sulphide deposits and hot streams of high sulphate come out high potential contamination [7–13] of fresh waters soueces at pH Eh diagram stability as given in

in the sulphide complex structure are much stable and retain S in the �2 state. However, the sulfate part of reaction Eq. (5) [7, 8] may cause redox effect an oxida-

H2S þ 4H2O ! SO4

*(a) Eh-pH diagrams for metal Fe and (b) Eh-pH diagrams for metal Cu stability.*

*Batman province some set reveals the potential flood ban and flood risk.*

tion. Then.

**Figure 4.**

**58**

**Figure 3.**

*Clay Science and Technology*

**Figure 4a** and **b** folowing flood.

FeS þ S ! FeS2 (4)

<sup>2</sup>� <sup>þ</sup> 10H<sup>þ</sup> <sup>þ</sup> 8e�*:* (5)


social) in the metropolitan cities which are especially migrating in our country and in medium size settlements Such as equipment as directed by location decisions; It also determines the water demand of the city at the same time with its population and density of buildings and its quality and quantity of usage. While city plans shape the socio-economic and physical structure of the city, with the proposed land use, employment, population and density decisions, the city's daily water demand is also shaped. Therefore, any kind of urban development outside the plan creates an unhealthy environment that affects the quality of life of the city, as well as poses a serious threat to the water resources (increased water consumption pressure and pollution) (Urban Planning Chamber Water Commission, 2006). Survey, planning (feasibility) and Project work will be given efficiency. The quality of the water quality will be preserved, improved and monitored. Heavy metal contamination hazard maps will be prepared and an early warning system will be established. Nowadays, oil, grease and other pollutants as absorbent material in cleaned, bleach mud in food industry, in pharmacy adsorbant, as a catalyst carrier in the chemical industry and in many other industries it is used for various purposes. Clay bentonite, which is used as industrial absorbant, sepiolite, atapulgite and kaoline. This clay is good absorbant or active bentonite or montmorillonite. it is highly demand for absorbant substrate for fresh fruit drinks and brewery, water

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

tretmennts in Europe. The consumption has increased to around 5 million tonnes/ year in the 2020s while in 1994 it exceeded 2 million tons/year. In terms of bentonite and sepiolite, it is known that it has large beds and it is enough on these beds until recently research work was arried out for heavy metalcontamination. In this study, bentonite and other clays, shale and marly shale of Şırnak and absorbance properties, areas of use, production and market conditions. The bulk density of absorbant clay bentonite and atapulgite, the amount of moisture and the absorbant capacity. Bentonite and atapulgite absorbance by passing through certain processes was performed and the absorbance was measured at the mechanical strength

In general, a grainy and fine grained the raw materials described as the shale, kaoline, illite, marly chlorite and smectite alteration coverings of rich rock abrasion and carry over fresh water occurs in the basins. Kaolinite, montmorillonite, illite, chlorite, sepiolite and atapulgiteone or several quartz, cristobalite, amphibole, feldspar, calcite, magnesite, dolomite, gypsum, alunite, and natural clay containing one or more minerals heterogeneous mixtures [7]. Mineral depending on their content and chemical composition As the color of the killer, white, pink, gray, green, in various shades of yellow, blue and brown [8]. The chemical analyzes indicate that the killer is mainly silica, alumina and water can be distinguished in most cases iron, alkali and alkaline earth in quantities. In this study, montmorillon-

DTA curve and the water away from the cation between the layers. In addition,

The fact that clay and clay minerals, which constitute a significant part of the ground and underground resources of our country, are not processed sufficiently is an important issue that causes serious economic losses for our country. In order to produce clay minerals in high quality and desired properties, some processes such as acid activation, organo-clay preparation, microwave dissolution, calcination and cation exchange are used [12–15]. Acid-activated clay, known as bleaching earth, is used in scientific research as a selective retainer, catalyst, catalyst support and in the differentiation of the killer [16]. Bentonite with desired surface properties, porosity and hence retention capacity is mainly produced by dry or wet acid activation using

endothermic DTA peaks originating from the removal of H-bound shale in the samples were observed at approximately 200°C, and endothermic peaks of hydrate

bound to the Brønsted centers were observed at approximately 300°C.

change has been studied.

**61**

ite group bentonite and chain clay atapulgite used.

### **Table 1.**

*Şırnak and Batman province reveals the potential contamination scale and high contamination risk of fresh water source with flood.*

ecology need is not addressed. Everything is built on the theme of "develop-supplyuse". Parameters considered in the planning of water resources were population estimate, per capita water demand, fish farming, agricultural production, economic productivity level.

### **1.2 Fish farming in water lakes and streams**

The hazardous high level contaminants occurred in the such acidic seepages or acidified chelate mixing to streams should be neutralized by oxidizing reagents such as ozone or neutralizing alkaline washing so that resulted effluent contamination by Hg, Pb, Cr, Cd, Cu, Zn, Fe, SO4 rates were so low. The oxidation recycling of residual contaminants was not a serious threat using these parameters, future water demand forecasts are used and these estimated values are used when designing the systems to meet the demand. In this approach, the demand for water has been determined independently of the specific needs of fish farming, agricultural irrigation, and human needs, the amount of water a healthy ecosystem will need, or actual regional water availability. The next step in traditional planning is to identify projects that will reduce the gap between estimated water supply and demand. In every scale, the planning action (region, basin, city) is used for the regular and healthy spatial development uses (housing, commerce, industry, recreation, other

### *Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

social) in the metropolitan cities which are especially migrating in our country and in medium size settlements Such as equipment as directed by location decisions; It also determines the water demand of the city at the same time with its population and density of buildings and its quality and quantity of usage. While city plans shape the socio-economic and physical structure of the city, with the proposed land use, employment, population and density decisions, the city's daily water demand is also shaped. Therefore, any kind of urban development outside the plan creates an unhealthy environment that affects the quality of life of the city, as well as poses a serious threat to the water resources (increased water consumption pressure and pollution) (Urban Planning Chamber Water Commission, 2006). Survey, planning (feasibility) and Project work will be given efficiency. The quality of the water quality will be preserved, improved and monitored. Heavy metal contamination hazard maps will be prepared and an early warning system will be established.

Nowadays, oil, grease and other pollutants as absorbent material in cleaned, bleach mud in food industry, in pharmacy adsorbant, as a catalyst carrier in the chemical industry and in many other industries it is used for various purposes. Clay bentonite, which is used as industrial absorbant, sepiolite, atapulgite and kaoline. This clay is good absorbant or active bentonite or montmorillonite. it is highly demand for absorbant substrate for fresh fruit drinks and brewery, water tretmennts in Europe. The consumption has increased to around 5 million tonnes/ year in the 2020s while in 1994 it exceeded 2 million tons/year. In terms of bentonite and sepiolite, it is known that it has large beds and it is enough on these beds until recently research work was arried out for heavy metalcontamination. In this study, bentonite and other clays, shale and marly shale of Şırnak and absorbance properties, areas of use, production and market conditions. The bulk density of absorbant clay bentonite and atapulgite, the amount of moisture and the absorbant capacity. Bentonite and atapulgite absorbance by passing through certain processes was performed and the absorbance was measured at the mechanical strength change has been studied.

In general, a grainy and fine grained the raw materials described as the shale, kaoline, illite, marly chlorite and smectite alteration coverings of rich rock abrasion and carry over fresh water occurs in the basins. Kaolinite, montmorillonite, illite, chlorite, sepiolite and atapulgiteone or several quartz, cristobalite, amphibole, feldspar, calcite, magnesite, dolomite, gypsum, alunite, and natural clay containing one or more minerals heterogeneous mixtures [7]. Mineral depending on their content and chemical composition As the color of the killer, white, pink, gray, green, in various shades of yellow, blue and brown [8]. The chemical analyzes indicate that the killer is mainly silica, alumina and water can be distinguished in most cases iron, alkali and alkaline earth in quantities. In this study, montmorillonite group bentonite and chain clay atapulgite used.

DTA curve and the water away from the cation between the layers. In addition, endothermic DTA peaks originating from the removal of H-bound shale in the samples were observed at approximately 200°C, and endothermic peaks of hydrate bound to the Brønsted centers were observed at approximately 300°C.

The fact that clay and clay minerals, which constitute a significant part of the ground and underground resources of our country, are not processed sufficiently is an important issue that causes serious economic losses for our country. In order to produce clay minerals in high quality and desired properties, some processes such as acid activation, organo-clay preparation, microwave dissolution, calcination and cation exchange are used [12–15]. Acid-activated clay, known as bleaching earth, is used in scientific research as a selective retainer, catalyst, catalyst support and in the differentiation of the killer [16]. Bentonite with desired surface properties, porosity and hence retention capacity is mainly produced by dry or wet acid activation using

ecology need is not addressed. Everything is built on the theme of "develop-supplyuse". Parameters considered in the planning of water resources were population estimate, per capita water demand, fish farming, agricultural production, economic

*Şırnak and Batman province reveals the potential contamination scale and high contamination risk of fresh*

K + Na 74,52 81,46 81,7 84,52 88,6 ≥70 ≥50

Mn 2,72 3,02 1,5 0,72 1,02 ≤5 ≤5 Cu 3,33 2,41 2,4 4,33 2,41 ≤5 ≤5

The hazardous high level contaminants occurred in the such acidic seepages or acidified chelate mixing to streams should be neutralized by oxidizing reagents such as ozone or neutralizing alkaline washing so that resulted effluent contamination by Hg, Pb, Cr, Cd, Cu, Zn, Fe, SO4 rates were so low. The oxidation recycling of residual contaminants was not a serious threat using these parameters, future water demand forecasts are used and these estimated values are used when designing the systems to meet the demand. In this approach, the demand for water has been determined independently of the specific needs of fish farming, agricultural irrigation, and human needs, the amount of water a healthy ecosystem will need, or actual regional water availability. The next step in traditional planning is to identify projects that will reduce the gap between estimated water supply and demand. In every scale, the planning action (region, basin, city) is used for the regular and healthy spatial development uses (housing, commerce, industry, recreation, other

productivity level.

*water source with flood.*

**Table 1.**

**60**

**Effluent, mg/l**

Soil,ppm

**Şırnak coal mine pool**

*Clay Science and Technology*

**Şırnak, hezil stream**

Hg 34,11 48,71 52,3 54,11 40,71 Pb 10,58 24,53 23,2 20,58 11,53 Fe 4,33 7,62 5,9 9,33 5,62

Cd 24,72 9,56 10,1 4,72 19,56

As 1,10 2,44 2,8 2,10 2,44 SO4 0,57 0,37 1,9 0,67 0,55

**Güçlükonak hot stream**

Hg 8,11 4,71 12,3 14,11 4,71 4,71 4,71 Pb 10,58 14,53 23,2 12,58 11,53 5,7 5,2 Fe 40,33 70,62 59 93,3 56,2 60,62 67,62 K + Na 7,52 8,46 8,7 8,52 8,6 ≥70 ≥50 Cd 24,72 19,56 14,1 14,72 19,56 16 15 Mn 33,3 24,1 24,2 43,3 24,1 ≤25 ≤25 Cu 27,2 30,2 15,7 7,2 10,2 ≤15 ≤15 As 1,10 2,44 2,8 2,10 2,44 ≤5 ≤5 SO4 0,57 0,37 1,9 0,67 0,55 ≤15 ≤15

**Batman hot stream**

**Şırnak kasrik laguun** **Ilısu dam laguun1**

**Ilısu Dam Laguun2**

**1.2 Fish farming in water lakes and streams**

mineral acids such as H2SO4 and HCl [17]. The main purpose in acid activation is to reach the desired structure without disrupting the layered crystal structure of the clay. For this reason, the acid/clay ratio, temperature, acidity, acid concentration, type and duration of activation, kiln type and physical properties and amount of washing water are important considerations to be taken into account when performing the appropriate activation.

since bentonites carry the releasable and exchangable cations on interlayers which

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

In this study, the effect of water quality (ion type and amount in water) was subjected to the concentration and further alkali activation tests with mixed type bentonite received from Resadiye/Tokat bentonite deposit. Deionized, filtered and tap water and syntetic water including different salts namely CaCl2.2H2O, NaCl, MgCl2, KCl, FeCl3. 6H2O were used as separation media in concentration by settling and decantation. The effect of water quality on concentration and alkali activation were declared based on the pH, CEC (Cation exchange capacity), viscosity, swelling

Bentonite, the commercial name of montmorillonite from the clay minerals of the smectite group, shows colloidal properties when mixed with water, and its properties such as water swelling, high plasticity and ion exchange capacity are due

The large surface used for industrial purposesnatural materials [7]. Absorbents and adsorbents generally used bentonite; Simectite, Atapulgite, Sepiolite. It can be classified as montmorillonite. The smectite group is one of clay minerals orkill more with more or less called bentonite. Bentonite base mineralmontmorillonite is common for the killer and is a commercially used term, at least soft, containing 85% montmorillonite, is an aluminum hydrosilicate with a colloidal property. When mixed with water, density of a few solid swelling bentonite about 2.5 g/cm<sup>3</sup>

morillonite is calcium in many countries. Bentonite is a given name and the main contentwhich is montmorillonite and can change mainlycation can be defined as clay with Ca; Atapulgite, 2MgSi8O20 (H2O)4. The palygorskite expressed by the formula 4H2O an aqueous magnesium, aluminum silicate. Sepiolite is 6 Mg 9 Si 12 O 30(OH) 4 6H2O group is aqueous Mg silicate. In these mineralschannel-shaped poreswater bound to crystal structure with molecules. The clay in this group is micropore and channels and large surface areadue to the possession of various

**2.1 Absorbent of bentonite and shale/clay features-waste water soil absorbent**

Clay minerals in various industrial processes use, compositions and composi-

ceramics, color, etching, viscosity, plasticity, absorption, adsorption v.b properties of clay minerals significantly impact on the use of. Absorption can be carried out in the presence of water or other liquid. Absorbents material is water and other liquids is a sponge as material containing zeolite and shale pores and the pores of the mass

The main use of clay as an absorbent areas, ground absorbtion and cat litter, is the carrier of the drug. The high absorption capacity, the material large surface area, large pore volume, with sufficient pore size and distribution caused in developed matter of mass transfer and diffusion. In addition, its mechanical strength must increase when it gets wet. Bentonite, known as an absorbent clay, shale, sepiolite and atapulgite features have a large size absorbent material. Bentonite clay absorbance capacity, porosity, specific surface area, specific pore volume, and the pore size distribution of the acid, base and salt as well as chemical processes such as can also be increased by heat treatment [11–14]. Different absorption depending on clay type processes, for example, montmorillonite to the outer surface of the swollen hair water between the inner layers causing swelling which sorp waste water

tions are closely related. Grain size, grain shape, surface chemistry, surface

. mont-

interact with ions in water.

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

index and filtration loss.

**2. Sorption matter**

to the three-layered crystal structure [21–28].

substancesabsorbers and adsorbing capacitiesIt is high.

(solid material) such as shown in **Figures 6** and **7**.

**63**

### **1.3 Zeolite - clay compost with brønsted and lewis acid centers**

The Brønsted acid centers are mainly associated with the inner layer zone and the Lewis acid centers with clay marginal surfaces. The water molecules in the spheres surrounding the exchangeable cations are protonic depending on the degree of polarization of the metal cation and behave as Brønsted acid. In addition, the surface silanol groups (Si-OH) resulting from the breakage of the Si-O-Si bonds in the tetrahedral layer in the killer contribute to the Brønsted acid centers. Lewis acid centers are also associated with the co-shaped exchange of the Al3+ and Mg2+ cations in the octahedral layer and the Si4+ and Al3+ and Fe3+ cations in the tetrahedral layer, albit associated (**Figure 5**) [18] with metal atoms on the crystal edges. The oxygen planes in the space between the plates act as a pair of electrons, ie Lewis bases. The Hammett acid indicator technique, the n-butyl amine back titration technique and the investigation of the attachment geometry of the species such as cyclohexylamine, n-butylamine and pyridine can be used to determine the species and amount of acid centers in clay minerals rapidly [18, 19].

The increasing demand of bentonite utilization for advanced material technology and the limited reserves of high quality bentonites push the reserachers and the operators/producers to evaluate the lower quality calcium and mixed bentonites for the replacement of Na-bentonites in use. The technological properties of bentonites, however, can be upgraded by the application of concentrating and alkali activation. Mostly, wet concentration methods such as decantation, hyrocycloning and centrifuging have been applying and water quality and ion type/amount which the water carries becomes more important to controll the further activation process

**Figure 5.** *Clay structure welling manner prompts adsorption of heavy metals.*

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

since bentonites carry the releasable and exchangable cations on interlayers which interact with ions in water.

In this study, the effect of water quality (ion type and amount in water) was subjected to the concentration and further alkali activation tests with mixed type bentonite received from Resadiye/Tokat bentonite deposit. Deionized, filtered and tap water and syntetic water including different salts namely CaCl2.2H2O, NaCl, MgCl2, KCl, FeCl3. 6H2O were used as separation media in concentration by settling and decantation. The effect of water quality on concentration and alkali activation were declared based on the pH, CEC (Cation exchange capacity), viscosity, swelling index and filtration loss.

Bentonite, the commercial name of montmorillonite from the clay minerals of the smectite group, shows colloidal properties when mixed with water, and its properties such as water swelling, high plasticity and ion exchange capacity are due to the three-layered crystal structure [21–28].

### **2. Sorption matter**

mineral acids such as H2SO4 and HCl [17]. The main purpose in acid activation is to reach the desired structure without disrupting the layered crystal structure of the clay. For this reason, the acid/clay ratio, temperature, acidity, acid concentration, type and duration of activation, kiln type and physical properties and amount of washing water are important considerations to be taken into account when

The Brønsted acid centers are mainly associated with the inner layer zone and the Lewis acid centers with clay marginal surfaces. The water molecules in the spheres surrounding the exchangeable cations are protonic depending on the degree of polarization of the metal cation and behave as Brønsted acid. In addition, the surface silanol groups (Si-OH) resulting from the breakage of the Si-O-Si bonds in the tetrahedral layer in the killer contribute to the Brønsted acid centers. Lewis acid centers are also associated with the co-shaped exchange of the Al3+ and Mg2+ cations in the octahedral layer and the Si4+ and Al3+ and Fe3+ cations in the tetrahedral layer, albit associated (**Figure 5**) [18] with metal atoms on the crystal edges. The oxygen planes in the space between the plates act as a pair of electrons, ie Lewis bases. The Hammett acid indicator technique, the n-butyl amine back titration technique and the investigation of the attachment geometry of the species such as cyclohexylamine, n-butylamine and pyridine can be used to determine the species

The increasing demand of bentonite utilization for advanced material technology and the limited reserves of high quality bentonites push the reserachers and the operators/producers to evaluate the lower quality calcium and mixed bentonites for the replacement of Na-bentonites in use. The technological properties of bentonites, however, can be upgraded by the application of concentrating and alkali activation.

Mostly, wet concentration methods such as decantation, hyrocycloning and centrifuging have been applying and water quality and ion type/amount which the water carries becomes more important to controll the further activation process

**1.3 Zeolite - clay compost with brønsted and lewis acid centers**

and amount of acid centers in clay minerals rapidly [18, 19].

*Clay structure welling manner prompts adsorption of heavy metals.*

performing the appropriate activation.

*Clay Science and Technology*

**Figure 5.**

**62**

The large surface used for industrial purposesnatural materials [7]. Absorbents and adsorbents generally used bentonite; Simectite, Atapulgite, Sepiolite. It can be classified as montmorillonite. The smectite group is one of clay minerals orkill more with more or less called bentonite. Bentonite base mineralmontmorillonite is common for the killer and is a commercially used term, at least soft, containing 85% montmorillonite, is an aluminum hydrosilicate with a colloidal property. When mixed with water, density of a few solid swelling bentonite about 2.5 g/cm<sup>3</sup> . montmorillonite is calcium in many countries. Bentonite is a given name and the main contentwhich is montmorillonite and can change mainlycation can be defined as clay with Ca; Atapulgite, 2MgSi8O20 (H2O)4. The palygorskite expressed by the formula 4H2O an aqueous magnesium, aluminum silicate. Sepiolite is 6 Mg 9 Si 12 O 30(OH) 4 6H2O group is aqueous Mg silicate. In these mineralschannel-shaped poreswater bound to crystal structure with molecules. The clay in this group is micropore and channels and large surface areadue to the possession of various substancesabsorbers and adsorbing capacitiesIt is high.

### **2.1 Absorbent of bentonite and shale/clay features-waste water soil absorbent**

Clay minerals in various industrial processes use, compositions and compositions are closely related. Grain size, grain shape, surface chemistry, surface ceramics, color, etching, viscosity, plasticity, absorption, adsorption v.b properties of clay minerals significantly impact on the use of. Absorption can be carried out in the presence of water or other liquid. Absorbents material is water and other liquids is a sponge as material containing zeolite and shale pores and the pores of the mass (solid material) such as shown in **Figures 6** and **7**.

The main use of clay as an absorbent areas, ground absorbtion and cat litter, is the carrier of the drug. The high absorption capacity, the material large surface area, large pore volume, with sufficient pore size and distribution caused in developed matter of mass transfer and diffusion. In addition, its mechanical strength must increase when it gets wet. Bentonite, known as an absorbent clay, shale, sepiolite and atapulgite features have a large size absorbent material. Bentonite clay absorbance capacity, porosity, specific surface area, specific pore volume, and the pore size distribution of the acid, base and salt as well as chemical processes such as can also be increased by heat treatment [11–14]. Different absorption depending on clay type processes, for example, montmorillonite to the outer surface of the swollen hair water between the inner layers causing swelling which sorp waste water

waters: soma factory, airplane hangars, ship buildingbenches, other production facilities andIn the workshops, grease, oil, water, chemicals and other undesirable

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

**2.3 Microwave treated briqutting of biomass char/zeolite composite**

**3.1 Zeolite/carbon compost washing technology - sorbent applications**

**Sımak marly shalestone**

S03 0,32 0,21 0,20 0,32

*The chemical analvsis values of limestone, marly shale stone and clavstone of Şırnak province.*

The chemical compositions of used local rock materials in waste sludge

SiO2 3,53 9.42 24,14 48,53 48,53 Al203 2,23 6,53 12,61 24,61 24,61 Fe2O3 0,59 4.48 7,34 7,59 7,59 CaO 49,48 39,23 29,18 9.48 9,48 MgO 2,20 2,28 4,68 3,28 9,28 K2O 0,41 0,53 3,32 2,51 2,51 Na2O 0,35 0,24 1,11 0,35 0,35

During the experimental studies bentonite and zeolite samples, Ünye region, was investigated with intermediate type bentonite; pure, purified, tap water and

> **Şırnak marl**

46,19 26,11 21.43 6,09 0,09

**Şırnak claystone**

**Expanded clay/zeolite**

Zeoite as filler material is commonly used as cat litter, granule powder do not build up, do not spread bad smell, granule grain size, basic as absorption capacity by the cat should be accepted. High absorption capacity having clay, only to absorb the urea not ventilated, but bad reduce smell and bacteria should avoid. The grain size distribution of clay granules it is important that it is usually between 1 and 6 mm is required. The beads are in the cat's claws. and its flanks and rounded surfaces should be. Cat litter, transport and use so as not to create dust during must have

Washing of hazardous waste waters by microwave action efficiencies exceeding the total Fe Pb and Hg contents of sludges increased fast on coal char and wood char

BET specifıc surface areas, total surface activity, oxygen functional groups, total surface impurities, metal concentrations, dielectric value, free radical concentration and reactivity were related to the stimulation of oxidation reactivity. However, in some investigations, the pore size distribution of activated carbon is alsa likely to

substances absorbed and cleaned.

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

mechanical stamina [21].

were also reported by Tosun [13].

affect desorption kinetics [22–26].

**3. Material and methods**

treatment (**Table 3**) [23].

**% Sorbent Şırnak**

lgnition Loss

**Table 3.**

**65**

**limestone**

*2.3.1 Physical surface properties of char*

**Figure 6.** *The composite sorbent use, zeolite distribution in pellet.*

### **Figure 7.** *The micro pictures Şırnak marly shale char shale as sorbent.*

contamination. Sepiolite and atapulgite water absorption in a chain structure outer surfaces and zeolitic channels. In this type of structure of caged crystals there are no swelling between. The feature of the absorptive fluid is that the clay granules affect the absorption capacity. Liquid density, viscosity and surface capillary absorption of tensile clay granules are important factors affecting.

The absorbant clay bentonite was sorptive, colloidal, catalytic and rheological properties as given in **Table 2** [15]. Work in industrial waste watercleaning areas, non-burning, slippery to create a safe working environment absorbant killer is used [16–18, 28]. In the amount of clay used for hazardous waste water treatment increased over more than 180,000 tons/year.

### **2.2 Zeolite/asphaltite shale char composite**

This area is especially montmorillonite, bentonite type clay used waste water treatmnent. The floor of the bentonite granules use as absorbant in 2020s started, but until the 2nd world war did not show improvement. The industrial waste


*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

waters: soma factory, airplane hangars, ship buildingbenches, other production facilities andIn the workshops, grease, oil, water, chemicals and other undesirable substances absorbed and cleaned.

Zeoite as filler material is commonly used as cat litter, granule powder do not build up, do not spread bad smell, granule grain size, basic as absorption capacity by the cat should be accepted. High absorption capacity having clay, only to absorb the urea not ventilated, but bad reduce smell and bacteria should avoid. The grain size distribution of clay granules it is important that it is usually between 1 and 6 mm is required. The beads are in the cat's claws. and its flanks and rounded surfaces should be. Cat litter, transport and use so as not to create dust during must have mechanical stamina [21].

### **2.3 Microwave treated briqutting of biomass char/zeolite composite**

Washing of hazardous waste waters by microwave action efficiencies exceeding the total Fe Pb and Hg contents of sludges increased fast on coal char and wood char were also reported by Tosun [13].

### *2.3.1 Physical surface properties of char*

BET specifıc surface areas, total surface activity, oxygen functional groups, total surface impurities, metal concentrations, dielectric value, free radical concentration and reactivity were related to the stimulation of oxidation reactivity. However, in some investigations, the pore size distribution of activated carbon is alsa likely to affect desorption kinetics [22–26].

### **3. Material and methods**

### **3.1 Zeolite/carbon compost washing technology - sorbent applications**

The chemical compositions of used local rock materials in waste sludge treatment (**Table 3**) [23].

During the experimental studies bentonite and zeolite samples, Ünye region, was investigated with intermediate type bentonite; pure, purified, tap water and


**Table 3.**

*The chemical analvsis values of limestone, marly shale stone and clavstone of Şırnak province.*

contamination. Sepiolite and atapulgite water absorption in a chain structure outer surfaces and zeolitic channels. In this type of structure of caged crystals there are no swelling between. The feature of the absorptive fluid is that the clay granules affect the absorption capacity. Liquid density, viscosity and surface capillary absorption of

The absorbant clay bentonite was sorptive, colloidal, catalytic and rheological properties as given in **Table 2** [15]. Work in industrial waste watercleaning areas, non-burning, slippery to create a safe working environment absorbant killer is used [16–18, 28]. In the amount of clay used for hazardous waste water treatment

This area is especially montmorillonite, bentonite type clay used waste water treatmnent. The floor of the bentonite granules use as absorbant in 2020s started, but until the 2nd world war did not show improvement. The industrial waste

Unye bentonite 800–980 kg/cm<sup>3</sup> Sepiolite 400–700 Zolite 700

tensile clay granules are important factors affecting.

increased over more than 180,000 tons/year.

*The micro pictures Şırnak marly shale char shale as sorbent.*

*The composite sorbent use, zeolite distribution in pellet.*

**Figure 6.**

*Clay Science and Technology*

**Figure 7.**

**Table 2.**

**64**

**2.2 Zeolite/asphaltite shale char composite**

*Shale and Marly shale bentonite properties.*

CaCl2.2H2O, NaCl, MgCl2, KCl, AlCl3 at concentrations ranging from 31,125 to 1000 ppm. Bentonite suspensions prepared by adding synthetic waters such as 6H2O and bentonite suspensions were decanted by sedimentation method for 30 minutes in a 2 lt scale and bentonite concentrates were obtained and then necessary test and characterization procedures were applied afterwards.

Decantation was carried out in 2000 ml mills by adding 75 gr bentonite to 1900 ml of water. For a homogeneous suspension mortar, the bentonite water mixture was first subjected to scrub treatment in a Denver flotation cell for 5 minutes.

After the scurvy, the suspension was allowed to stand for 30 minutes after being agitated so that the impurities were precipitated. At the end of the period, suspended bentonite concentrate was removed by titration method and etch was dried.

The same procedure was repeated with synthetic waters prepared by adding salts at concentrations ranging from 31,125 ppm to 1000 ppm, until the bentonite concentrates were obtained in sufficient quantities with pure water, tap water and purified water.

The layout of the washing cycle is somewhat simpler than that of the lime slurry: there was no water–compost washing column towers connected to the waste sludge, and the washing unit contained one single microwave radiation column can be used to perform the three decantation washing phases: roughing, scraping and cleaning. The variation of the third cycle washing was also more limited recycled by microwave act.

It has been found that the amounts of CaO and Na2O decrease due to the replacement of the Na<sup>+</sup> and Ca<sup>+</sup> releasable cations between the inde layers with the H+ ions. Mg and Fe atoms in the octahedral crystal grains and the Al atoms in the octahedral centers, as well as the Al atoms in the tetrahedral layer, as well as Al2O3, MgO and Fe2O3. Make octahedral after bentonite from X-rays data elemental analysis data suggests that even lower coordination Al atoms are present in bentonite and less in the activated clay. The activated bentonite suspensions captured high

**Run C, mg/l k1 a b** 28 0,3 0,15 1,2 20 0,24 0,22 1,7 12 0,21 0,27 2,4

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

**Run C, mg/l k1 a b** 28 0,3 0,15 1,2 20 0,24 0,22 1,7 12 0,21 0,27 2,4

Samples for this heat treated at different temperatures certain properties of the

*The change in metal sorption depending on the metal concentration incorporated in the bentonite suspensions.*

zeolite material (high absorbance capacity and not dispersed in the wet state)

level heavy metals such as Pb and Hg in the sludge (**Figure 8**).

possibility of research and results as given in **Figure 9**.

*The activated bentonite compostwith char shale of Şırnak materials.*

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

*The activated zeolite compost with char shale of Şırnak materials.*

**Table 4.**

**Table 5.**

**Figure 8.**

**67**

The simple production presented as adapted and optimized depending on the target application. The main applications are briefly described in the following sections. Although this review only focuses on state-of-the art commercially available pellet plants, it should be noted that some prospective advanced applications for heat melting of binder are currently being studied, mainly in the form of prototypes or proof-of-concepts. These innovative applications include:


### **4. Results and discussions**

### **4.1 Langmuir absorption model**

For an overview of these more innovative and prospective applications, the general common method can be given in **Tables 4** and **5**.

The first order sorption concentration at three stage cycling counted bt the eqution below:

$$
\ln c^{Pb} = 1 + \frac{k\_1 t}{1!} + \frac{k\_1 t^2}{2!} + \frac{k\_1 t^3}{3!}, \mathfrak{J}ppm < \infty < \mathfrak{J}00ppm \tag{11}
$$

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*


### **Table 4.**

CaCl2.2H2O, NaCl, MgCl2, KCl, AlCl3 at concentrations ranging from 31,125 to 1000 ppm. Bentonite suspensions prepared by adding synthetic waters such as 6H2O and bentonite suspensions were decanted by sedimentation method for 30 minutes in a 2 lt scale and bentonite concentrates were obtained and then necessary test and characterization procedures were applied afterwards.

Decantation was carried out in 2000 ml mills by adding 75 gr bentonite to 1900 ml of water. For a homogeneous suspension mortar, the bentonite water mixture was first subjected to scrub treatment in a Denver flotation cell for

bentonite concentrate was removed by titration method and etch was dried.

The variation of the third cycle washing was also more limited recycled by

prototypes or proof-of-concepts. These innovative applications include:

temperature gradients in wet gradient.

the compressive form of hot system.

*lncPb* <sup>¼</sup> <sup>1</sup> <sup>þ</sup>

general common method can be given in **Tables 4** and **5**.

*k*1*t* 1! þ *k*1*t* 2 2! þ

forming sludge in plant.

**4. Results and discussions**

eqution below:

**66**

**4.1 Langmuir absorption model**

After the scurvy, the suspension was allowed to stand for 30 minutes after being agitated so that the impurities were precipitated. At the end of the period, suspended

The same procedure was repeated with synthetic waters prepared by adding salts at concentrations ranging from 31,125 ppm to 1000 ppm, until the bentonite concentrates were obtained in sufficient quantities with pure water, tap water and

The layout of the washing cycle is somewhat simpler than that of the lime slurry: there was no water–compost washing column towers connected to the waste sludge, and the washing unit contained one single microwave radiation column can be used to perform the three decantation washing phases: roughing, scraping and cleaning.

The simple production presented as adapted and optimized depending on the target application. The main applications are briefly described in the following sections. Although this review only focuses on state-of-the art commercially available pellet plants, it should be noted that some prospective advanced applications for heat melting of binder are currently being studied, mainly in the form of

• Compost systems, in which the extrusion mold system takes advantage of

• Compression press systems, where the high load press is used to drive the

• Hot production, where the scraping power of the load system is used to drive

For an overview of these more innovative and prospective applications, the

The first order sorption concentration at three stage cycling counted bt the

*k*1*t* 3

<sup>3</sup>! , 3*ppm* <sup>&</sup>lt; *<sup>x</sup>*<sup>&</sup>lt; <sup>300</sup>*ppm* (11)

• Continous conversion systems, utilizing the high temperature binding gradients and amounts (of at least 20°C) in slurries to drive a recycle.

5 minutes.

*Clay Science and Technology*

purified water.

microwave act.

*The activated bentonite compostwith char shale of Şırnak materials.*


### **Table 5.**

*The activated zeolite compost with char shale of Şırnak materials.*

It has been found that the amounts of CaO and Na2O decrease due to the replacement of the Na<sup>+</sup> and Ca<sup>+</sup> releasable cations between the inde layers with the H+ ions. Mg and Fe atoms in the octahedral crystal grains and the Al atoms in the octahedral centers, as well as the Al atoms in the tetrahedral layer, as well as Al2O3, MgO and Fe2O3. Make octahedral after bentonite from X-rays data elemental analysis data suggests that even lower coordination Al atoms are present in bentonite and less in the activated clay. The activated bentonite suspensions captured high level heavy metals such as Pb and Hg in the sludge (**Figure 8**).

Samples for this heat treated at different temperatures certain properties of the zeolite material (high absorbance capacity and not dispersed in the wet state) possibility of research and results as given in **Figure 9**.

**Figure 8.** *The change in metal sorption depending on the metal concentration incorporated in the bentonite suspensions.*

the hot dry samples. The filtrate was filtered and dried at 80°C. Finally, 5 ml of chlorite was added to the acid activated bentonite samples, each of which was 0.01 g, and the shale was retained by exposure to methanol vapor at 60° C for 4 hours. In addition, these samples were further dried at the same temperature for 1 hour to remove weak chlorite species [22]. X-ray powder diffraction patterns of amorphous and acid activated bentonite samples were λ = 1.54050 Å wavelength Cu Kα/40 kV/40 mA RIGAKU 2200 diffractometer. Elemental analysis of the samples was performed using the ZSX 100e wavelength-separated X-ray fluorescence spectrometer (WDXRF) system with the Rigaku brand Rh anodic x-ray tube and the Rigaku SQX software package program. The specimens were stimulated with Rh anodic x-ray tube at 50 kV and 50 mA in order to reduce the damage that could occur in the samples during the measurement. PRIS Diamond brand TG/DTA thermal analyzer was used to obtain the thermal analysis curves of bentonite samples attached to pyridine. The thermal analysis curves of the samples were placed at a heating rate of 10°C/min, 5–10 mg of sample was placed in Pt crucible and taken against α-Al2O3 reference sintered at 20–700°C in air atmosphere. Again ATR spectra of the chlorite-bentonite samples were recorded in the absence of disc preparation with KBr under vacuum at a Bruker Vertex 80 V spectrometer at

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

. The surface areas of raw, activated and shale clay samples were

measured with a Quanta Chromosorb surface analyzer. The surface area was determined by measuring the thermal conductivity using a gas mixture prepared in 30%

Thermal Properties were determined PRIS Diamond brand TG/DTA thermal analyzer. Thermogravimetric (TG) and Differential Thermal (DTA) analyzes of the samples used in the experimentation were carried out for dehydratation and

The absorbance capacity of the microwave heated shale samples according to output zeolite, char shale and Ca-Bentonite experiments, the absorbance capacities were high, but high clay samples in water muddy have efficiently sorped Fe cations much. The results show that Na-Bentonite for this purpose seems unsuitable; from Breakup heat at high temperatures it must be processed but this the temperature of the absorbance has been detected. For this purpose the best result is about 400°C

*TGA analyzes of the samples were carried out for dehydratation and activitation ability in sorption.*

N2 and 70% He composition and taking into account the BET equation.

activitation ability in sorption as seen in **Figures 10** and **11**.

**4.3 Sorbent preparation for heavy metal absorption**

for Ca-Bentonite; the result is obtained at 200°C.

1700–1350 cm <sup>1</sup>

**Figure 10.**

**69**

**Figure 9.** *The change in metal sorption depending on the metal concentration incorporated in the zeolite suspensions.*

Cation exchange ability was so effective in metal sorption manner. The pH was efficient criteria in the washin column sorption.

It can be seen in the above graph, the pH decreases inversely proportional to the amount of salt added to bentonite suspension, which is much more noticeable when FeCl3 is used.

Bentonite is known to have a considerable dependence on the layer charge and edge charge pH. Therefore, a decrease in the cation exchange capacity should be expected in parallel with the decrease in pH.

The FeCl3 20 mg added bentonite solutions showed the change in cation exchange capacity (CEC, milliequivalent gram/100 gr) found in the bentonite concentrates and suspensions obtained using the precipitation-siphoning technique, depending on the salt concentration added.

### **4.2 Activation by HCl washing following methanol decay treatment under microwave radiation**

The bentonite sample used in the study was obtained from Unye Madencilik from the Unye region of Tavkutlu mine. The bentonite sample was sieved and a small part of 45 μm was used for the operation. Bentonite samples were activated with 1 and 2 M HCl solutions for 2 h at 90° C using the Batch method (using 100 ml acid solution for 5 g sample). The acid-treated samples were washed with hot deionized water to remove Cl-ions and dried in room condition.

The microwave activated bentonite used in the experimental work was provided from the district of Unye in Ordu province. For the first time, Ünye region bentonite 0.1 M 100 ml CaCl2 solutions were mixed in the beaker at room temperature for 24 hours and the filtrate was converted to the ion-exchange by applying the AgNO3 test. Acid/clay suspensions were then prepared with bentonite, which was made to be ionized, to give H2SO4/clay ratios of 2 M, These were named -bentonite. These suspensions were dried at 150 oC for 3.5 hours. 50 ml of distilled water was added to *Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

the hot dry samples. The filtrate was filtered and dried at 80°C. Finally, 5 ml of chlorite was added to the acid activated bentonite samples, each of which was 0.01 g, and the shale was retained by exposure to methanol vapor at 60° C for 4 hours. In addition, these samples were further dried at the same temperature for 1 hour to remove weak chlorite species [22]. X-ray powder diffraction patterns of amorphous and acid activated bentonite samples were λ = 1.54050 Å wavelength Cu Kα/40 kV/40 mA RIGAKU 2200 diffractometer. Elemental analysis of the samples was performed using the ZSX 100e wavelength-separated X-ray fluorescence spectrometer (WDXRF) system with the Rigaku brand Rh anodic x-ray tube and the Rigaku SQX software package program. The specimens were stimulated with Rh anodic x-ray tube at 50 kV and 50 mA in order to reduce the damage that could occur in the samples during the measurement. PRIS Diamond brand TG/DTA thermal analyzer was used to obtain the thermal analysis curves of bentonite samples attached to pyridine. The thermal analysis curves of the samples were placed at a heating rate of 10°C/min, 5–10 mg of sample was placed in Pt crucible and taken against α-Al2O3 reference sintered at 20–700°C in air atmosphere. Again ATR spectra of the chlorite-bentonite samples were recorded in the absence of disc preparation with KBr under vacuum at a Bruker Vertex 80 V spectrometer at 1700–1350 cm <sup>1</sup> . The surface areas of raw, activated and shale clay samples were measured with a Quanta Chromosorb surface analyzer. The surface area was determined by measuring the thermal conductivity using a gas mixture prepared in 30% N2 and 70% He composition and taking into account the BET equation.

Thermal Properties were determined PRIS Diamond brand TG/DTA thermal analyzer. Thermogravimetric (TG) and Differential Thermal (DTA) analyzes of the samples used in the experimentation were carried out for dehydratation and activitation ability in sorption as seen in **Figures 10** and **11**.

### **4.3 Sorbent preparation for heavy metal absorption**

The absorbance capacity of the microwave heated shale samples according to output zeolite, char shale and Ca-Bentonite experiments, the absorbance capacities were high, but high clay samples in water muddy have efficiently sorped Fe cations much. The results show that Na-Bentonite for this purpose seems unsuitable; from Breakup heat at high temperatures it must be processed but this the temperature of the absorbance has been detected. For this purpose the best result is about 400°C for Ca-Bentonite; the result is obtained at 200°C.

**Figure 10.** *TGA analyzes of the samples were carried out for dehydratation and activitation ability in sorption.*

Cation exchange ability was so effective in metal sorption manner. The pH was

*The change in metal sorption depending on the metal concentration incorporated in the zeolite suspensions.*

It can be seen in the above graph, the pH decreases inversely proportional to the amount of salt added to bentonite suspension, which is much more noticeable when

Bentonite is known to have a considerable dependence on the layer charge and edge charge pH. Therefore, a decrease in the cation exchange capacity should be

The FeCl3 20 mg added bentonite solutions showed the change in cation exchange capacity (CEC, milliequivalent gram/100 gr) found in the bentonite concentrates and suspensions obtained using the precipitation-siphoning technique,

**4.2 Activation by HCl washing following methanol decay treatment under**

deionized water to remove Cl-ions and dried in room condition.

The bentonite sample used in the study was obtained from Unye Madencilik from the Unye region of Tavkutlu mine. The bentonite sample was sieved and a small part of 45 μm was used for the operation. Bentonite samples were activated with 1 and 2 M HCl solutions for 2 h at 90° C using the Batch method (using 100 ml acid solution for 5 g sample). The acid-treated samples were washed with hot

The microwave activated bentonite used in the experimental work was provided from the district of Unye in Ordu province. For the first time, Ünye region bentonite 0.1 M 100 ml CaCl2 solutions were mixed in the beaker at room temperature for 24 hours and the filtrate was converted to the ion-exchange by applying the AgNO3 test. Acid/clay suspensions were then prepared with bentonite, which was made to be ionized, to give H2SO4/clay ratios of 2 M, These were named -bentonite. These suspensions were dried at 150 oC for 3.5 hours. 50 ml of distilled water was added to

efficient criteria in the washin column sorption.

expected in parallel with the decrease in pH.

depending on the salt concentration added.

**microwave radiation**

FeCl3 is used.

**68**

**Figure 9.**

*Clay Science and Technology*

Pb compounds, one of the most common Hg pollutants, combine with water droplets within sulfuric acid aliquates or acid rain. Acidic mibe waters such as acidic rainfalls affect the chemical structure and biological conditions of the lakes and soil [22]. In addition, Pb Hg emissions are extremely harmful to health and directly

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

Although the changes in the structural properties of bentonites after acid activation have been studied extensively in the literature, the studies on Pb adsorption of these samples are rather limited [24]. For this reason, the aim of this study is to investigate the thermal Pb and Hg washed adsorption properties of bentonites after

The compost clays has substantial oxidation resistance and forming way service. This zero-pressure fluid provides precise, uniform temperature control to 500°C in closed-loop microwave systems where the heat transfer fluid is more than occasionally exposed to air. The fluid is comprised of a unique high-stability base plus

In the sorbent size distrşbution, 80% of weights of samples were under 3 mm. The lignite samples were mainly distributed between 1 mm and 3 mm size fractions. The effect of particle size of solid sorbents were investigated over the combustion of Şırnak Asphaltite char shale and bentonite carried out well on acidic mine water of copper mine in Siirt substance subjected to reaction with bentonite clay in sorption,

Although metal diffusion on sorbent from waste sludge was befieved to be the primary mass transport process in the absorption chamber, complex reactions proliferated the alkali clusters below 1-2 mm size and exothermic oxidation reactions increased toxic substances in the effluent form, a relatively porous structure of bentonite clay interstitial spaces and cracks reduced below 1 mm size. The hazardous heavy metal concentrations reacted adsorbate then adsorbs to the sorbent in an certain amount that is equal to the amount of previous adsorbate that was partially degraded on the surface of the bentonite clay and stuck covered toxins, along with

The waste water washing provide the main support to the clean water produc-

tion. The commercial successes in clay mud mentioned in washed bed and its

*Schematic view of an washing with microwave recycled by microwave sorption technique.*

avoiding chelating organic matter related carbonil and amine.

**4.6 Washing sorption by clay compost control**

affect the eyes, throat and respiratory tract [23].

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

acid modification and microwave activation.

high-performance oxidation inhibitor/stabilizer.

**4.5 Carbon surface activation**

as shown in **Figure 12**.

**Figure 12.**

**71**

**Figure 11.** *DT analyzes of the samples were carried out for dehydratation and activitation ability in sorption.*

The current use of absorbent clay and new areas of use increase in demand due to outflow. Especially absorbent clay market, the cat and cat market A significant improvement in America It was. For absorbent clay deposits our wealthy country, too, to have a significant share of there is no reason why. This absorbent is limited to meet clay consumption. The number of welding to, Turkey clays alternative can create resources. For this purpose, existing in Turkey absorbant clay beds must be fully identified, potential sources should be determined, absorbant purposefulness should be investigated and suitable properties absorbent clay production. Detailed studies to improve processesIt should be done. This study result, Turkey absorbanceon the samples taken from the By applying the processes, Afnor standardssuitable industrial absorbant clay productionIt was possible. Turkey's evaluating the existing potential to take part in this market, the country economywill provide significant benefits in terms of Compliance with environmental norms.

### **4.4 Compost of zeolite/shale/carbon pellets for heavy metal controls in waste waters**

Bentonite is one of the clay minerals containing montmorillonite. Structurally, montmorillonite has a 2:1 layer of alumina octahedral (O) layer between two silica tetrahedral (T) layers [18]. The negatively charged excess coming from the isomorphic shifts is compensated by the interchangeable cations in the layers [18, 19, 28].

The acid activation process is widely used to improve the adsorption and catalytic properties of natural bentonites. The impurities, such as calcite and dolomite, are removed from the structure by the treatment of montmorillonite with inorganic acids, the interchangeable cations are replaced by hydrogen ions, and some of the Al ions in the tetrahedral layer dissolve certain cations of Fe, Al and Mg in the octahedral layer [19].

As a result, acid activation increases the pore diameters of the bentonite surface and the surface area and adsorption capacity up to a certain amount of this application [20]. If the amount of acid used during the acid activation process is excessively high, the Al ions found in the octahedral layer dissolve more and as a result, the mineral structure collapses, leaving a skeleton structure composed of silica solids. This reduces the adsorption capacity of the clay and disrupts its selectivity.

Pb is a colorless and Hg. The main sources are fossil fuels such as Pb, acidic mine waters and toxic metal sludges, which are industrial plants and industrial steel washings. [21] during the metal smelting processes and other industrial processes.

### *Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

Pb compounds, one of the most common Hg pollutants, combine with water droplets within sulfuric acid aliquates or acid rain. Acidic mibe waters such as acidic rainfalls affect the chemical structure and biological conditions of the lakes and soil [22]. In addition, Pb Hg emissions are extremely harmful to health and directly affect the eyes, throat and respiratory tract [23].

Although the changes in the structural properties of bentonites after acid activation have been studied extensively in the literature, the studies on Pb adsorption of these samples are rather limited [24]. For this reason, the aim of this study is to investigate the thermal Pb and Hg washed adsorption properties of bentonites after acid modification and microwave activation.

The compost clays has substantial oxidation resistance and forming way service. This zero-pressure fluid provides precise, uniform temperature control to 500°C in closed-loop microwave systems where the heat transfer fluid is more than occasionally exposed to air. The fluid is comprised of a unique high-stability base plus high-performance oxidation inhibitor/stabilizer.

### **4.5 Carbon surface activation**

The current use of absorbent clay and new areas of use increase in demand due to

outflow. Especially absorbent clay market, the cat and cat market A significant improvement in America It was. For absorbent clay deposits our wealthy country, too, to have a significant share of there is no reason why. This absorbent is limited to meet clay consumption. The number of welding to, Turkey clays alternative can create resources. For this purpose, existing in Turkey absorbant clay beds must be fully identified, potential sources should be determined, absorbant purposefulness should be investigated and suitable properties absorbent clay production. Detailed

*DT analyzes of the samples were carried out for dehydratation and activitation ability in sorption.*

studies to improve processesIt should be done. This study result, Turkey absorbanceon the samples taken from the By applying the processes, Afnor

**waters**

**Figure 11.**

*Clay Science and Technology*

octahedral layer [19].

**70**

standardssuitable industrial absorbant clay productionIt was possible. Turkey's evaluating the existing potential to take part in this market, the country economywill provide significant benefits in terms of Compliance with environmental norms.

**4.4 Compost of zeolite/shale/carbon pellets for heavy metal controls in waste**

Bentonite is one of the clay minerals containing montmorillonite. Structurally, montmorillonite has a 2:1 layer of alumina octahedral (O) layer between two silica tetrahedral (T) layers [18]. The negatively charged excess coming from the isomorphic shifts is compensated by the interchangeable cations in the layers [18, 19, 28]. The acid activation process is widely used to improve the adsorption and catalytic properties of natural bentonites. The impurities, such as calcite and dolomite, are removed from the structure by the treatment of montmorillonite with inorganic acids, the interchangeable cations are replaced by hydrogen ions, and some of the Al ions in the tetrahedral layer dissolve certain cations of Fe, Al and Mg in the

As a result, acid activation increases the pore diameters of the bentonite surface and the surface area and adsorption capacity up to a certain amount of this application [20]. If the amount of acid used during the acid activation process is excessively high, the Al ions found in the octahedral layer dissolve more and as a result, the mineral structure collapses, leaving a skeleton structure composed of silica solids. This reduces the adsorption capacity of the clay and disrupts its selectivity. Pb is a colorless and Hg. The main sources are fossil fuels such as Pb, acidic mine

waters and toxic metal sludges, which are industrial plants and industrial steel washings. [21] during the metal smelting processes and other industrial processes.

In the sorbent size distrşbution, 80% of weights of samples were under 3 mm. The lignite samples were mainly distributed between 1 mm and 3 mm size fractions. The effect of particle size of solid sorbents were investigated over the combustion of Şırnak Asphaltite char shale and bentonite carried out well on acidic mine water of copper mine in Siirt substance subjected to reaction with bentonite clay in sorption, as shown in **Figure 12**.

Although metal diffusion on sorbent from waste sludge was befieved to be the primary mass transport process in the absorption chamber, complex reactions proliferated the alkali clusters below 1-2 mm size and exothermic oxidation reactions increased toxic substances in the effluent form, a relatively porous structure of bentonite clay interstitial spaces and cracks reduced below 1 mm size. The hazardous heavy metal concentrations reacted adsorbate then adsorbs to the sorbent in an certain amount that is equal to the amount of previous adsorbate that was partially degraded on the surface of the bentonite clay and stuck covered toxins, along with avoiding chelating organic matter related carbonil and amine.

### **4.6 Washing sorption by clay compost control**

The waste water washing provide the main support to the clean water production. The commercial successes in clay mud mentioned in washed bed and its

A decantation bed thickner was used in compost sorption process was tested at a

These cheap alkali sorbent fınes may be so feasible at the side of cost and sorbent

The approach of sorption kinetics assumed basically that the process exponentially was developed itself, as seen in **Figure 8** with specifıc features. The elimination of Pb and Hg in waste waters with clay compost sorbent was a decisive sorbent for the reaction path on the kinetics of washing acidic mine waters. Therefore a static model of washing decantation was developed at 1 mm of coal sand size. Lnstead of fluid bed combustion, packed bed column of coarse size composts and

production. The high amount toxicity of hazardous waste slurries of cyanide in recovery of Au and hot water streams might be reduced by massive alkali sorbent use [13]. Advanced column washing by char of Turkish lignite and wood char may be feasible. However, the washing with solid expanded clay soaked alkali fıne char of Turkish lignites can be utilized [14]. The heavy metal and toxic contaminants of waste waters, nitrates nitrites pesticides and Hg with clay soaked at high elimina-

scale of 2–3 kg/h; collecting operational and design data to build an industrial installation. A technological diagram of the compost washing at three stage process developed unit was made. Activated shale destruction almost observed at third cycled end. Heavy metal concentration change increased from 2nd cycle with performance of 60–70% and also simultaneous dilution of waste mud products by sedimented. it is necessary to optimize the cycling stages on metal circulation

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

without the metal concentration change.

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

**5.1 Sorbent composite char/salt method**

tion rates ranging 52–64%.

**Figure 14.**

**73**

*Thermal stability of raw and activated bentonites with chlorite of char shale.*

**Figure 13.**

*The washing decantation by sorbent use, leaching in microwave activation as sorbent compost.*

sedimentation ability were described some of the emerging applications in lime use like clean water neutralization, aeration [26]. The figures of statistical potential of washing control with different techniques in waste water cleaning are classified as seen in **Figure 13** regarding cycling decantation time.

Some cost evaluations covering security of supply and environmental impacts, climate change evaluations, and technical and economic analysis, may be disussed in cycling cost and activities [29–32].

Initially, most of the toxin removal occurs through chemical adsorption of the toxins to the expanded clay where the combustion temperature was in the combustion phase below 750°C that lasts approximately 2–3 mins. The removal efficiency of 40–90% were reported during this temperature range. Total organic toxin substances were completely slightly at efficiencies of 75–90% in the late combustion phase. The pictures of zeolite fines soaked in char shale/clay were illustrated in **Figures 9** and **10**. Following the combustion at 800°C adsorbed film of emissions over expanded clay was shown in **Figure 13**.

A common industrial combustion to control the emissions pro combustion stage lime washing involves backwashing with air and hydrated lime water rinse. Process variables include the control backwash rate, surface wash rate/duration, time sequence and duration of backwash. Clean filtrate is pumped back into the bottom of the column during backwashing.

### **5. Waste water treatment**

The required test and characterization procedures such as pH viscosity measurement, filtration loss and swelling index were applied to all bentonite concentrates obtained and then to products activated with 0.5% soda.

These sorbents need to be accurately mixed with combustion matter and to optimize the combustion process. Reliable models, based on the above results, need ta be combustion chamber construction far the estimation of kinetic parameters for toxic stream control. Such toxic stream circulation models would aid in the microwave activated shale clay sorbent use in waste water treatment systems as shown in **Figure 8**.

The country needs the cleanest fuel to be produced providing the essential oils and gases. For this reason, acidic mine waters as heavy metal contamination to control fish farming were mixed with expanded clay at 1–2 mm size soaked with slurries of different alkali sorbents such as bentonite, shale fine, NaCl, CaCl2 and KCl were tested in the packed bed column washing and the test results were illustrated in **Figure 10**.

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

A decantation bed thickner was used in compost sorption process was tested at a scale of 2–3 kg/h; collecting operational and design data to build an industrial installation. A technological diagram of the compost washing at three stage process developed unit was made. Activated shale destruction almost observed at third cycled end. Heavy metal concentration change increased from 2nd cycle with performance of 60–70% and also simultaneous dilution of waste mud products by sedimented. it is necessary to optimize the cycling stages on metal circulation without the metal concentration change.

### **5.1 Sorbent composite char/salt method**

sedimentation ability were described some of the emerging applications in lime use like clean water neutralization, aeration [26]. The figures of statistical potential of washing control with different techniques in waste water cleaning are classified as

*The washing decantation by sorbent use, leaching in microwave activation as sorbent compost.*

Some cost evaluations covering security of supply and environmental impacts, climate change evaluations, and technical and economic analysis, may be disussed

Initially, most of the toxin removal occurs through chemical adsorption of the toxins to the expanded clay where the combustion temperature was in the combustion phase below 750°C that lasts approximately 2–3 mins. The removal efficiency of 40–90% were reported during this temperature range. Total organic toxin substances were completely slightly at efficiencies of 75–90% in the late combustion phase. The pictures of zeolite fines soaked in char shale/clay were illustrated in **Figures 9** and **10**. Following the combustion at 800°C adsorbed film of emissions

A common industrial combustion to control the emissions pro combustion stage lime washing involves backwashing with air and hydrated lime water rinse. Process variables include the control backwash rate, surface wash rate/duration, time sequence and duration of backwash. Clean filtrate is pumped back into the bottom

The required test and characterization procedures such as pH viscosity measurement, filtration loss and swelling index were applied to all bentonite concen-

These sorbents need to be accurately mixed with combustion matter and to optimize the combustion process. Reliable models, based on the above results, need ta be combustion chamber construction far the estimation of kinetic parameters for toxic stream control. Such toxic stream circulation models would aid in the microwave activated shale clay sorbent use in waste water treatment systems as shown in

The country needs the cleanest fuel to be produced providing the essential oils and gases. For this reason, acidic mine waters as heavy metal contamination to control fish farming were mixed with expanded clay at 1–2 mm size soaked with slurries of different alkali sorbents such as bentonite, shale fine, NaCl, CaCl2 and KCl were tested in the packed bed column washing and the test results were

trates obtained and then to products activated with 0.5% soda.

seen in **Figure 13** regarding cycling decantation time.

in cycling cost and activities [29–32].

**Figure 13.**

*Clay Science and Technology*

over expanded clay was shown in **Figure 13**.

of the column during backwashing.

**5. Waste water treatment**

**Figure 8**.

**72**

illustrated in **Figure 10**.

These cheap alkali sorbent fınes may be so feasible at the side of cost and sorbent production. The high amount toxicity of hazardous waste slurries of cyanide in recovery of Au and hot water streams might be reduced by massive alkali sorbent use [13]. Advanced column washing by char of Turkish lignite and wood char may be feasible. However, the washing with solid expanded clay soaked alkali fıne char of Turkish lignites can be utilized [14]. The heavy metal and toxic contaminants of waste waters, nitrates nitrites pesticides and Hg with clay soaked at high elimination rates ranging 52–64%.

The approach of sorption kinetics assumed basically that the process exponentially was developed itself, as seen in **Figure 8** with specifıc features. The elimination of Pb and Hg in waste waters with clay compost sorbent was a decisive sorbent for the reaction path on the kinetics of washing acidic mine waters. Therefore a static model of washing decantation was developed at 1 mm of coal sand size. Lnstead of fluid bed combustion, packed bed column of coarse size composts and

**Figure 14.** *Thermal stability of raw and activated bentonites with chlorite of char shale.*

asphaltite char shale and bentonite applied and by the replacement of the interchangeable cations by the H+ cation. The increase in the surface area of the ben-

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

As the acid molarity increased, it was determined that the acid-modified Bentonite (0.84 ppm) and Zeolite (0.69 ppm) samples adsorbed more Pb than the

Due to the removal of octahedral cations after acid activation, the formation of new acid sites in the clay lamella structure increased the specific surface area and porosity. Therefore, the structure of bentonite showed more Pb and Fe adsorption properties. In this study, the Pb adsorption capacity of bentonite samples prepared

Analyzes were performed using approximately 30 mg of sample at a temperature range of 30–1000°C at a heating rate of 10°C/min. The temperature ranges and mass loss values obtained from the TG analysis are given in **Table 6**. The endothermic peaks observed in the DTA curves of the natural Bentonite, char shale and zeolite samples at 105, 299 and 98°C, respectively. There are due to the removal of

The shift of endothermic peak temperatures to lower values with increasing acid concentration was also observed. TGA analysis of natural bentonite, coal char shale and zeolite samples revealed that the total mass losses at 1000°C were 9.19%,

This high divergence was the endothermic peak at 150°C in DTA. In addition, in the TGA curve, a mass loss of 4.3% at 200–320° C is the endothermic peak at 270°C in DTA. This mass loss is due to the removal of hydrate and sulphate bound to Brønsted acid centers. In addition, mass loss of 4.9% in the range of 390–650°C due to dehydroxylation of the crystal lamella layers is in the form swelling easily on an

In the pH measurements made, the pH value of 7,3 in washing hazardous waste water finally at the last washing column decreased to 5, depending on the concen-

In the thre stage microwave activated washing test measurements made with tap water, it was found that 73 mg/l (ppm) in bentonite/asphaltite char shale decreased

In clean water aliquate had the 24 ppm Pb,5 ppm Hg and 57 Fe values, which Pb reduction rates of sorption at Langmuir model with nitrate washed, was 0,73 ppm/

Kaolin (%) 47.85 37.60 0.83 0.17 0.97 0.57 0.74 11.27 Şırnak Asphaltite Char Shale 47.85 37.60 0.83 0.17 0.97 0.57 0.74 11.27 Bentonite 47.85 37.60 0.83 0.17 0.97 0.57 0.74 11.27 Marly Shale 47.85 37.60 0.83 0.17 0.97 0.57 0.74 11.27 Zeolite 47.85 37.60 0.83 0.17 0.97 0.57 0.74 11.27

**SiO2 Al2O2 Fe2O2 MgO K2O CaO TiO2 LOI\***

to 53 mg/l (ppm)/in last column output. Likewise, the washed waste waters obtained after 100 min washing by microwave activaty using sodium salts softed flow with 1 mm sorbent packages showed reductions in Pb, Hg and Fe at 47%

min.l, Hg and total Fe reduction rate has decreased to 0,43 ppm/min.l and

tonite type after acid modification heay metal sorption 54%.

with 100 min circulation was found to be the sufficient washing.

natural form B (0.66 ppm).

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

physically adsorbed water.

performance.

*\**

**75**

**Table 6.**

0,23 ppm/min.l, respectively.

*LOI: Loss on Ignition at 1000°.*

*Sorbent Clay Types for waste water treatment.*

47.75% and 8.15%, respectively.

endothermic peak of 621°C centered on DTA.

tration of salt content of sorbents in the water.

**Figure 15.** *Thermal sorption quality and activated zeolite with chlorite of char shale.*

packages wass highly governed by slow washing, sufficiently sorbtion of toxic sludges.

As seen in **Figure 13**, the activated clay - zeolite examined was more efficient as an absorbent for a conversion of waste waters to friendly watres. It can be a promising waste contaminated waters, municipal wastes because of high activity in the collection and leaching in the toxic solutions in the mine waters and lakes. The sorption rates reached to 74% with Şımak asphaltite shale and zeolite compost.

However, due to the presence of salt in the environment, the bentonite particles which have become dispersed and suspended must coagulate and collapse along with other large nasties, as the surface loads decrease to absolute value and approach zero load point. The high decreases in the separation efficiency in the FeCl3 medium observed in **Figure 14**.

The activation decreased in ambient pH. So, the most important ions in the bentonites are H + and OH. Therefore, the changes that may occur in pH especially at low pH H + ion adsorbed the bentonite particles to the surface and makes the surface neutral to facilitate coagulation, so the bentonite particles which are to be suspended in the precipitation conditions are also collapsed and the separation efficiency is degraded at low pH. It has been reflected as seen in **Figures 14** and **15**.

The ability of the Na<sup>+</sup> ion to hydrate and especially the Ca+2 cation to take its place easily is an important consideration.

### **6. Conclusions**

The corresponding increase in surface area can iöprove the removal of impurities in the sample due to the microwave dissolved acid treatment over zeolite/

### *Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

asphaltite char shale and bentonite applied and by the replacement of the interchangeable cations by the H+ cation. The increase in the surface area of the bentonite type after acid modification heay metal sorption 54%.

As the acid molarity increased, it was determined that the acid-modified Bentonite (0.84 ppm) and Zeolite (0.69 ppm) samples adsorbed more Pb than the natural form B (0.66 ppm).

Due to the removal of octahedral cations after acid activation, the formation of new acid sites in the clay lamella structure increased the specific surface area and porosity. Therefore, the structure of bentonite showed more Pb and Fe adsorption properties. In this study, the Pb adsorption capacity of bentonite samples prepared with 100 min circulation was found to be the sufficient washing.

Analyzes were performed using approximately 30 mg of sample at a temperature range of 30–1000°C at a heating rate of 10°C/min. The temperature ranges and mass loss values obtained from the TG analysis are given in **Table 6**. The endothermic peaks observed in the DTA curves of the natural Bentonite, char shale and zeolite samples at 105, 299 and 98°C, respectively. There are due to the removal of physically adsorbed water.

The shift of endothermic peak temperatures to lower values with increasing acid concentration was also observed. TGA analysis of natural bentonite, coal char shale and zeolite samples revealed that the total mass losses at 1000°C were 9.19%, 47.75% and 8.15%, respectively.

This high divergence was the endothermic peak at 150°C in DTA. In addition, in the TGA curve, a mass loss of 4.3% at 200–320° C is the endothermic peak at 270°C in DTA. This mass loss is due to the removal of hydrate and sulphate bound to Brønsted acid centers. In addition, mass loss of 4.9% in the range of 390–650°C due to dehydroxylation of the crystal lamella layers is in the form swelling easily on an endothermic peak of 621°C centered on DTA.

In the pH measurements made, the pH value of 7,3 in washing hazardous waste water finally at the last washing column decreased to 5, depending on the concentration of salt content of sorbents in the water.

In the thre stage microwave activated washing test measurements made with tap water, it was found that 73 mg/l (ppm) in bentonite/asphaltite char shale decreased to 53 mg/l (ppm)/in last column output. Likewise, the washed waste waters obtained after 100 min washing by microwave activaty using sodium salts softed flow with 1 mm sorbent packages showed reductions in Pb, Hg and Fe at 47% performance.

In clean water aliquate had the 24 ppm Pb,5 ppm Hg and 57 Fe values, which Pb reduction rates of sorption at Langmuir model with nitrate washed, was 0,73 ppm/ min.l, Hg and total Fe reduction rate has decreased to 0,43 ppm/min.l and 0,23 ppm/min.l, respectively.


### **Table 6.**

*Sorbent Clay Types for waste water treatment.*

packages wass highly governed by slow washing, sufficiently sorbtion of toxic

*Thermal sorption quality and activated zeolite with chlorite of char shale.*

an absorbent for a conversion of waste waters to friendly watres. It can be a

As seen in **Figure 13**, the activated clay - zeolite examined was more efficient as

However, due to the presence of salt in the environment, the bentonite particles which have become dispersed and suspended must coagulate and collapse along with other large nasties, as the surface loads decrease to absolute value and approach zero load point. The high decreases in the separation efficiency in the

promising waste contaminated waters, municipal wastes because of high activity in the collection and leaching in the toxic solutions in the mine waters and lakes. The sorption rates reached to 74% with Şımak asphaltite shale and zeolite compost.

The activation decreased in ambient pH. So, the most important ions in the bentonites are H + and OH. Therefore, the changes that may occur in pH especially at low pH H + ion adsorbed the bentonite particles to the surface and makes the surface neutral to facilitate coagulation, so the bentonite particles which are to be suspended in the precipitation conditions are also collapsed and the separation efficiency is degraded at low pH. It has been reflected as seen in **Figures 14** and **15**. The ability of the Na<sup>+</sup> ion to hydrate and especially the Ca+2 cation to take its

The corresponding increase in surface area can iöprove the removal of impurities in the sample due to the microwave dissolved acid treatment over zeolite/

sludges.

**Figure 15.**

*Clay Science and Technology*

FeCl3 medium observed in **Figure 14**.

place easily is an important consideration.

**6. Conclusions**

**74**

The swelling index and viscosity studies of compost bentonite and zeolite did not changed in packed columns washing filtered through steel meshed packages during microwave act washing.

The pH increased at washing was efficient in heavy metal sorption, the swelling index decreased, the loss of filtration increased negatively, and viscosity decreased by the addition of sodium.

In the obtained data, it was observed that sorption manner of bentonite has negatively effected by foreign ions in washing water for the activation especially total iron ion.

This result also indicated that the properties of the irrigation and fish farming water to be used during wet soil amendment of of agricultural organic soil and lake muds with wet bentonites, on waste water treatment units which friendly mud should be controlled, otherwise the contamination after discharge would be harm human health, toxicology of animal and fish feed.

### **Abbreviations**


**Author details**

Turkey

**77**

Yıldırım İsmail Tosun

Mining Engineering Department, Engineering Faculty, Şırnak University, Şırnak,

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: yildirimismailtosun@gmail.com

provided the original work is properly cited.

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

### **Author details**

The swelling index and viscosity studies of compost bentonite and zeolite did not changed in packed columns washing filtered through steel meshed packages

The pH increased at washing was efficient in heavy metal sorption, the swelling index decreased, the loss of filtration increased negatively, and viscosity decreased

In the obtained data, it was observed that sorption manner of bentonite has negatively effected by foreign ions in washing water for the activation especially

This result also indicated that the properties of the irrigation and fish farming water to be used during wet soil amendment of of agricultural organic soil and lake muds with wet bentonites, on waste water treatment units which friendly mud should be controlled, otherwise the contamination after discharge would be harm

*a* affinity parameter of the Langmuir isotherm (L mg<sup>1</sup>

*Ci* concentration of manganese in the bulk external phase of stage i

1 )

)

*C0* feed concentration of manganese in the column (mg L<sup>1</sup>

*ke* mass transfer coefficient in the bulk external phase (m s<sup>1</sup>

*qi* concentration of immobilized manganese within the adsorbent

*qm* theoretical maximum adsorption capacity of the Langmuir

) *r* radial distance from the center of the particle, *0 < r < Rp* (m)

1 )

)

*kr* reaction rate constant for heterogeneous systems (m s<sup>1</sup>

particle at stage i (mg g<sup>1</sup>

isotherm (mg g<sup>1</sup>

*Rp* radius of adsorbent particle (m) *<sup>R</sup><sup>2</sup>* determination coefficient () *rc,i* unreacted core radius at stage i (m)

ρ density of adsorbent particle (g m<sup>3</sup>

τ mean residence time of fluid in the column (s)

)

)

)

)

during microwave act washing.

human health, toxicology of animal and fish feed.

*b* stoichiometric constant defined by

)

*Def* effective diffusion coefficient (m<sup>2</sup> s

*Bim* Biot number for mass transfer

(mg L<sup>1</sup>

*B* reactant solid defined

*F* objective function *h* fixed bed height (m)

*N* number of stages

*Q* volumetric flowrate (m<sup>3</sup> s

*R* radius of column (m)

*Vi* volume of stage i (L) α backmixing coefficient () φ column hold-up ()

*t* time (s)

**76**

by the addition of sodium.

*Clay Science and Technology*

total iron ion.

**Abbreviations**

Greek symbols

Yıldırım İsmail Tosun Mining Engineering Department, Engineering Faculty, Şırnak University, Şırnak, Turkey

\*Address all correspondence to: yildirimismailtosun@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Nalbantcilar, MT, Pinarkara, SY, 2016, Public health risk assessment of groundwater contamination in Batman, Turkey, Water Health. 2016 Aug;**14**(4): 650-61. doi: 10.2166/wh.2016.290.

[2] Çelik, R., 2015, Temporal changes in the groundwater level in the Upper Tigris Basin, Turkey, determined by a GIS technique, Journal of African Earth Sciences, Volume 107, July 2015, Pages 134–143

[3] Disli, E., 2017, Hydrochemical characteristics of surface and groundwater and suitability for drinking and agricultural use in the Upper Tigris River Basin, Diyarbakir—Batman, Turkey, Springer, 2017, Environmental Earth Sciences **76**(14), DOI: 10.1007/ s12665-017-6820-5

[4] S. Ahamed, A. Hussam, A.K.M. Munir, 2009, Groundwater Arsenic Removal Technologies Based on Sorbents: Field Applications and Sustainability, Handbook of Water Purity and Quality, Academic Press, Amsterdam (2009) 379–417

[5] J.S. Ahn, C.M. Chon, H.S. Moon, K. W. Kim, 2003, Arsenic removal using steel manufacturing by-products as permeable reactive materials in mine tailing containment systems, Water Research, **37** (2003), pp. 2478–2488

[6] J.P. Allen, I.G. Torres, 1991, Physical separation techniques for contaminated sediment, N.N. Li (Ed.), Recent Developments in Separation Science, CRC Press, West Palm Beach, FL (1991)

[7] S.J. Allen, L.J. Whitten, M. Murray, O. Duggan, 1997, The adsorption of pollutants by peat, lignite and activated chars, Journal of Chemical Technology & Biotechnology, **68** (1997), pp. 442–452

[8] E. Álvarez-Ayuso, H.W. Nugteren, 2005, Purification of chromium(VI) finishing wastewaters using calcined

and uncalcined Mg-Al-CO3 hydrotalcite, Water Research, **39** (2005), pp. 2535–25

[9] R.A.I. Abou-Shanab, J.S. Angle, R.L. Chaney, 2006, Bacterial inoculants affecting nickel uptake by Alyssum murale from low, moderate and high Ni soils, Soil Biology and Biochemistry, **38** (2006), pp. 2882–2889

[16] Srivastava, R.V. 2003. Controlling of SO2 Emissions, A Review of

*DOI: http://dx.doi.org/10.5772/intechopen.94404*

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite…*

[25] Flessner, U., Jones, D.J., Roziere, J., Zajac, J., Storaro, L., Lenarda, M., Pavan, M., Lopez, A.J., Castellon, E.R., Trombetta, M., Busca, G. (2001). A Study of the Surface Acidity of Acid-Treated Montmorillonite Clay Catalyst. J. Mol. Catal. A: Chemical, **168**, 247–256.

[26] Heyding, R.D., Ironside, R., Norris, A.R., ve Prysiazniuk, R.Y. (1960). Acid Activation of Montmorillonite. Can. J.

[27] Hutson, N.D., Hoekstra, M.J., Yang, R.T. (1999). Control of Microporosity of Al2O3-Pillared Clays: Effect of pH, Calcination Temperature and Clay Cation Exchange Capacity. Micropor. Mesopor. Mater., 28, 447–459.

[28] Volzone, C., Ortiga, J. 2009. Adsorption of gaseous SO2 and structural changes of montmorillonite. Applied Clay Science, 44, 251–254

156-163

[29] Noyan H, Önal M, Sarıkaya Y. The Effect of Sulphuric Acid Activation on the Crystallinity, Surface Area, Porosity, Surface Acidty, and Bleaching Power of a Bentonite. Food Chemistry. 2007;**105**:

[30] Önal M, Sarıkaya Y, Alemdaroğlu T,

Bozdoğan İ. The Effect of Acid Activation on Some Physicochemical Properties of a Bentonite. Turkish Journal of Chemistry. 2002;**26**:409-416

[31] Reedy, C.R., Nagendrappa, G., Prakash, B.S.J. (2007). Surface Acidity Study of Mn+-Montmorillonite Clay Catalysts by FT-IR Spectroscopy:

[32] Rodriguez MAV, Barrios MS, Gonzalez JDL, Munoz MAB. Acid Activation of a Ferrous Saponite (Griffithite): Physico-Chemical Characterization and Surface Area of the Products Obtained. Clays and Clay

Minerals. 1994;**42**:724-730

Chem., 38, 1003–1016.

Technologies, Nova Science Publishers,

[17] Venaruzzo, J.L., Volzone C., Rueda

bentonitic clay minerals as adsorbents of CO, CO2 and SO2 gases. Microporous and Mesoporous Materials, **56**, 73–80.

[18] Alemdaroglu, T., Akkus, G., Önal, M., Sarikaya, Y. (2003). Investigation of the Surface Acidity of a Bentonite Modified by Acid Activation and Thermal Treatment. Turkish Journal of

[19] Benesi, H.A. (1956). Acidity of Catalyst Surfaces I. Acid Strength from Colors of Adsorbed Indicators. The Journal of Physical Chemistry, **78**,

[20] Benesi, H.A. (1957). Acidity of Catayst Surfaces II. Amine Titration Using Hammett Indicators. The Journal of Physical Chemistry, **61**, 970–973.

[21] Caglar, B., Afsin, B., Tabak, A. (2007). Benzamide Species Retained by DMSO Composites at a Kaolinite Surface. J. Therm. Anal. Cal., **87**, 429–

[22] Caglar, B., Afsin, B., Tabak, A., and Eren, E. (2009). Characterization of Cation Exchanged Bentonites by XRPD, ATR, DTA/TG and BET measurement Investigation of. Chemical Engineering

[23] Chitnis, S.R., Sharma, M.M. (1997). Industrial Applications of Acid-Treated

Clays as Catalyst. Reactive and Functional Polymers, **32**, 93–115.

[24] Christidis, G.E., Scott, P.W., Dunham, A.C. (1997). Acid Activation and Bleaching Capacity of Bentonites from the Islands of Milos and Chios, Aegean, Greece, Appl. Clay Sci., **12**,

Journal, **149**, 242–248.

M.L., Ortiga J. 2002. Modified

Inc., New York, 1 pp.

Chemistry, **27**, 675–681.

5490–5494.

432.

329–347.

**79**

[10] R.A. Abramovitch, B.Z. Huang, M. Davis, L. Peters, 2003, In situ remediation of soils contaminated with toxic metal ions using microwave energy, Chemosphere, **53** (2003), pp. 1077–1085

[11] J. Acharya, J.N. Sahu, C.R. Mohanty, B.C. Meikap, 2009, Removal of lead(II) from wastewater by activated carbon developed from Tamarind wood by zinc chloride activation, Chemical Engineering Journal, **149** (2009), pp. 249–262

[12] J. Acharya, J.N. Sahu, B.K. Sahoo, C.R. Mohanty, B.C. Meikap, 2009, Removal of chromium(VI) from wastewater by activated carbon developed from Tamarind wood activated with zinc chloride, Chemical Engineering Journal, **150** (2009), pp. 25–39

[13] Novak, I., Cicel, B. 1978. Dissolution of smectites in hydrochloric acid; II, Dissolution rate as a function of crystallochemical composition. Clays and Clay Minerals, **26**, 341–344.

[14] Önal, M., Sarikaya, Y., Alemdaroglu, T., Bozdogan, I. 2002. The effect of acid activation on some physicochemical properties of a bentonite. Turkish Journal of Chemistry, **26**, 409–416

[15] Srasra, E., Bergaya, F., van Damme, H., Arguib, N.K. 1989. Surface properties of an activated bentonite. Decolorization of rape-seed oil. Applied Clay Science, **4**, 411–421.

*Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite… DOI: http://dx.doi.org/10.5772/intechopen.94404*

[16] Srivastava, R.V. 2003. Controlling of SO2 Emissions, A Review of Technologies, Nova Science Publishers, Inc., New York, 1 pp.

**References**

*Clay Science and Technology*

134–143

s12665-017-6820-5

[1] Nalbantcilar, MT, Pinarkara, SY, 2016, Public health risk assessment of groundwater contamination in Batman, Turkey, Water Health. 2016 Aug;**14**(4): 650-61. doi: 10.2166/wh.2016.290.

and uncalcined Mg-Al-CO3 hydrotalcite, Water Research, **39**

[9] R.A.I. Abou-Shanab, J.S. Angle, R.L. Chaney, 2006, Bacterial inoculants affecting nickel uptake by Alyssum murale from low, moderate and high Ni soils, Soil Biology and Biochemistry, **38**

[10] R.A. Abramovitch, B.Z. Huang, M.

remediation of soils contaminated with toxic metal ions using microwave energy, Chemosphere, **53** (2003), pp.

[11] J. Acharya, J.N. Sahu, C.R. Mohanty, B.C. Meikap, 2009, Removal of lead(II) from wastewater by activated carbon developed from Tamarind wood by zinc

Engineering Journal, **149** (2009), pp.

[12] J. Acharya, J.N. Sahu, B.K. Sahoo, C.R. Mohanty, B.C. Meikap, 2009, Removal of chromium(VI) from wastewater by activated carbon developed from Tamarind wood activated with zinc chloride, Chemical Engineering Journal, **150** (2009), pp.

[13] Novak, I., Cicel, B. 1978. Dissolution of smectites in hydrochloric acid; II, Dissolution rate as a function of crystallochemical composition. Clays and Clay Minerals, **26**, 341–344.

[14] Önal, M., Sarikaya, Y.,

Alemdaroglu, T., Bozdogan, I. 2002. The effect of acid activation on some physicochemical properties of a bentonite. Turkish Journal of Chemistry, **26**, 409–416

[15] Srasra, E., Bergaya, F., van Damme,

H., Arguib, N.K. 1989. Surface properties of an activated bentonite. Decolorization of rape-seed oil. Applied

Clay Science, **4**, 411–421.

(2005), pp. 2535–25

(2006), pp. 2882–2889

1077–1085

249–262

25–39

Davis, L. Peters, 2003, In situ

chloride activation, Chemical

[2] Çelik, R., 2015, Temporal changes in the groundwater level in the Upper Tigris Basin, Turkey, determined by a GIS technique, Journal of African Earth Sciences, Volume 107, July 2015, Pages

[3] Disli, E., 2017, Hydrochemical characteristics of surface and

[4] S. Ahamed, A. Hussam, A.K.M. Munir, 2009, Groundwater Arsenic Removal Technologies Based on Sorbents: Field Applications and Sustainability, Handbook of Water Purity and Quality, Academic Press,

Amsterdam (2009) 379–417

[5] J.S. Ahn, C.M. Chon, H.S. Moon, K. W. Kim, 2003, Arsenic removal using steel manufacturing by-products as permeable reactive materials in mine tailing containment systems, Water Research, **37** (2003), pp. 2478–2488

[6] J.P. Allen, I.G. Torres, 1991, Physical separation techniques for contaminated

[7] S.J. Allen, L.J. Whitten, M. Murray, O.

[8] E. Álvarez-Ayuso, H.W. Nugteren, 2005, Purification of chromium(VI) finishing wastewaters using calcined

sediment, N.N. Li (Ed.), Recent Developments in Separation Science, CRC Press, West Palm Beach, FL (1991)

Duggan, 1997, The adsorption of pollutants by peat, lignite and activated chars, Journal of Chemical Technology & Biotechnology, **68** (1997), pp. 442–452

**78**

groundwater and suitability for drinking and agricultural use in the Upper Tigris River Basin, Diyarbakir—Batman, Turkey, Springer, 2017, Environmental Earth Sciences **76**(14), DOI: 10.1007/

[17] Venaruzzo, J.L., Volzone C., Rueda M.L., Ortiga J. 2002. Modified bentonitic clay minerals as adsorbents of CO, CO2 and SO2 gases. Microporous and Mesoporous Materials, **56**, 73–80.

[18] Alemdaroglu, T., Akkus, G., Önal, M., Sarikaya, Y. (2003). Investigation of the Surface Acidity of a Bentonite Modified by Acid Activation and Thermal Treatment. Turkish Journal of Chemistry, **27**, 675–681.

[19] Benesi, H.A. (1956). Acidity of Catalyst Surfaces I. Acid Strength from Colors of Adsorbed Indicators. The Journal of Physical Chemistry, **78**, 5490–5494.

[20] Benesi, H.A. (1957). Acidity of Catayst Surfaces II. Amine Titration Using Hammett Indicators. The Journal of Physical Chemistry, **61**, 970–973.

[21] Caglar, B., Afsin, B., Tabak, A. (2007). Benzamide Species Retained by DMSO Composites at a Kaolinite Surface. J. Therm. Anal. Cal., **87**, 429– 432.

[22] Caglar, B., Afsin, B., Tabak, A., and Eren, E. (2009). Characterization of Cation Exchanged Bentonites by XRPD, ATR, DTA/TG and BET measurement Investigation of. Chemical Engineering Journal, **149**, 242–248.

[23] Chitnis, S.R., Sharma, M.M. (1997). Industrial Applications of Acid-Treated Clays as Catalyst. Reactive and Functional Polymers, **32**, 93–115.

[24] Christidis, G.E., Scott, P.W., Dunham, A.C. (1997). Acid Activation and Bleaching Capacity of Bentonites from the Islands of Milos and Chios, Aegean, Greece, Appl. Clay Sci., **12**, 329–347.

[25] Flessner, U., Jones, D.J., Roziere, J., Zajac, J., Storaro, L., Lenarda, M., Pavan, M., Lopez, A.J., Castellon, E.R., Trombetta, M., Busca, G. (2001). A Study of the Surface Acidity of Acid-Treated Montmorillonite Clay Catalyst. J. Mol. Catal. A: Chemical, **168**, 247–256.

[26] Heyding, R.D., Ironside, R., Norris, A.R., ve Prysiazniuk, R.Y. (1960). Acid Activation of Montmorillonite. Can. J. Chem., 38, 1003–1016.

[27] Hutson, N.D., Hoekstra, M.J., Yang, R.T. (1999). Control of Microporosity of Al2O3-Pillared Clays: Effect of pH, Calcination Temperature and Clay Cation Exchange Capacity. Micropor. Mesopor. Mater., 28, 447–459.

[28] Volzone, C., Ortiga, J. 2009. Adsorption of gaseous SO2 and structural changes of montmorillonite. Applied Clay Science, 44, 251–254

[29] Noyan H, Önal M, Sarıkaya Y. The Effect of Sulphuric Acid Activation on the Crystallinity, Surface Area, Porosity, Surface Acidty, and Bleaching Power of a Bentonite. Food Chemistry. 2007;**105**: 156-163

[30] Önal M, Sarıkaya Y, Alemdaroğlu T, Bozdoğan İ. The Effect of Acid Activation on Some Physicochemical Properties of a Bentonite. Turkish Journal of Chemistry. 2002;**26**:409-416

[31] Reedy, C.R., Nagendrappa, G., Prakash, B.S.J. (2007). Surface Acidity Study of Mn+-Montmorillonite Clay Catalysts by FT-IR Spectroscopy:

[32] Rodriguez MAV, Barrios MS, Gonzalez JDL, Munoz MAB. Acid Activation of a Ferrous Saponite (Griffithite): Physico-Chemical Characterization and Surface Area of the Products Obtained. Clays and Clay Minerals. 1994;**42**:724-730

Section 2

Applications

**81**
