**2. Capillary electrophoresis**

without the knowledge of nanoparticles, Richard Feynman opened "nano-window of twentyfirst century" with his lecture "There's plenty of room at the bottom". This lecture came to be looked upon as the starting point of nanoscience as we are already living in [2]. In 1974, Taniguchi used the term "Nanotechnology" for the first time. This term was defined as the technology, where dimensions, within the range of 0.1–100 nm, play a key role. At the nanolevel, gravity is less an issue while the strength of materials is a bigger one and also quantum size effect is a key aspect. Due to the unique size-dependent spectroscopic, electronic, and thermal features and also chemical properties, and ability to be functionalized, arising from the small sizes and large surface-to-volume ratio, nanomaterials found their applications not only in electronics, physics, and engineering but also in natural sciences. Although nanomaterials are greatly affecting numerous scientific fields, it can be perceived differently. In chemistry, the range of sizes has been associated with colloid solutions, micelles, polymeric molecules, and also large molecules, or aggregates of number of molecules. Recently, structures such as carbon nanotubes, silicon nanorods, and semiconductor quantum dots have been emerged as particularly interesting classes of nanomaterials. In physics and electrical engineering, nanoscience is most often associated with quantum behavior, and the behavior of electrons and photons in nanoscale structures. Biochemistry and biology is interested in nanostructures such as cells components. The most widely investigated biological structures including DNA, viruses, and subcellular organelles can be considered as

It is obvious that "nano" influences the whole scientific world including instrumental analytical chemistry. Due to above-mentioned unique properties, not only new approaches and assays are being developed, but also standard techniques have been upgraded and capillary electrophoresis (CE) belongs to the group of these highly affected methods. In 1981, and since then, this powerful analytical technique progressed significantly not only in instrumentation, but also in method development, data acquisition, and processing. The group of applications has also widened markedly. The applications of CE are covering huge number of analytes from inorganic ions [4–8] and organic molecules [9–11] to biomolecules such as proteins [12–14] and DNA [15–17]. The golden era of CE was in 1990s, during the Human Genome Project [18]. The sequencing of the whole human genome was successfully finished in 2006 identifying all 20,000–25,000 genes (approximately) in human DNA and determining the sequences of 3 billion base pairs that make

Next great boom of CE begun due to the micro-total analysis system (μTAS) concept [19]. Due to the relatively simple instrumentation and ease of miniaturization of CE, the fast growth of attention in microfluidics and particularly in chip-based CE [20–23] was observed. Even though CE provides rapid results with high efficiency and resolution, and sample consumption is low; advantages of high number of theoretical plates can be diminished by relatively low sensitivity of commonly used photometric detection systems [24]. Therefore, new approaches improving these weak sites are investigated and the use of nanomaterials

nanostructures [3].

312 Novel Nanomaterials - Synthesis and Applications

up human DNA.

is widely tested.

**1.1. From nano-pottery to modern analytical tools**

Capillary electrophoresis is an extremely powerful microcolumn separation technique, separating molecules based on their mobilities in the electric field. Its main advantages include high separation efficiency, short time of analysis, and low consumption of chemicals.

Classical CE separation takes place in a fused silica capillary with internal diameter of 20–100μm, where the voltage of up to ±30 kV is applied. The scheme of the setup is shown in **Figure 1**.

Diversity of detection modalities applicable in CE is very wide. Optical detection methods including photometric and fluorimetric detection are probably the most common ones currently used in CE; however, electrochemical detection including amperometric and contactless conductometric detection have unparalleled advantages. Especially for analysis of small inorganic ions, which do not absorb light, electrochemical detection is an alternative to the indirect optical approach. Also, popularity of mass spectrometric (MS) detection coupled to CE increased rapidly in past few decades.

From the very beginning, electromigration methods benefited from the use of certain sieving media, such as paper or gel. Moreover, since the separations have been transferred to capillary and/or chip, the addition of some kind of "stationary phase", sieving media or pseudo-stationary phase increased the number of applications. This step led to rise of several electrophoretic methods such as capillary electrochromatography or capillary micellar electrokinetic chromatography.

Low sensitivity, which is probably the main weakness of CE in connection with the most wide spread detection method—spectrophotometric detection—is caused by the short optical path-length (given by the capillary diameter) and the low sample volume that is injected.

**Figure 1.** Scheme of CE setup.

Therefore, a preconcentration step is usually used for analysis of relatively diluted sample solutions. The injected sample solution should have low salt concentration to enable the sample stacking process. Otherwise the electro-osmotic flow can be altered, and the unfavorable detector background signal may be observed. Two main methods are used for sample pretreatment and preconcentration: (i) an electrophoretic method and (ii) a chromatographic technique. Electrophoretic techniques are based on differences in the electrophoretic mobilities of the analytes. Four main types of these techniques have been presented: transient isotachophoresis [25, 26], stacking [27–29], sweeping [30–32], and dynamic pH junction [33, 34]. On the other hand, chromatographic techniques rely on analyte sorption on a surface of the stationary phase. Chromatographic techniques allow for loading of large volumes followed by preconcentration on a sorbent and subsequent elution into a small volume of solvent, resulting in lower limits of detection.

high requirements on an operator, because of interpretation of the results. Therefore conventional or microfluidic CE is a good alternative for characterization of colloids and nanomaterials. Review articles focusing on electrophoretic separation of nanoparticles has been published in 2004 by Rodriguez and Armstrong [37], later by Surugau and Urban [38], Pyell [39], Lopez-Lorente et al. [40], and in 2017 by Aleksenko et al. [41]. Microfluidic format used in nanoparticle separation was reviewed by Salafi et al. [42]. More focused review article about CE analysis of poly(amidoamine) dendrimeric structures was prepared by Shi et al. [43]. Paper summarizing the application of separation techniques (including CE) of gold nanopar-

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One of the main advantages of nanomaterials is that their surface can be easily functionalized and modified with various molecules potentially applicable for interactions with other molecules. Therefore, CE can (i) monitor the interaction between nanomaterial and analyte, (ii) monitor the interaction between two analytes facilitated by the nanomaterial, and (iii) monitor the interaction between two analytes expressed as a change in the signal of the nanomaterial.

Nowadays, an increasing number of researchers perform CE separations in short capillaries (units of centimeters) instead of microfluidic chips [48, 49]. In such capillaries, fast and efficient separations are carried out without complicated chip preparation requiring expensive facilities (e.g. clean rooms and lithography). Compared with microchip-based high-speed CE systems, short capillary-based high-speed CE systems take advantage of simple structure,

The disadvantage, however, is in lowered resolution connected with short separation length. This obstacle can be solved either by injection of extremely low sample volumes (picoliters) or by additional selectivity given by stationary of pseudo-stationary phases of various natures (e.g. micelles, nanoparticles, nanostructures, etc.), which significantly eliminate the adsorption of highly abundant proteins on the capillary wall [50–53]. Nanomaterials have been proven to be effective (pseudo)stationary phase due to their beneficial properties, such as large surface– to-volume ratio and easy modification. The most commonly used nanomaterials are carbon nanotubes [54]. However, other structures including nanoparticles [55, 56], nanofibres [57], and/or nanorods [58, 59] have been utilized for these purposes. On the other hand, surfacebinding method uses interaction between analyte with the surface of fixed nanostructures such as monoliths, nanopillars, immobilized nanoparticles, and/or other nanomaterials. All of these types have already been employed in coupling with in either capillary-based CE or microfluidic CE. Immobilized nanomaterials, either deposited on capillary wall as a thin layer coating or packed within the capillary, are commonly utilized as stationary phases for capillary electrochromatography. The (pseudo)stationary phases enable a broad range of function-

ticles [44, 45] and QDs [46, 47] analysis are also accessible.

**4. Nanomaterials enhancing performance of capillary** 

**electrophoresis**

**4.1. Enhancement of separation**

easy fabrication, and low costs.

alities offering a variety of interactions [60] (**Figure 2**).

For such applications, nanomaterials are excellent candidates because, compared to bulk materials, nanomaterials offer significantly higher surface-to-volume ratios, and therefore provide higher sorption capacity and thus better extraction efficiencies. As an example, may serve the comparison of surface area of carbon microparticles with 60 μm in diameter of (0.01 mm<sup>2</sup> ) and the surface area of carbon nanoparticles with 60 nm in diameter (11.3 mm<sup>2</sup> ). Similar to the increase in the surface area, the reactivity is also increased by approximately three orders of magnitude. Not only the surface area, but also the chemical affinity may be beneficial. For example, gold nanoparticles provide excellent extraction power due to their high affinity for thiol-containing compounds.

Similarly, magnetic separation is a method using magnetism for the efficient separation mediated by paramagnetic and superparamagnetic particles. This technique takes advantage of the option of surface modification of magnetic nanoparticles to enable so-called immunoextraction. Such particles may be modified by either antibodies for specific capture of the target analyte or by oligonucleotide fragments having sequences complementary to the desired nucleic acid. Magnetic particles can be immobilized using an external magnetic field and interfering compounds are removed from the solution [35].

### **3. Capillary electrophoresis for analysis of nanomaterials**

The field of nanomaterials (e.g. metal or polymeric nanoparticles and carbon nanomaterials) is one of the most attractive and quickly emerging, while these materials have often valuable properties for various applications. The synthesis, however, is problematic especially from batch-to-batch repeatability point of view and, sometimes, techniques enabling characterization of nanomaterial properties and composition are absent. Even within a single batch, the polydispersity of the particles and the variability of their properties may present insurmountable problem for reliable application [36].

The conventional methods evaluating the size distribution are transmission electron microscopy and/or size exclusion chromatography. However, these methods have disadvantages including high instrumental costs, time consuming and laborious sample preparation, and high requirements on an operator, because of interpretation of the results. Therefore conventional or microfluidic CE is a good alternative for characterization of colloids and nanomaterials. Review articles focusing on electrophoretic separation of nanoparticles has been published in 2004 by Rodriguez and Armstrong [37], later by Surugau and Urban [38], Pyell [39], Lopez-Lorente et al. [40], and in 2017 by Aleksenko et al. [41]. Microfluidic format used in nanoparticle separation was reviewed by Salafi et al. [42]. More focused review article about CE analysis of poly(amidoamine) dendrimeric structures was prepared by Shi et al. [43]. Paper summarizing the application of separation techniques (including CE) of gold nanoparticles [44, 45] and QDs [46, 47] analysis are also accessible.

One of the main advantages of nanomaterials is that their surface can be easily functionalized and modified with various molecules potentially applicable for interactions with other molecules. Therefore, CE can (i) monitor the interaction between nanomaterial and analyte, (ii) monitor the interaction between two analytes facilitated by the nanomaterial, and (iii) monitor the interaction between two analytes expressed as a change in the signal of the nanomaterial.

## **4. Nanomaterials enhancing performance of capillary electrophoresis**

#### **4.1. Enhancement of separation**

Therefore, a preconcentration step is usually used for analysis of relatively diluted sample solutions. The injected sample solution should have low salt concentration to enable the sample stacking process. Otherwise the electro-osmotic flow can be altered, and the unfavorable detector background signal may be observed. Two main methods are used for sample pretreatment and preconcentration: (i) an electrophoretic method and (ii) a chromatographic technique. Electrophoretic techniques are based on differences in the electrophoretic mobilities of the analytes. Four main types of these techniques have been presented: transient isotachophoresis [25, 26], stacking [27–29], sweeping [30–32], and dynamic pH junction [33, 34]. On the other hand, chromatographic techniques rely on analyte sorption on a surface of the stationary phase. Chromatographic techniques allow for loading of large volumes followed by preconcentration on a sorbent and subsequent elution into a small volume of solvent,

For such applications, nanomaterials are excellent candidates because, compared to bulk materials, nanomaterials offer significantly higher surface-to-volume ratios, and therefore provide higher sorption capacity and thus better extraction efficiencies. As an example, may serve the comparison of surface area of carbon microparticles with 60 μm in diameter of

Similar to the increase in the surface area, the reactivity is also increased by approximately three orders of magnitude. Not only the surface area, but also the chemical affinity may be beneficial. For example, gold nanoparticles provide excellent extraction power due to their

Similarly, magnetic separation is a method using magnetism for the efficient separation mediated by paramagnetic and superparamagnetic particles. This technique takes advantage of the option of surface modification of magnetic nanoparticles to enable so-called immunoextraction. Such particles may be modified by either antibodies for specific capture of the target analyte or by oligonucleotide fragments having sequences complementary to the desired nucleic acid. Magnetic particles can be immobilized using an external magnetic field and interfering

The field of nanomaterials (e.g. metal or polymeric nanoparticles and carbon nanomaterials) is one of the most attractive and quickly emerging, while these materials have often valuable properties for various applications. The synthesis, however, is problematic especially from batch-to-batch repeatability point of view and, sometimes, techniques enabling characterization of nanomaterial properties and composition are absent. Even within a single batch, the polydispersity of the particles and the variability of their properties may present insurmount-

The conventional methods evaluating the size distribution are transmission electron microscopy and/or size exclusion chromatography. However, these methods have disadvantages including high instrumental costs, time consuming and laborious sample preparation, and

) and the surface area of carbon nanoparticles with 60 nm in diameter (11.3 mm<sup>2</sup>

).

resulting in lower limits of detection.

314 Novel Nanomaterials - Synthesis and Applications

high affinity for thiol-containing compounds.

compounds are removed from the solution [35].

able problem for reliable application [36].

**3. Capillary electrophoresis for analysis of nanomaterials**

(0.01 mm<sup>2</sup>

Nowadays, an increasing number of researchers perform CE separations in short capillaries (units of centimeters) instead of microfluidic chips [48, 49]. In such capillaries, fast and efficient separations are carried out without complicated chip preparation requiring expensive facilities (e.g. clean rooms and lithography). Compared with microchip-based high-speed CE systems, short capillary-based high-speed CE systems take advantage of simple structure, easy fabrication, and low costs.

The disadvantage, however, is in lowered resolution connected with short separation length. This obstacle can be solved either by injection of extremely low sample volumes (picoliters) or by additional selectivity given by stationary of pseudo-stationary phases of various natures (e.g. micelles, nanoparticles, nanostructures, etc.), which significantly eliminate the adsorption of highly abundant proteins on the capillary wall [50–53]. Nanomaterials have been proven to be effective (pseudo)stationary phase due to their beneficial properties, such as large surface– to-volume ratio and easy modification. The most commonly used nanomaterials are carbon nanotubes [54]. However, other structures including nanoparticles [55, 56], nanofibres [57], and/or nanorods [58, 59] have been utilized for these purposes. On the other hand, surfacebinding method uses interaction between analyte with the surface of fixed nanostructures such as monoliths, nanopillars, immobilized nanoparticles, and/or other nanomaterials. All of these types have already been employed in coupling with in either capillary-based CE or microfluidic CE. Immobilized nanomaterials, either deposited on capillary wall as a thin layer coating or packed within the capillary, are commonly utilized as stationary phases for capillary electrochromatography. The (pseudo)stationary phases enable a broad range of functionalities offering a variety of interactions [60] (**Figure 2**).

**Figure 2.** Approaches for separation performance enhancement by nanomaterials. (A) Physically adsorbed opentubular phase, (B) covalently bound opentubular phase, (C) co-polymerized opentubular pahse, (D) full-filling sieving matrix, (E) mobile pseudo-stationary phase.

The efficiency of separation of two compounds is defined as resolution (*RS* ). It can be affected by alternating the electrophoretic mobility of the analytes and their electrophoretic mobilities. *RS* can be calculated according to the equation (1): *RS* <sup>=</sup> <sup>√</sup>*<sup>N</sup> μelA* <sup>−</sup> *<sup>μ</sup>* \_*elB*

$$\mathcal{R}\_{\mathbb{S}} = \sqrt{\mathcal{N} \frac{\mu\_{el\mathbb{A}} - \mu\_{el\mathbb{B}}}{4(\mu\_{av} + \mu\_{Eol})}} \tag{1}$$

Besides photoluminescence detection, chemiluminescence (CL) and electrochemiluminescence detection are also benefiting from properties of nanomaterials [70]. CL detection is based on measurement of electromagnetic radiation released after excitation of the electron by chemical reaction. The main advantages of CL are in the absence of undesired background signals, improved sensitivity, and wide linear dynamic range. Moreover, no excitation sources and/or optical filters are essential; therefore the instrumentation is simple, robust, and relatively low cost. In such instruments, metal-based nanoparticles can be used as catalysts, reductants, fluorophores, or acceptors of energy. Metal nanoparticles, such as gold, silver, platinum, semiconductors, and

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Electrochemical detection in CE can be carried out in three modes: potentiometric, amperometric, and conductometric. Potentiometric and conductometric detectors provide good sensitivity and on contrary, amperometric detection is selective and can be tuned to the analyte of interest. One of the main differences of this approach compared to the optical detection modes is that the electrochemical detection is mostly performed by off-column, end-capillary,

The use of nanomaterials for electrochemical detection covers a remarkably broad field. Due to their electrochemical properties, nanomaterials have been applied for electrochemical analysis of many analytes, comprising of nucleic acids [72–74], proteins [75, 76], secondary metabolites [77, 78], and/or metals [79]. The key roles delivered by nanoparticles include biomolecule immobilization, catalysis of electrochemical reactions, enhancement of electron transfer between electrode surfaces and proteins, biomolecule labeling, and even use as a reactant [80]. In addition to the relatively low financial demands of electrochemical detection in comparison to optical instrumentation, advantages such as the possibility of miniaturization and in-field applications are vital. Number of reviews covering this topic has been published. For example, Pumera and Escarpa [81] summarized the different approaches for constructing nanomaterialbased detectors for conventional CE and microchip electrophoresis and mostly focused on three main types of nanomaterials, that is, carbon nanotubes, nanoparticles, and nanorods, in various designs. The work by Garcia-Carmona focusses on highlighting the electrochemical detection enhancement in CE, chip electrophoresis, and paper-based microfluidic devices [82]. In our opinion, it is highly unlikely that nanomaterials will wholly substitute such well-established approaches as organic dyes for fluorescent labeling. However, nanomaterials offer new options for a broad range of applications. The electrochemical detection particularly benefits

There is no doubt that nanomaterials are extremely valuable tool for analytical applications enhancing highly the efficiency of extraction techniques, increasing significantly the resolution of separations, and improving greatly the capabilities of detection systems. There are a lot of key features of instruments used for clinical purposes including being easy to use and robust. In spite of the great advantages of capillary electrophoresis, robustness and repeatability of measurements belong to its weaknesses, which represent an obstacle for using of

magnetic types, provide beneficial properties for CL detection [71].

from use of nanomaterials that enable increasingly sensitive detection.

and therefore, in destructive arrangement.

**5. Conclusion**

where *N* is the number of theoretical plates, *μelA* and *μelB* are electrophoretic mobilities of the analytes, *μav* is the mean electrophoretic mobility of analyte *A* and *B*, and *μEOF* is mobility of electro-osmotic flow.

#### **4.2. Enhancement of detection**

Laser-induced fluorescence detection is (and most likely will be also in the future) the most sensitive detection technique among the optical detection modes following chemical separation. It has exceptionally low limits of detection (10−13 M) [61] and good detection selectivity in cases of sample analysis with rather complex matrices. Simultaneously, this selectivity could be perceived as a limitation because the majority of analytes lacks the desired fluorescent properties, and therefore, derivatization by some fluorescent label is needed.

Optical detection in association with nanomaterials is mainly connected with quantum dots due to their application as a fluorescent labels in laser-induced fluorescence detection [62–65]. An indirect laser-induced fluorescence mode of detection by means of CdTe quantum dots has been demonstrated and therefore determination of small organic acids in food with detection limits in the range of tenths of mg/L was enabled [64]. Moreover, determination of pesticide and antibiotic residues in vegetables [66, 67] and in foods [68] has been described. Chen and Fung presented laser-induced fluorescence detection using immobilized QDs to determine organophosphate pesticides (mevinphos, phosalone, methidathion, and diazinon) in vegetable samples [69]. Detection limits of the method were in the range of tens of μg/kg.

Besides photoluminescence detection, chemiluminescence (CL) and electrochemiluminescence detection are also benefiting from properties of nanomaterials [70]. CL detection is based on measurement of electromagnetic radiation released after excitation of the electron by chemical reaction. The main advantages of CL are in the absence of undesired background signals, improved sensitivity, and wide linear dynamic range. Moreover, no excitation sources and/or optical filters are essential; therefore the instrumentation is simple, robust, and relatively low cost. In such instruments, metal-based nanoparticles can be used as catalysts, reductants, fluorophores, or acceptors of energy. Metal nanoparticles, such as gold, silver, platinum, semiconductors, and magnetic types, provide beneficial properties for CL detection [71].

Electrochemical detection in CE can be carried out in three modes: potentiometric, amperometric, and conductometric. Potentiometric and conductometric detectors provide good sensitivity and on contrary, amperometric detection is selective and can be tuned to the analyte of interest. One of the main differences of this approach compared to the optical detection modes is that the electrochemical detection is mostly performed by off-column, end-capillary, and therefore, in destructive arrangement.

The use of nanomaterials for electrochemical detection covers a remarkably broad field. Due to their electrochemical properties, nanomaterials have been applied for electrochemical analysis of many analytes, comprising of nucleic acids [72–74], proteins [75, 76], secondary metabolites [77, 78], and/or metals [79]. The key roles delivered by nanoparticles include biomolecule immobilization, catalysis of electrochemical reactions, enhancement of electron transfer between electrode surfaces and proteins, biomolecule labeling, and even use as a reactant [80]. In addition to the relatively low financial demands of electrochemical detection in comparison to optical instrumentation, advantages such as the possibility of miniaturization and in-field applications are vital. Number of reviews covering this topic has been published. For example, Pumera and Escarpa [81] summarized the different approaches for constructing nanomaterialbased detectors for conventional CE and microchip electrophoresis and mostly focused on three main types of nanomaterials, that is, carbon nanotubes, nanoparticles, and nanorods, in various designs. The work by Garcia-Carmona focusses on highlighting the electrochemical detection enhancement in CE, chip electrophoresis, and paper-based microfluidic devices [82].

In our opinion, it is highly unlikely that nanomaterials will wholly substitute such well-established approaches as organic dyes for fluorescent labeling. However, nanomaterials offer new options for a broad range of applications. The electrochemical detection particularly benefits from use of nanomaterials that enable increasingly sensitive detection.

#### **5. Conclusion**

The efficiency of separation of two compounds is defined as resolution (*RS*

 can be calculated according to the equation (1): *RS* <sup>=</sup> <sup>√</sup>*<sup>N</sup> μelA* <sup>−</sup> *<sup>μ</sup>* \_*elB*

*RS*

electro-osmotic flow.

range of tens of μg/kg.

**4.2. Enhancement of detection**

(E) mobile pseudo-stationary phase.

316 Novel Nanomaterials - Synthesis and Applications

by alternating the electrophoretic mobility of the analytes and their electrophoretic mobilities.

**Figure 2.** Approaches for separation performance enhancement by nanomaterials. (A) Physically adsorbed opentubular phase, (B) covalently bound opentubular phase, (C) co-polymerized opentubular pahse, (D) full-filling sieving matrix,

where *N* is the number of theoretical plates, *μelA* and *μelB* are electrophoretic mobilities of the analytes, *μav* is the mean electrophoretic mobility of analyte *A* and *B*, and *μEOF* is mobility of

Laser-induced fluorescence detection is (and most likely will be also in the future) the most sensitive detection technique among the optical detection modes following chemical separation. It has exceptionally low limits of detection (10−13 M) [61] and good detection selectivity in cases of sample analysis with rather complex matrices. Simultaneously, this selectivity could be perceived as a limitation because the majority of analytes lacks the desired fluorescent

Optical detection in association with nanomaterials is mainly connected with quantum dots due to their application as a fluorescent labels in laser-induced fluorescence detection [62–65]. An indirect laser-induced fluorescence mode of detection by means of CdTe quantum dots has been demonstrated and therefore determination of small organic acids in food with detection limits in the range of tenths of mg/L was enabled [64]. Moreover, determination of pesticide and antibiotic residues in vegetables [66, 67] and in foods [68] has been described. Chen and Fung presented laser-induced fluorescence detection using immobilized QDs to determine organophosphate pesticides (mevinphos, phosalone, methidathion, and diazinon) in vegetable samples [69]. Detection limits of the method were in the

properties, and therefore, derivatization by some fluorescent label is needed.

). It can be affected

<sup>4</sup>(*μav* <sup>+</sup> *μEOF*) (1)

There is no doubt that nanomaterials are extremely valuable tool for analytical applications enhancing highly the efficiency of extraction techniques, increasing significantly the resolution of separations, and improving greatly the capabilities of detection systems. There are a lot of key features of instruments used for clinical purposes including being easy to use and robust. In spite of the great advantages of capillary electrophoresis, robustness and repeatability of measurements belong to its weaknesses, which represent an obstacle for using of capillary electrophoretic instrumentation in clinical practice with one exception represented by DNA sequencer. Utilization of nanomaterials in capillary electrophoresis is opening new perspective in the field of clinical usage because these advanced materials can lower detection limits on one side and enhance the separation effectiveness on the other side. Nevertheless, this is at the beginning and waiting for exploration.

**Acknowledgements**

**Author details**

Czech Republic

Czech Republic

**References**

Vojtech Adam1,2 and Marketa Vaculovicova1,2\*

Current Science. 2010;**99**:900-907

Electrophoresis. 1997;**18**:2482-2501

Electrophoresis. 2000;**21**:4179-4191

2004;**25**:4008-4031

ions. Electrophoresis. 2002;**23**:3884-3906

\*Address all correspondence to: marketa.ryvolova@seznam.cz

ing gold in gold-ruby glass. Nature. 2000;**407**:691-692

Financial support was provided by Grant agency of Czech Republic (GACR 16-23647Y) and project CEITEC 2020 (LQ1601) with financial support from the Ministry of Education, Youth

Capillary Electrophoresis in Nanotechnologies versus Nanotechnologies in Capillary…

http://dx.doi.org/10.5772/intechopen.72015

319

and Sports of the Czech Republic under the National Sustainability Programme II.

1 Department of Chemistry and Biochemistry, Mendel University in Brno, Brno,

2 Central European Institute of Technology, Brno University of Technology, Brno,

[1] Wagner FE, Haslbeck S, Stievano L, Calogero S, Pankhurst QA, Martinek P. Before strik-

[2] Yadugiri VT, Malhotra R. 'Plenty of room'—fifty years after the Feynman lecture.

[4] Macka M, Haddad PR. Determination of metal ions by capillary electrophoresis.

[5] Haddad PR, Doble P, Macka M. Developments in sample preparation and separation techniques for the determination of inorganic ions by ion chromatography and capillary

[6] Timerbaev AR, Shpigun OA. Recent progress in capillary electrophoresis of metal ions.

[7] Timerbaev AR. Recent advances and trends in capillary electrophoresis of inorganic

[8] Timerbaev AR. Capillary electrophoresis of inorganic ions: An update. Electrophoresis.

[9] DeBacker BL, Nagels LJ. Potentiometric detection for capillary electrophoresis: Determ-

electrophoresis. Journal of Chromatography A. 1999;**856**:145-177

ination of organic acids. Analytical Chemistry. 1996;**68**:4441-4445

[3] Whitesides GM. Nanoscience, nanotechnology, and chemistry. Small. 2005;**1**:172-179

From the CE point of view, NMs such as liposomes and dendrimes have abilities to improve the separation part of the CE analysis and QDs, on the other hand, they can significantly improve the detection part. However, there are several members of the nanomaterial family, which can improve both of those—carbon nanotubes and metal nanoparticles. At the same time, CE is an effective technique for NMs characterization, evaluation, and/or observation (**Figure 3**).

The symbiosis of CE and nanomaterials is beneficial not only for analytical chemists and material scientists, but also for biochemists and molecular biologists, because it leads to the development of new, more effective, and more sensitive methods.

The combination with the simplicity of miniaturization is opening the opportunities for portable and point-of-care applicable instrumentation suitable for personalized diagnostics. Moreover the separation power of electrophoretic analysis, even increased by nanomaterialbased stationary and pseudo-stationary phased in combination with advances in microfluidics, promises effective analyses of complex biological samples.

**Figure 3.** Summary of applications of nanomaterials in capillary electrophoresis.

## **Acknowledgements**

capillary electrophoretic instrumentation in clinical practice with one exception represented by DNA sequencer. Utilization of nanomaterials in capillary electrophoresis is opening new perspective in the field of clinical usage because these advanced materials can lower detection limits on one side and enhance the separation effectiveness on the other side. Nevertheless,

From the CE point of view, NMs such as liposomes and dendrimes have abilities to improve the separation part of the CE analysis and QDs, on the other hand, they can significantly improve the detection part. However, there are several members of the nanomaterial family, which can improve both of those—carbon nanotubes and metal nanoparticles. At the same time, CE is an effective technique for NMs characterization, evaluation, and/or observation (**Figure 3**).

The symbiosis of CE and nanomaterials is beneficial not only for analytical chemists and material scientists, but also for biochemists and molecular biologists, because it leads to the

The combination with the simplicity of miniaturization is opening the opportunities for portable and point-of-care applicable instrumentation suitable for personalized diagnostics. Moreover the separation power of electrophoretic analysis, even increased by nanomaterialbased stationary and pseudo-stationary phased in combination with advances in microfluid-

this is at the beginning and waiting for exploration.

318 Novel Nanomaterials - Synthesis and Applications

development of new, more effective, and more sensitive methods.

ics, promises effective analyses of complex biological samples.

**Figure 3.** Summary of applications of nanomaterials in capillary electrophoresis.

Financial support was provided by Grant agency of Czech Republic (GACR 16-23647Y) and project CEITEC 2020 (LQ1601) with financial support from the Ministry of Education, Youth and Sports of the Czech Republic under the National Sustainability Programme II.

### **Author details**

Vojtech Adam1,2 and Marketa Vaculovicova1,2\*

\*Address all correspondence to: marketa.ryvolova@seznam.cz

1 Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic

2 Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic

#### **References**


[10] Soga T, Ross GA. Simultaneous determination of inorganic anions, organic acids, amino acids and carbohydrates by capillary electrophoresis. Journal of Chromatography A. 1999;**837**:231-239

Vech C, Wang G, Wetter J, Williams S, Williams M, Windsor S, Winn-Deen E, Wolfe K, Zaveri J, Zaveri K, Abril JF, Guigo R, Campbell MJ, Sjolander KV, Karlak B, Kejariwal A, Mi HY, Lazareva B, Hatton T, Narechania A, Diemer K, Muruganujan A, Guo N, Sato S, Bafna V, Istrail S, Lippert R, Schwartz R, Walenz B, Yooseph S, Allen D, Basu A, Baxendale J, lick L, Caminha M, Carnes-Stine J, Caulk P, Chiang YH, Coyne M, Dahlke C, Mays AD, Dombroski M, Donnelly M, Ely D, Esparham S, Fosler C, Gire H, Glanowski S, Glasser K, Glodek A, Gorokhov M, Graham K, Gropman B, Harris M, Heil J, Henderson S, Hoover J, Jennings D, Jordan C, Jordan J, Kasha J, Kagan L, Kraft C, Levitsky A, Lewis M, Liu XJ, Lopez J, Ma D, Majoros W, McDaniel J, Murphy S, Newman M, Nguyen T, Nguyen N, Nodell M, Pan S, Peck J, Peterson M, Rowe W, Sanders R, Scott J, Simpson M, Smith T, Sprague A, Stockwell T, Turner R, Venter E, Wang M, Wen MY, Wu D, Wu M, Xia A,

Capillary Electrophoresis in Nanotechnologies versus Nanotechnologies in Capillary…

http://dx.doi.org/10.5772/intechopen.72015

321

Zandieh A, Zhu XH. The sequence of the human genome. Science. 2001;**291**:1304

[19] Manz A, Graber N, Widmer HM. Miniaturizes total chemical-analysis systems—A novel concept for chemical sensing. Sensors and Actuators B—Chemical. 1990;**1**:244-248

[20] Dolnik V, Liu SR, Jovanovich S. Capillary electrophoresis on microchip. Electrophoresis.

[21] Dolnik V, Liu SR. Applications of capillary electrophoresis on microchip. Journal of

[22] Li SFY, Kricka LJ. Clinical analysis by microchip capillary electrophoresis. Clinical

[23] Breadmore MC. Capillary and microchip electrophoresis: Challenging the common con-

[24] Osbourn DM, Weiss DJ, Lunte CE. On-line preconcentration methods for capillary elec-

[25] Shihabi ZK. Transient pseudo-isotachophoresis for sample concentration in capillary

[26] Timerbaev AR, Hirokawa T. Recent advances of transient isotachophoresis-capillary electrophoresis in the analysis of small ions from high-conductivity matrices. Electrophoresis.

[27] Beckers JL, Bocek P. Sample stacking in capillary zone electrophoresis: Principles,

[28] Quirino JP, Terabe S. Sample stacking of cationic and anionic analytes in capillary elec-

[29] Shihabi ZK. Stacking in capillary zone electrophoresis. Journal of Chromatography A.

[30] Quirino JP, Terabe S. Approaching a million-fold sensitivity increase in capillary electrophoresis with direct ultraviolet detection: Cation-selective exhaustive injection and

2000;**21**:41-54

2006;**27**:323-340

2000;**902**:107-117

Separation Science. 2005;**28**:1994-2009

ceptions. Journal of Chromatography A. 2012;**1221**:42-55

trophoresis. Electrophoresis. 2000;**21**:2768-2779

electrophoresis. Electrophoresis. 2002;**23**:1612-1617

advantages and limitations. Electrophoresis. 2000;**21**:2747-2767

trophoresis. Journal of Chromatography A. 2000;**902**:119-135

sweeping. Analytical Chemistry. 2000;**72**:1023-1030

Chemistry. 2006;**52**:37-45


Vech C, Wang G, Wetter J, Williams S, Williams M, Windsor S, Winn-Deen E, Wolfe K, Zaveri J, Zaveri K, Abril JF, Guigo R, Campbell MJ, Sjolander KV, Karlak B, Kejariwal A, Mi HY, Lazareva B, Hatton T, Narechania A, Diemer K, Muruganujan A, Guo N, Sato S, Bafna V, Istrail S, Lippert R, Schwartz R, Walenz B, Yooseph S, Allen D, Basu A, Baxendale J, lick L, Caminha M, Carnes-Stine J, Caulk P, Chiang YH, Coyne M, Dahlke C, Mays AD, Dombroski M, Donnelly M, Ely D, Esparham S, Fosler C, Gire H, Glanowski S, Glasser K, Glodek A, Gorokhov M, Graham K, Gropman B, Harris M, Heil J, Henderson S, Hoover J, Jennings D, Jordan C, Jordan J, Kasha J, Kagan L, Kraft C, Levitsky A, Lewis M, Liu XJ, Lopez J, Ma D, Majoros W, McDaniel J, Murphy S, Newman M, Nguyen T, Nguyen N, Nodell M, Pan S, Peck J, Peterson M, Rowe W, Sanders R, Scott J, Simpson M, Smith T, Sprague A, Stockwell T, Turner R, Venter E, Wang M, Wen MY, Wu D, Wu M, Xia A, Zandieh A, Zhu XH. The sequence of the human genome. Science. 2001;**291**:1304

[10] Soga T, Ross GA. Simultaneous determination of inorganic anions, organic acids, amino acids and carbohydrates by capillary electrophoresis. Journal of Chromatography A.

[11] Soga T, Imaizumi M. Capillary electrophoresis method for the analysis of inorganic anions, organic acids, amino acids, nucleotides, carbohydrates and other anionic com-

[12] Huang YF, Huang CC, CC H, Chang HT. Capillary electrophoresis-based separation

[13] Haselberg R, de Jong GJ, Somsen GW. Capillary electrophoresis-mass spectrometry for the analysis of intact proteins. Journal of Chromatography A. 2007;**1159**:81-109

[14] Dolnik V. Capillary electrophoresis of proteins 2005-2007. Electrophoresis. 2008;**29**:

[15] Heller C. Principles of DNA separation with capillary electrophoresis. Electrophoresis.

[16] Righetti PG, Gelfi C, D'Acunto MR. Recent progress in DNA analysis by capillary elec-

[17] Kleparnik K, Bocek P. DNA diagnostics by capillary electrophoresis. Chemical Reviews.

[18] Venter JC, Adams MD, Myers EW, Li PW, Mural RJ, Sutton GG, Smith HO, Yandell M, Evans CA, Holt RA, Gocayne JD, Amanatides P, Ballew RM, Huson DH, Wortman JR, Zhang Q, Kodira CD, Zheng XQH, Chen L, Skupski M, Subramanian G, Thomas PD, Zhang JH, Miklos GLG, Nelson C, Broder S, Clark AG, Nadeau C, McKusick VA, Zinder N, Levine AJ, Roberts RJ, Simon M, Slayman C, Hunkapiller M, Bolanos R, Delcher A, Dew I, Fasulo D, Flanigan M, Florea L, Halpern A, Hannenhalli S, Kravitz S, Levy S, Mobarry C, Reinert K, Remington K, Abu-Threideh J, Beasley E, Biddick K, Bonazzi V, Brandon R, Cargill M, Chandramouliswaran I, Charlab R, Chaturvedi K, Deng ZM, Di Francesco V, Dunn P, Eilbeck K, Evangelista C, Gabrielian AE, Gan W, Ge WM, Gong FC, Gu ZP, Guan P, Heiman TJ, Higgins ME, Ji RR, Ke ZX, Ketchum KA, Lai ZW, Lei YD, Li ZY, Li JY, Liang Y, Lin XY, Lu F, Merkulov GV, Milshina N, Moore HM, Naik AK, Narayan VA, Neelam B, Nusskern D, Rusch DB, Salzberg S, Shao W, Shue BX, Sun JT, Wang ZY, Wang AH, Wang X, Wang J, Wei MH, Wides R, Xiao CL, Yan CH, Yao A, Ye J, Zhan M, Zhang WQ, Zhang HY, Zhao Q, Zheng LS, Zhong F, Zhong WY, Zhu SPC, Zhao SY, Gilbert D, Baumhueter S, Spier G, Carter C, Cravchik A, Woodage T, Ali F, An HJ, Awe A, Baldwin D, Baden H, Barnstead M, Barrow I, Beeson K, Busam D, Carver A, Center A, Cheng ML, Curry L, Danaher S, Davenport L, Desilets R, Dietz S, Dodson K, Doup L, Ferriera S, Garg N, Gluecksmann A, Hart B, Haynes J, Haynes C, Heiner C, Hladun S, Hostin D, Houck J, Howland T, Ibegwam C, Johnson J, Kalush F, Kline L, Koduru S, Love A, Mann F, May D, McCawley S, McIntosh T, McMullen I, Moy M, Moy L, Murphy B, Nelson K, Pfannkoch C, Pratts E, Puri V, Qureshi H, Reardon M, Rodriguez R, Rogers YH, Romblad D, Ruhfel B, Scott R, Sitter C, Smallwood M, Stewart E, Strong R, Suh E, Thomas R, Tint NN, Tse S,

techniques for the analysis of proteins. Electrophoresis. 2006;**27**:3503-3522

1999;**837**:231-239

320 Novel Nanomaterials - Synthesis and Applications

143-156

2001;**22**:629-643

2007;**107**:5279-5317

pounds. Electrophoresis. 2001;**22**:3418-3425

trophoresis. Electrophoresis. 2002;**23**:1361-1374


[31] Quirino JP, Kim JB, Terabe S. Sweeping: Concentration mechanism and applications to high-sensitivity analysis in capillary electrophoresis. Journal of Chromatography A. 2002;**965**:357-373

[46] Sang FM, Huang XY, Ren JC. Characterization and separation of semiconductor quantum dots and their conjugates by capillary electrophoresis. Electrophoresis. 2014;**35**:793-803

Capillary Electrophoresis in Nanotechnologies versus Nanotechnologies in Capillary…

http://dx.doi.org/10.5772/intechopen.72015

323

[47] Stanisavljevic M, Vaculovicova M, Kizek R, Adam V. Capillary electrophoresis of quan-

[48] Lin QH, Cheng YQ, Dong YN, Zhu Y, Pan JZ, Fang Q. High-speed separation of proteins by sodium dodecyl sulfate-capillary gel electrophoresis with partial translational spon-

[49] Wang W, Ma LH, Yao FZ, Lin XL, Xu KX. High-speed separation and detection of amino acids in laver using a short capillary electrophoresis system. Electrophoresis.

[50] Terabe S. Capillary separation: Micellar electrokinetic chromatography. In: Annual Review of Analytical Chemistry. Palo Alto: Annual Reviews; 2009. pp. 99-120

[51] Duan AH, Xie SM, Yuan LM. Nanoparticles as stationary and pseudo-stationary phases in chromatographic and electrochromatographic separations. Trac—Trends in

[52] Gonzalez-Curbelo MA, Varela-Martinez DA, Socas-Rodriguez B, Hernandez-Borges J. Recent applications of nanomaterials in capillary electrophoresis. Electrophoresis.

[53] Hajba L, Guttman A. Recent advances in column coatings for capillary electrophoresis of

[54] Ravelo-Perez LM, Herrera-Herrera AV, Hernandez-Borges J, Rodriguez-Delgado MA. Carbon nanotubes: Solid-phase extraction. Journal of Chromatography A. 2010;**1217**:

[55] Peng Y, Xie Y, Luo J, Nie L, Chen Y, Chen LN, SH D, Zhang ZP. Molecularly imprinted polymer layer-coated silica nanoparticles toward dispersive solid-phase extraction of trace sulfonylurea herbicides from soil and crop samples. Analytica Chimica Acta.

[56] Guihen E. Recent highlights in electro-driven separations-selected applications of alkylthiol gold nanoparticles in capillary electrophoresis and capillary electro-chromatogra-

[57] Chigome S, Darko G, Torto N. Electrospun nanofibers as sorbent material for solid phase

[58] Wang D, Zhang ZM, Luo L, Li TM, Zhang L, Chen GN. ZnO nanorod array solid phase micro-extraction fiber coating: Fabrication and extraction capability. Nanotechnology.

[59] Wang D, Wang QT, Zhang ZM, Chen GN. ZnO nanorod array polydimethylsiloxane composite solid phase micro-extraction fiber coating: Fabrication and extraction capability.

tum dots: Minireview. Electrophoresis. 2014;**35**:1929-1937

taneous sample injection. Electrophoresis. 2011;**32**:2898-2903

proteins. Trac—Trends in Analytical Chemistry. 2017;**90**:38-44

2015;**36**:335-340

2017;**38**:2431-2446

2618-2641

2009;**20**

2010;**674**:190-200

Analytical Chemistry. 2011;**30**:484-491

phy. Electrophoresis. 2017;**38**:2184-2192

The Analyst. 2012;**137**:476-480

extraction. The Analyst. 2011;**136**:2879-2889


[46] Sang FM, Huang XY, Ren JC. Characterization and separation of semiconductor quantum dots and their conjugates by capillary electrophoresis. Electrophoresis. 2014;**35**:793-803

[31] Quirino JP, Kim JB, Terabe S. Sweeping: Concentration mechanism and applications to high-sensitivity analysis in capillary electrophoresis. Journal of Chromatography A.

[32] Aranas AT, Guidote AM, Quirino JP. Sweeping and new on-line sample preconcentration techniques in capillary electrophoresis. Analytical and Bioanalytical Chemistry.

[33] Britz-McKibbin P, Chen DDY. Selective focusing of catecholamines and weakly acidic compounds by capillary electrophoresis using a dynamic pH junction. Analytical

[34] Kazarian AA, Hilder EF, Breadmore MC. Online sample pre-concentration via dynamic pH junction in capillary and microchip electrophoresis. Journal of Separation Science.

[35] Adam V, Vaculovicova M. Nanomaterials for sample pretreatment prior to capillary

[36] Adam V, Vaculovicova M. Capillary electrophoresis and nanomaterials—Part I: Capillary

[37] Rodriguez MA, Armstrong DW. Separation and analysis of colloidal/nano-particles including microorganisms by capillary electrophoresis: A fundamental review. Journal of Chromatography B-Analytical Technologies in the Biomedical and Life Sciences.

[38] Surugau N, Urban PL. Electrophoretic methods for separation of nanoparticles. Journal

[39] Pyell U. Characterization of nanoparticles by capillary electromigration separation tech-

[40] Lopez-Lorente AI, Simonet BM, Valcarcel M. Electrophoretic methods for the analysis of

[41] Aleksenko SS, Matczuk M, Timerbaev AR. Characterization of interactions of metal-containing nanoparticles with biomolecules by CE: An update (2012-2016). Electrophoresis.

[42] Salafi T, Zeming KK, Zhang Y. Advancements in microfluidics for nanoparticle separa-

[43] Shi XY, Banyai I, Lesniak WG, Islam MT, Orszagh I, Balogh P, Baker JR, Balogh LP. Capillary electrophoresis of polycationic poly(amidoamine) dendrimers. Electropho-

[44] Liu FK. Analysis and applications of nanoparticles in the separation sciences: A case of

[45] CS W, Liu FK, Ko FH. Potential role of gold nanoparticles for improved analytical methods: An introduction to characterizations and applications. Analytical and Bioanalytical

gold nanoparticles. Journal of Chromatography A. 2009;**1216**:9034-9047

nanoparticles. Trac—Trends in Analytical Chemistry. 2011;**30**:58-71

electrophoretic analysis. The Analyst. 2017;**142**:849-857

of Separation Science. 2009;**32**:1889-1906

niques. Electrophoresis. 2010;**31**:814-831

tion. Lab on a Chip. 2017;**17**:11-33

electrophoresis of nanomaterials. Electrophoresis. 2017:1-16

2002;**965**:357-373

322 Novel Nanomaterials - Synthesis and Applications

2009;**394**:175-185

2011;**34**:2800-2821

2004;**800**:7-25

2017;**38**:1661-1668

resis. 2005;**26**:2949-2959

Chemistry. 2011;**399**:103-118

Chemistry. 2000;**72**:1242-1252


[60] Adam V, Vaculovicova M. CE and nanomaterials—Part II: Nanomaterials in CE. Electrophoresis. 2017:1-26

[74] Liu XG, Cheng ZQ, Fan H, Ai SY, Han RX. Electrochemical detection of avian influenza virus H5N1 gene sequence using a DNA aptamer immobilized onto a hybrid nanomate-

Capillary Electrophoresis in Nanotechnologies versus Nanotechnologies in Capillary…

http://dx.doi.org/10.5772/intechopen.72015

325

[75] Rusling JF, Sotzing G, Papadimitrakopoulosa F. Designing nanomaterial-enhanced electrochemical immunosensors for cancer biomarker proteins. Bioelectrochemistry.

[76] Rusling JF. Nanomaterials-based electrochemical immunosensors for proteins. Chemical

[77] de Andres F, Zougagh M, Castaneda G, Rios A. Determination of zearalenone and its metabolites in urine samples by liquid chromatography with electrochemical detection using a carbon nanotube-modified electrode. Journal of Chromatography A. 2008;**1212**:

[78] Songa EA, Waryo T, Jahed N, Baker PGL, Kgarebe BV, Iwuoha EI. Electrochemical Nanobiosensor for glyphosate herbicide and its metabolite. Electroanalysis. 2009;**21**:

[79] Aragay G, Merkoci A. Nanomaterials application in electrochemical detection of heavy

[80] Luo XL, Morrin A, Killard AJ, Smyth MR. Application of nanoparticles in electrochemi-

[81] Pumera M, Escarpa A. Nanomaterials as electrochemical detectors in microfluidics and CE: Fundamentals, designs, and applications. Electrophoresis. 2009;**30**:3315-3323 [82] Garcia-Carmona L, Martin A, Sierra T, Gonzalez MC, Escarpa A. Electrochemical detectors based on carbon and metallic nanostructures in capillary and microchip electropho-

rial-modified electrode. Electrochimica Acta. 2011;**56**:6266-6270

2009;**76**:189-194

54-60

671-674

Record. 2012;**12**:164-176

metals. Electrochimica Acta. 2012;**84**:49-61

resis. Electrophoresis. 2017;**38**:80-94

cal sensors and biosensors. Electroanalysis. 2006;**18**:319-326


[74] Liu XG, Cheng ZQ, Fan H, Ai SY, Han RX. Electrochemical detection of avian influenza virus H5N1 gene sequence using a DNA aptamer immobilized onto a hybrid nanomaterial-modified electrode. Electrochimica Acta. 2011;**56**:6266-6270

[60] Adam V, Vaculovicova M. CE and nanomaterials—Part II: Nanomaterials in CE. Electro-

[61] Swinney K, Bornhop DJ. Detection in capillary electrophoresis. Electrophoresis. 2000;

[62] Bai Y, FY D, Yang YY, Liu HW. In-capillary non-covalent labeling and determination of tomato systemin with quantum dots in capillary electrophoresis with laser-induced

[63] Chen QD, Zhao WF, Fung YS. Determination of acrylamide in potato crisps by capillary electrophoresis with quantum dot-mediated LIF detection. Electrophoresis.

[64] Guo DS, Chen GH, Tong MZ, CQ W, Fang R, Yi LX. Determination of five preservatives in food by capillary electrophoresis with quantum dot indirect laser induced fluores-

[65] Qiu L, Bi YH, Wang CL, Li JY, Guo PL, Li JC, He WJ, Wang JH, Jiang PJ. Protein a detection based on quantum dots-antibody bioprobe using fluorescence coupled capillary

[66] Chen GH, Sun J, Dai YJ, Dong M. Determination of nicotinyl pesticide residues in vegetables by micellar electrokinetic capillary chromatography with quantum dot indirect

[67] Tang TT, Deng JJ, Zhang M, Shi GY, Zhou TS. Quantum dot-DNA aptamer conjugates coupled with capillary electrophoresis: A universal strategy for ratiometric detection of

[68] Meng HL, Chen GH, Guo X, Chen P, Cai QH, Tian YF. Determination of five quinolone antibiotic residues in foods by micellar electrokinetic capillary chromatography with quantum dot indirect laser-induced fluorescence. Analytical and Bioanalytical

[69] Chen QD, Fung YS. Capillary electrophoresis with immobilized quantum dot fluorescence detection for rapid determination of organophosphorus pesticides in vegetables.

[70] Yao J, Li L, Li PF, Yang M.Quantum dots: From fluorescence to chemiluminescence, bioluminescence, electrochemiluminescence, and electrochemistry. Nanoscale. 2017;**9**:13364-13383

[71] Giokas DL, Vlessidis AG, Tsogas GZ, Evmiridis NP. Nanoparticle-assisted chemiluminescence and its applications in analytical chemistry. Trac—Trends in Analytical

[72] Erdem A. Nanomaterial-based electrochemical DNA sensing strategies. Talanta. 2007;

[73] Mao X, Liu GD. Nanomaterial based electrochemical DNA biosensors and bioassays.

electrophoresis. International Journal of Molecular Sciences. 2014;**15**:1804-1811

fluorescence detection. Journal of Separation Science. 2011;**34**:2893-2900

cence. Chinese Journal of Analytical Chemistry. 2012;**40**:1379-1384

laser-induced fluorescence. Electrophoresis. 2012;**33**:2192-2196

organophosphorus pesticides. Talanta. 2016;**146**:55-61

Journal of Biomedical Nanotechnology. 2008;**4**:419-431

Chemistry. 2014;**406**:3201-3208

Electrophoresis. 2010;**31**:3107-3114

Chemistry. 2010;**29**:1113-1126

**74**:318-325

phoresis. 2017:1-26

324 Novel Nanomaterials - Synthesis and Applications

2011;**32**:1252-1257

**21**:1239-1250


**Chapter 18**

**Provisional chapter**

**Nanofluids as Novel Alternative Smart Fluids for**

**Nanofluids as Novel Alternative Smart Fluids for** 

DOI: 10.5772/intechopen.72267

This chapter presents an account of two metal oxide nanoparticles (zirconium and nickel oxide) on basis of their structure, morphology, crystallinity phases, and their wetting effect on solid-liquid interface. As a preliminary step to sound understanding of process mechanisms; wettability, nanoparticles, and their relations thereof were scrutinized. To investigate the nanofluids wetting inclinations, complex mixtures of the nanoparticles

wetting agents tested via contact angle measurement. The result shows that the nanoparticles exhibit different structural and morphological features and capable of addressing reservoir wettability challenges owing to favorable adsorption behavior on the surface of the calcite which facilitated the wetting changes quantified by contact angle. We believe this study will significantly impact the understanding of wetting at solid-liquid interface

**Keywords:** nanoparticles, calcite, zirconium oxide, nickel oxide, carbonate, wettability,

In the past half century, industrial processes in general have experienced a transition in material applications owing to a shift from conventional bulk materials toward nanoscale materials. This has driven innovative applications in wide-ranging areas of science and technology globally, thus yielding a proliferating interest and investment in nanoscience and nanotechnology fields. The increase possibilities for the manipulation of matter in nanometer-scale have primarily led to this growth with nanomaterials at the leading edge of this fast-developing field. The

/NaCl; NiO/NaCl) were formulated and their technical feasibility as

© 2016 The Author(s). Licensee InTech. 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,

© 2018 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.

and reproduction in any medium, provided the original work is properly cited.

**Reservoir Wettability Alteration**

**Reservoir Wettability Alteration**

Lezorgia Nekabari Nwidee, Ahmed Barifcani, Mohammad Sarmadivaleh and Stefan Iglauer

Lezorgia Nekabari Nwidee, Ahmed Barifcani, Mohammad Sarmadivaleh and Stefan Iglauer

Additional information is available at the end of the chapter

which is crucial for recovery process optimization.

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72267

**Abstract**

EOR

and NaCl brine (ZrO2

**1. Overview of nanomaterials**

**Provisional chapter**

#### **Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration Reservoir Wettability Alteration**

**Nanofluids as Novel Alternative Smart Fluids for** 

DOI: 10.5772/intechopen.72267

Lezorgia Nekabari Nwidee, Ahmed Barifcani, Mohammad Sarmadivaleh and Stefan Iglauer Mohammad Sarmadivaleh and Stefan Iglauer Additional information is available at the end of the chapter

Lezorgia Nekabari Nwidee, Ahmed Barifcani,

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72267

#### **Abstract**

This chapter presents an account of two metal oxide nanoparticles (zirconium and nickel oxide) on basis of their structure, morphology, crystallinity phases, and their wetting effect on solid-liquid interface. As a preliminary step to sound understanding of process mechanisms; wettability, nanoparticles, and their relations thereof were scrutinized. To investigate the nanofluids wetting inclinations, complex mixtures of the nanoparticles and NaCl brine (ZrO2 /NaCl; NiO/NaCl) were formulated and their technical feasibility as wetting agents tested via contact angle measurement. The result shows that the nanoparticles exhibit different structural and morphological features and capable of addressing reservoir wettability challenges owing to favorable adsorption behavior on the surface of the calcite which facilitated the wetting changes quantified by contact angle. We believe this study will significantly impact the understanding of wetting at solid-liquid interface which is crucial for recovery process optimization.

**Keywords:** nanoparticles, calcite, zirconium oxide, nickel oxide, carbonate, wettability, EOR

#### **1. Overview of nanomaterials**

In the past half century, industrial processes in general have experienced a transition in material applications owing to a shift from conventional bulk materials toward nanoscale materials. This has driven innovative applications in wide-ranging areas of science and technology globally, thus yielding a proliferating interest and investment in nanoscience and nanotechnology fields. The increase possibilities for the manipulation of matter in nanometer-scale have primarily led to this growth with nanomaterials at the leading edge of this fast-developing field. The

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. © 2018 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.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

potentials for direct control of systems at the same scale as nature such as DNA, cells, mitochondria and even reservoir rock pores can yield effective approaches in a wide variety of industrial processes such as the production of chemicals, materials, and energy [1]. Although nanomaterial appears to be a recent development owing to the current tremendous research growth and diverse applications, this material is not completely new as it has a rather shocking protracted history. The knowledge of the materials commenced as early as the 1950's by Richard Feynman who proposed that fabrications of materials and devices can be performed at atomic scales. Then in the 1980s, the term nanotechnology became even popular as established by Drexler Eric K. The current applications of these materials are not an exclusive result of modern research or laboratory synthesis, or even circumscribed to man-made materials. These materials have long been in existence with traceable applications in the old days. For instance, natural asbestos nanofibers and metal nanoparticles were used several decades ago for the control reinforcement of ceramic matrix and as color pigments in glass and luster technology respectively [2, 3].

or manipulated for the creation of larger scale materials to facilitate innovative applications. The material allow for clear-cut design and manipulation of atoms and molecules and its industrial applications are cost-effective and efficient [11, 12]. Nanoparticle cut across diverse fields of science and engineering and shows great potentials as effective approach for novel applications with high technological prospects and environmental friendliness. A recent drift

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

329

Nanoparticles are nano-sized structures with dimensions in the range of 1 to 100 nm. These materials exhibit unique properties with better potentials than bulk materials. Nanoparticles application enables the creation of new composites with unique properties which allows for innovative technological advancements. Unarguably, the effectiveness of this material cut across diverse industries such as energy, manufacturing, medicine, electronics, oil and gas industries etc., however, the understanding of the material is still very limited in EOR pro-

Nanoparticles are categorized as magnetic (iron, cobalt etc. and the oxides) [13–16], metallic (gold, silver, copper, and Platinum) [17, 18] or metal oxides (oxides of aluminum, zinc, silicon, magnesium, zirconium, cerium, titanium) [8, 19–23]. Among these categories, the metal oxides are the most commonly used nanoparticles in EOR [24–28] as the material offers special unique structures, compositions, physical, and chemical properties. These materials display efficient thermal conductivity effect [8], great stability [19] and excellent saline-alkaline tolerance [23]. However, its effectiveness depends greatly on the preparation methods, dispersant and subsequent applicability. Generally, nanoparticles can be prepared via chemical, biological or physical methods, although the preparation method is mainly based on the nature of the

Nanofluids are colloidal suspensions of solid nanoparticles or nanofibers. These solid-liquid composite materials are typically two-phase systems, consisting of a carrier medium and solid phase. The carrier liquids are often water, polymer solution, oil, ethylene glycol and sodium chloride brine. The solid phases are nanoparticles of chemically stable metals and oxides usually within the range of 1-100 nm [30–39]. Nanofluid has continuously attracted great attention for various processes owing to its great thermal properties at low volume fractions of less than 1%. To achieve the same functionality with conventional suspensions of well-dispersed particles, high concentrations that are greater than 10% of particles is often a requirement. Such high concentrations increase the issues of rheology and stability which has remained a deterrent to the extensive use of conventional slurries as heat transfer fluids [35]. Nanofluid production can be achieved via chemical or physical synthesis. The chemical synthesis involves the use of methods such as thermal spraying, chemical vapor deposition, spray pyrolysis, chemical precipitation, or micro-emulsions. Whereas, the physical synthesis involves inert-gas-condensation technique and mechanical grinding approach. During its production, a one-step or two-step approach can be adopted. The one-step approach allows for the production of nanoparticle and its dispersion

in its application is its usage for resolving reservoir engineering challenges.

material and associated chemical reactions [29], and the applications thereof.

**1.1. Nanoparticles**

cesses especially in wetting evaluations.

**1.2. Nanofluid production and stability control**

Ever since, novel studies of nanoscale fundamentals and principles, design, characterization, production, and application of these materials [4–6] have evolved and remained intriguing and ground-breaking. Since 2000, the nanotechnology industry has experienced a growing trend and the funding of nanotechnology research has also been on the rise (**Figure 1**). For example; in 2013, the global market for nanotechnology was estimated at \$22.9 billion, by 2014, the estimate had grown to about \$26 billion with a further projected growth of about \$64.2 billion by 2019 [7]. This innovative development involves the nanometer (nm) length scale manipulations of the structure of matter, where a nanometer represents a billionth of a meter, a distance that is equivalent to 2–20 atoms positioned next to one another. Nanomaterial has increasingly gained attention for a variety of processes such as electronic cooling and space applications, transportation, biomedicine, cooling of high-power laser diodes and submarines, and heating of buildings [8, 9]. Its wide applicability also extends to the field of environmental protection. This material exhibits great potentials as pollution reduction agent and improves the quality of air, water, and soil [10] and it is also currently being used as novel tools for oil and gas operations. Nanomaterials especially nanoparticles can be used alone

**Figure 1.** Worldwide nanotechnology research and funding by year [7].

or manipulated for the creation of larger scale materials to facilitate innovative applications. The material allow for clear-cut design and manipulation of atoms and molecules and its industrial applications are cost-effective and efficient [11, 12]. Nanoparticle cut across diverse fields of science and engineering and shows great potentials as effective approach for novel applications with high technological prospects and environmental friendliness. A recent drift in its application is its usage for resolving reservoir engineering challenges.

#### **1.1. Nanoparticles**

potentials for direct control of systems at the same scale as nature such as DNA, cells, mitochondria and even reservoir rock pores can yield effective approaches in a wide variety of industrial processes such as the production of chemicals, materials, and energy [1]. Although nanomaterial appears to be a recent development owing to the current tremendous research growth and diverse applications, this material is not completely new as it has a rather shocking protracted history. The knowledge of the materials commenced as early as the 1950's by Richard Feynman who proposed that fabrications of materials and devices can be performed at atomic scales. Then in the 1980s, the term nanotechnology became even popular as established by Drexler Eric K. The current applications of these materials are not an exclusive result of modern research or laboratory synthesis, or even circumscribed to man-made materials. These materials have long been in existence with traceable applications in the old days. For instance, natural asbestos nanofibers and metal nanoparticles were used several decades ago for the control reinforcement of ceramic matrix and as color pigments in glass and luster technology respectively [2, 3]. Ever since, novel studies of nanoscale fundamentals and principles, design, characterization, production, and application of these materials [4–6] have evolved and remained intriguing and ground-breaking. Since 2000, the nanotechnology industry has experienced a growing trend and the funding of nanotechnology research has also been on the rise (**Figure 1**). For example; in 2013, the global market for nanotechnology was estimated at \$22.9 billion, by 2014, the estimate had grown to about \$26 billion with a further projected growth of about \$64.2 billion by 2019 [7]. This innovative development involves the nanometer (nm) length scale manipulations of the structure of matter, where a nanometer represents a billionth of a meter, a distance that is equivalent to 2–20 atoms positioned next to one another. Nanomaterial has increasingly gained attention for a variety of processes such as electronic cooling and space applications, transportation, biomedicine, cooling of high-power laser diodes and submarines, and heating of buildings [8, 9]. Its wide applicability also extends to the field of environmental protection. This material exhibits great potentials as pollution reduction agent and improves the quality of air, water, and soil [10] and it is also currently being used as novel tools for oil and gas operations. Nanomaterials especially nanoparticles can be used alone

328 Novel Nanomaterials - Synthesis and Applications

**Figure 1.** Worldwide nanotechnology research and funding by year [7].

Nanoparticles are nano-sized structures with dimensions in the range of 1 to 100 nm. These materials exhibit unique properties with better potentials than bulk materials. Nanoparticles application enables the creation of new composites with unique properties which allows for innovative technological advancements. Unarguably, the effectiveness of this material cut across diverse industries such as energy, manufacturing, medicine, electronics, oil and gas industries etc., however, the understanding of the material is still very limited in EOR processes especially in wetting evaluations.

Nanoparticles are categorized as magnetic (iron, cobalt etc. and the oxides) [13–16], metallic (gold, silver, copper, and Platinum) [17, 18] or metal oxides (oxides of aluminum, zinc, silicon, magnesium, zirconium, cerium, titanium) [8, 19–23]. Among these categories, the metal oxides are the most commonly used nanoparticles in EOR [24–28] as the material offers special unique structures, compositions, physical, and chemical properties. These materials display efficient thermal conductivity effect [8], great stability [19] and excellent saline-alkaline tolerance [23]. However, its effectiveness depends greatly on the preparation methods, dispersant and subsequent applicability. Generally, nanoparticles can be prepared via chemical, biological or physical methods, although the preparation method is mainly based on the nature of the material and associated chemical reactions [29], and the applications thereof.

#### **1.2. Nanofluid production and stability control**

Nanofluids are colloidal suspensions of solid nanoparticles or nanofibers. These solid-liquid composite materials are typically two-phase systems, consisting of a carrier medium and solid phase. The carrier liquids are often water, polymer solution, oil, ethylene glycol and sodium chloride brine. The solid phases are nanoparticles of chemically stable metals and oxides usually within the range of 1-100 nm [30–39]. Nanofluid has continuously attracted great attention for various processes owing to its great thermal properties at low volume fractions of less than 1%. To achieve the same functionality with conventional suspensions of well-dispersed particles, high concentrations that are greater than 10% of particles is often a requirement. Such high concentrations increase the issues of rheology and stability which has remained a deterrent to the extensive use of conventional slurries as heat transfer fluids [35]. Nanofluid production can be achieved via chemical or physical synthesis. The chemical synthesis involves the use of methods such as thermal spraying, chemical vapor deposition, spray pyrolysis, chemical precipitation, or micro-emulsions. Whereas, the physical synthesis involves inert-gas-condensation technique and mechanical grinding approach. During its production, a one-step or two-step approach can be adopted. The one-step approach allows for the production of nanoparticle and its dispersion in a fluid in a single combined process, which is suitable for nanofluids with high-conductivity metals contents. Whereas with the two-step method, production process is performed in two separate steps, firstly, the nanoparticle is produced, and then the produced nanoparticle is dispersed in a fluid – this is considered an effective strategy for commercial use [8, 9].

dynamics such as: (1) the interaction between porous soil and water - where the water wets the solid components of the soil; (2) enhanced oil recovery processes - where the process permeates water into oil-wet porous media. However, the mineral floatation in these processes is often based on the selective wetting characteristics of the mineral particles [43]. Two key mechanisms [44] governs wettability alteration of surfaces - cleaning and coating. Cleaning involves the use of surface-active agents to desorb surfaces e.g. surfactants induced wettability alteration, where cationic surfactants can desorb the hydrophobic layer on a surface while changing the surface toward hydrophilic condition. Whereas coating involves covering a hydrophobic surface with a hydrophilic material, e.g. hydrophilic zirconium nanoparticle can adsorb on hydrophobic rock surface and form nanotextures capable of coating the hydrophobic surfaces. At large scales, wetting or non-wetting plays an essential role during oil recovery [45]. Inadequate formation wetting can prohibit efficient hydrocarbon flow, which in turn hinders the oil, gas or water movement or distribution through the pore spaces, as such fluids may appear to have flowed whereas its distribution through the pore spaces is hindered owing to poor rock wetting. Assuming a system contains only three phases (solid, liquid, and vapor), for any two of these phases to be in contact, a transitional area of molecular dimensions occurs owing to the compositional alteration of the system that leads to phase changes. For example, if a non-volatile molecular smooth solid is in contact with an inert gas, it is expected that the system will exhibit a transition region thickness of about a molecule, this would cause a change from solid molecules to gas molecules. Whereas, if similar trend occurs on an irregular surface, the transition region would reflect the physical non-uniformity of the surface and a concentration profile of the region would indicate the existence or non-existence of the solid phase. Similar concentration profile phenomenon holds for solid-liquid systems; however, the related specifics are dependent on the solubility of the solid in the liquid or the solubility of the liquid in the solid [46, 47]. In a typical solid-liquid-vapor three-phase system [48], the system would exhibit a completely dry behavior if there is an intrusion of a macroscopic vapor layer between the solid and the liquid; a partial wetting behavior if the droplet is bounded by microscopic thin film that is adsorbed on the surface of the solid; and

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complete wetting occurs due to macroscopic adsorbed thick wetting layer.

With respect to petroleum reservoir rocks, wetting is ascribed to the measurement of the reservoir rocks affinity for water or oil in a typical rock-fluid-oil system. An understanding of the wetting preference of rock is vital, as it unveils the mechanisms behind fluid flow in porous media, soil decontamination process evaluations, and ultimately promotes recovery efficiency. Reservoirs exhibit different wetting inclinations: water-wet, oil-wet, or intermediate-wet (**Figure 2**). Reservoir rocks considered as water-wet have high affinity for water and water predominantly occupies the tiny rock pores as well as the surface of the formation rock. Whereas, oil-wet reservoir rocks have high affinity for oil and such oil mainly occupies the tiny rock pores and the formation rock surface. For example; in controlled laboratory experiments involving the manipulations of cores or rock samples, the samples are usually cleaned and modified to a preferential wetting state. If such samples have high affinity for water or were originally water wet, then saturated to a suitable oil-wet state, the rock surface becomes even more oil-wet or hydrophobic upon exposure to oil under efficient and favorable treatment conditions. However, this does not influence the actual wetting affinity of the rock. The actual wetting affinity can be affirmed by exposing such hydrophobic rock to a water imbibition test. The water imbibing potential of the rock can be used to predict its wetting affinity.

In the face of the diverse functionalities of the nanoparticle, a major impediment in the manipulation and application of nanoparticle is the colloidal stability control. Nanoparticle tends to agglomerate when in suspensions irrespective of its small size. This has remained an issue with the production and utilization of nanoparticle based fluid as this behavior impacts the overall fluid stability. Such agglomeration can impede fluid flow characteristics in porous media as well as in flow based cooling applications [35]. Since nanofluids are typically produced in small quantities at laboratory scale, there is high potentials of yielding sufficiently well dispersed, homogenized, and stable fluids. However, homogeneous nanoparticle dispersion is often a challenge owing to agglomerating or clustering tendencies. The agglomeration inclination or clustering behavior of nanoparticle is dependent on the nanoparticles properties, particle concentrations, production methods, nature of dispersants, fluid homogeneity and stability. The nanofluids stability is vital for process efficiency as instability can influence the particles functionalities. Fedele et al. [19] reported stability evaluation of nanoparticle via a comparison of various preparation methods such as ball milling, sonication, and high-pressure homogenization. The ball milling method produced the least stable fluids when compared to sonication and homogenization, which produced better stable fluid. The use of magnetic stirrer or ball milling method has been shown to be rather insufficient for stable nanofluid formulation [23]. Similarly, Roustaei and Bagherzadeh [20] reported sonication and homogenization [21–23] as the most efficient methods.

An approach to ensure the stability and homogeneity of nanofluids aside the use of additives or stabilizers, is the uniform dispersibility of the particles in the solution. Attaining high-performance heat transfer nanofluids require efficient dispersion of the particles in the base fluid [8, 12, 40, 41] and ensuring an approximately monodispersed or non-agglomerated nanoparticle in liquids during the production of the suspensions. Thus, the fluid stability and excellent particle dispersion in base fluids can be significantly improved by using appropriate dispersants, suitable fluid production methods, and surface treated nanoparticles. Suitable dispersal and fluid production methods are vital to achieving desirable properties and uniform distribution of the particles in the system which can further prevent issues of agglomeration and can also improve the mechanical properties such as strength and ductility of the system [42]. Careful consideration should also be given to the concentration of the nanoparticles, as high particle concentration volume can propel high particle agglomeration.

#### **2. Wettability**

Wetting applies to several practical processes and a variety of industries such as energy, marine, manufacturing and materials. Wetting processes often involve the interaction of solids such as porous material, suspensions, or fibers, and liquids - water, ink, dye or lubricants. Typical indications of solid-liquid wetting can be illustrated using standard scenarios to correlate the dynamics such as: (1) the interaction between porous soil and water - where the water wets the solid components of the soil; (2) enhanced oil recovery processes - where the process permeates water into oil-wet porous media. However, the mineral floatation in these processes is often based on the selective wetting characteristics of the mineral particles [43]. Two key mechanisms [44] governs wettability alteration of surfaces - cleaning and coating. Cleaning involves the use of surface-active agents to desorb surfaces e.g. surfactants induced wettability alteration, where cationic surfactants can desorb the hydrophobic layer on a surface while changing the surface toward hydrophilic condition. Whereas coating involves covering a hydrophobic surface with a hydrophilic material, e.g. hydrophilic zirconium nanoparticle can adsorb on hydrophobic rock surface and form nanotextures capable of coating the hydrophobic surfaces. At large scales, wetting or non-wetting plays an essential role during oil recovery [45]. Inadequate formation wetting can prohibit efficient hydrocarbon flow, which in turn hinders the oil, gas or water movement or distribution through the pore spaces, as such fluids may appear to have flowed whereas its distribution through the pore spaces is hindered owing to poor rock wetting. Assuming a system contains only three phases (solid, liquid, and vapor), for any two of these phases to be in contact, a transitional area of molecular dimensions occurs owing to the compositional alteration of the system that leads to phase changes. For example, if a non-volatile molecular smooth solid is in contact with an inert gas, it is expected that the system will exhibit a transition region thickness of about a molecule, this would cause a change from solid molecules to gas molecules. Whereas, if similar trend occurs on an irregular surface, the transition region would reflect the physical non-uniformity of the surface and a concentration profile of the region would indicate the existence or non-existence of the solid phase. Similar concentration profile phenomenon holds for solid-liquid systems; however, the related specifics are dependent on the solubility of the solid in the liquid or the solubility of the liquid in the solid [46, 47]. In a typical solid-liquid-vapor three-phase system [48], the system would exhibit a completely dry behavior if there is an intrusion of a macroscopic vapor layer between the solid and the liquid; a partial wetting behavior if the droplet is bounded by microscopic thin film that is adsorbed on the surface of the solid; and complete wetting occurs due to macroscopic adsorbed thick wetting layer.

in a fluid in a single combined process, which is suitable for nanofluids with high-conductivity metals contents. Whereas with the two-step method, production process is performed in two separate steps, firstly, the nanoparticle is produced, and then the produced nanoparticle is dis-

In the face of the diverse functionalities of the nanoparticle, a major impediment in the manipulation and application of nanoparticle is the colloidal stability control. Nanoparticle tends to agglomerate when in suspensions irrespective of its small size. This has remained an issue with the production and utilization of nanoparticle based fluid as this behavior impacts the overall fluid stability. Such agglomeration can impede fluid flow characteristics in porous media as well as in flow based cooling applications [35]. Since nanofluids are typically produced in small quantities at laboratory scale, there is high potentials of yielding sufficiently well dispersed, homogenized, and stable fluids. However, homogeneous nanoparticle dispersion is often a challenge owing to agglomerating or clustering tendencies. The agglomeration inclination or clustering behavior of nanoparticle is dependent on the nanoparticles properties, particle concentrations, production methods, nature of dispersants, fluid homogeneity and stability. The nanofluids stability is vital for process efficiency as instability can influence the particles functionalities. Fedele et al. [19] reported stability evaluation of nanoparticle via a comparison of various preparation methods such as ball milling, sonication, and high-pressure homogenization. The ball milling method produced the least stable fluids when compared to sonication and homogenization, which produced better stable fluid. The use of magnetic stirrer or ball milling method has been shown to be rather insufficient for stable nanofluid formulation [23]. Similarly, Roustaei and Bagherzadeh [20] reported sonication and homogenization

An approach to ensure the stability and homogeneity of nanofluids aside the use of additives or stabilizers, is the uniform dispersibility of the particles in the solution. Attaining high-performance heat transfer nanofluids require efficient dispersion of the particles in the base fluid [8, 12, 40, 41] and ensuring an approximately monodispersed or non-agglomerated nanoparticle in liquids during the production of the suspensions. Thus, the fluid stability and excellent particle dispersion in base fluids can be significantly improved by using appropriate dispersants, suitable fluid production methods, and surface treated nanoparticles. Suitable dispersal and fluid production methods are vital to achieving desirable properties and uniform distribution of the particles in the system which can further prevent issues of agglomeration and can also improve the mechanical properties such as strength and ductility of the system [42]. Careful consideration should also be given to the concentration of the nanoparticles, as high

Wetting applies to several practical processes and a variety of industries such as energy, marine, manufacturing and materials. Wetting processes often involve the interaction of solids such as porous material, suspensions, or fibers, and liquids - water, ink, dye or lubricants. Typical indications of solid-liquid wetting can be illustrated using standard scenarios to correlate the

particle concentration volume can propel high particle agglomeration.

persed in a fluid – this is considered an effective strategy for commercial use [8, 9].

[21–23] as the most efficient methods.

330 Novel Nanomaterials - Synthesis and Applications

**2. Wettability**

With respect to petroleum reservoir rocks, wetting is ascribed to the measurement of the reservoir rocks affinity for water or oil in a typical rock-fluid-oil system. An understanding of the wetting preference of rock is vital, as it unveils the mechanisms behind fluid flow in porous media, soil decontamination process evaluations, and ultimately promotes recovery efficiency. Reservoirs exhibit different wetting inclinations: water-wet, oil-wet, or intermediate-wet (**Figure 2**). Reservoir rocks considered as water-wet have high affinity for water and water predominantly occupies the tiny rock pores as well as the surface of the formation rock. Whereas, oil-wet reservoir rocks have high affinity for oil and such oil mainly occupies the tiny rock pores and the formation rock surface. For example; in controlled laboratory experiments involving the manipulations of cores or rock samples, the samples are usually cleaned and modified to a preferential wetting state. If such samples have high affinity for water or were originally water wet, then saturated to a suitable oil-wet state, the rock surface becomes even more oil-wet or hydrophobic upon exposure to oil under efficient and favorable treatment conditions. However, this does not influence the actual wetting affinity of the rock. The actual wetting affinity can be affirmed by exposing such hydrophobic rock to a water imbibition test. The water imbibing potential of the rock can be used to predict its wetting affinity.

oil-wet nature of carbonate formation is due to its surface charges, which tend to attract negatively charged carboxylic acids compounds in crude oils [59–61]. Ideally, the formations positive surface charges attract crude oil acidic components. Carbonate reservoirs are problematic, as the complex wetting characteristics of this reservoir make the production capacity quite different in comparison to other conventional formations. Typically, an enormous capacity of the original oil in place is left stranded in this formation after primary and secondary oil recovery approaches are employed. Such approaches have been implemented for several decades, however, the fraction of recoverable oil from this reservoir is less than two-thirds [39, 62]. Fractured reservoir with enormous oil resources in its matrix requires advanced approaches for efficient recovery. Although water flooding enhances productivity in this reservoir by imbibing water from the formation fractures into the rock matrix, while enhancing oil flow out of the matrix through the fractures to the production well, this is mainly achievable if the capillary driving force is robust and efficient as it influences recovery efficiency, and the interaction between the matrix and the fracture is required for oil recovery from the formation matrix. Capillary forces have a significant effect on recovery capacities, however, its impact is greatly dependent on the nature of the reservoir, whether it is fractured or non-fractured. For non-fractured reservoirs, the presence of strong capillary forces during water flooding traps oil, however, the residual oil saturation becomes relatively high. Hence, the need for a reduction of the oil-water interfacial tension forces in order to remobilize residual oil in such formations. Whereas, for fractured reservoirs such as carbonate, the key driving force for efficient oil displacement in this formation is the spontaneous imbibition of water [63, 64]. Capillary effect and wettability are the underlying mechanisms in this case. This effect is attainable if the formation rock is hydrophilic [65]. Strong capillary effect occurs if the matrix is sufficiently water-wet and the fracture network holds enough water. Ideally, this is not the case with carbonate reservoir, as it is characterized by complex microstructures and poor rock wettability (intermediate-wet or oil-wet). This behavior impedes productiv-

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ity, hence, harnessing substantial oil from this formation is rather unsatisfactory.

Understanding wettability in oil-wet carbonate reservoir is challenging owing to the complex nature of crude oil, and its characterization is even more difficult. Crude oil contains polar compounds which are normally surface-active and capable of altering reservoir rock surfaces when adsorbed [55, 66–69]. Among such polar compounds, asphaltenes and resins have the most polar oil fractions with high surface activity. Asphaltenes are known for their propensity to self-associate in solution, with high surface adsorption behavior. Surface wettability alteration is mainly caused by the asphaltenes through interaction of its polar functional component with the surface polar sites, which leads to operational problems, and such interaction poses even more complexities [66, 70–75]. Since the distribution of the oil in the reservoir is dependent on the degree of the reservoir rock wettability, it is, therefore, imperative to quantify the balance of forces existing at the line of contacts between the rock, oil, and water. Typically, if the oil and water are in contact with the rock surface, either of these fluids will exhibit displacement tendencies of the other or attain equilibrium as the fluids create an angle of contact with the rock. However, such interactions can be affected by factors such as the mineralogy of the rock surface, brine composition, pore roughness and the nature of the oil. Contact angle and spontaneous imbibition tests are key approaches for assessing formation wettability among other approaches such as relative permeability, capillary pressure/displacement

**Figure 2.** Rock surface wetting transition from hydrophobic to hydrophilic. Left: Oil-wet (105–180◦ ); Center: Intermediatewet (75–105◦ ); right: Water-wet (0–75◦ ).

Ideally, if the rock has high affinity for water then the oil will be displaced from the surface of the rock by water. Whereas if a rock with high affinity for oil is saturated with water, and then the rock is placed in an oil-wet environment, the oil will displace the water from the rock surface while efficiently imbibing into the rock pores. In the absence of an actual inclination for water or oil, the formation rock is considered intermediate wetting. Aside from these key-wetting preferences, there also exists fractional wetting where the formation rock exhibit different wetting inclination in different sections of the rock [49–53].

#### **2.1. Carbonate porous media and wettability challenges**

Reservoir rocks considered as porous media are formations with an interconnected network of pores or voids characterized by the rock's porosity, and physical and textural properties that exhibit a dependency on the formations constituents. Oil recovery exhibits great dependency on the formation wettability as it controls the fluid displacements of the wetting and non-wetting phase at the pore scale. Reservoir wettability is a prime factor for determining the microscopic displacement efficiency in the swept regions of a waterflood. Originally, reservoirs were strongly water-wet, and the formation traps were initially filled with water, thus the surface of reservoir rocks had high affinity for water in the presence of oil. However, overtime, oil migrated into such formations forming firm adsorbed layers of heavy hydrocarbons that poise several challenges and cannot be altered via gasoline or mere solvent applications. The oil migration and accumulation cause water to be retained in the rock pore spaces due to capillary pressure, while the rock pores surface become covered by oil, and water existed on such surfaces in the form of films. Such effect is primarily due to the rock surface wettability changes owing to the ease of invasion by a wetting fluid, which causes lithological variances. The level of oil migration also determines the formations wetting state. For instance, if the migrated oil is negligible, the possibilities are that the neighboring formations will be more oil wetting, while the tight regions of the formation would exhibit more water-wet behavior [49–55]. This behavior is more prevalent in carbonate rocks owing to the oil-wet character of this formation, which is still poorly understood.

It is well established that heterogeneous carbonate rocks are more prevalent globally. Carbonate rocks exhibit complex microstructures [56–58] and its complex nature impacts reservoir wetting preference. These formations are predominantly naturally fractured, and exhibits diverse wetting conditions; intermediate-wet or oil-wet behavior with as high as over 80% oil-wetness. The oil-wet nature of carbonate formation is due to its surface charges, which tend to attract negatively charged carboxylic acids compounds in crude oils [59–61]. Ideally, the formations positive surface charges attract crude oil acidic components. Carbonate reservoirs are problematic, as the complex wetting characteristics of this reservoir make the production capacity quite different in comparison to other conventional formations. Typically, an enormous capacity of the original oil in place is left stranded in this formation after primary and secondary oil recovery approaches are employed. Such approaches have been implemented for several decades, however, the fraction of recoverable oil from this reservoir is less than two-thirds [39, 62]. Fractured reservoir with enormous oil resources in its matrix requires advanced approaches for efficient recovery. Although water flooding enhances productivity in this reservoir by imbibing water from the formation fractures into the rock matrix, while enhancing oil flow out of the matrix through the fractures to the production well, this is mainly achievable if the capillary driving force is robust and efficient as it influences recovery efficiency, and the interaction between the matrix and the fracture is required for oil recovery from the formation matrix. Capillary forces have a significant effect on recovery capacities, however, its impact is greatly dependent on the nature of the reservoir, whether it is fractured or non-fractured. For non-fractured reservoirs, the presence of strong capillary forces during water flooding traps oil, however, the residual oil saturation becomes relatively high. Hence, the need for a reduction of the oil-water interfacial tension forces in order to remobilize residual oil in such formations. Whereas, for fractured reservoirs such as carbonate, the key driving force for efficient oil displacement in this formation is the spontaneous imbibition of water [63, 64]. Capillary effect and wettability are the underlying mechanisms in this case. This effect is attainable if the formation rock is hydrophilic [65]. Strong capillary effect occurs if the matrix is sufficiently water-wet and the fracture network holds enough water. Ideally, this is not the case with carbonate reservoir, as it is characterized by complex microstructures and poor rock wettability (intermediate-wet or oil-wet). This behavior impedes productivity, hence, harnessing substantial oil from this formation is rather unsatisfactory.

Ideally, if the rock has high affinity for water then the oil will be displaced from the surface of the rock by water. Whereas if a rock with high affinity for oil is saturated with water, and then the rock is placed in an oil-wet environment, the oil will displace the water from the rock surface while efficiently imbibing into the rock pores. In the absence of an actual inclination for water or oil, the formation rock is considered intermediate wetting. Aside from these key-wetting preferences, there also exists fractional wetting where the formation rock exhibit

); Center: Intermediate-

Reservoir rocks considered as porous media are formations with an interconnected network of pores or voids characterized by the rock's porosity, and physical and textural properties that exhibit a dependency on the formations constituents. Oil recovery exhibits great dependency on the formation wettability as it controls the fluid displacements of the wetting and non-wetting phase at the pore scale. Reservoir wettability is a prime factor for determining the microscopic displacement efficiency in the swept regions of a waterflood. Originally, reservoirs were strongly water-wet, and the formation traps were initially filled with water, thus the surface of reservoir rocks had high affinity for water in the presence of oil. However, overtime, oil migrated into such formations forming firm adsorbed layers of heavy hydrocarbons that poise several challenges and cannot be altered via gasoline or mere solvent applications. The oil migration and accumulation cause water to be retained in the rock pore spaces due to capillary pressure, while the rock pores surface become covered by oil, and water existed on such surfaces in the form of films. Such effect is primarily due to the rock surface wettability changes owing to the ease of invasion by a wetting fluid, which causes lithological variances. The level of oil migration also determines the formations wetting state. For instance, if the migrated oil is negligible, the possibilities are that the neighboring formations will be more oil wetting, while the tight regions of the formation would exhibit more water-wet behavior [49–55]. This behavior is more prevalent in carbonate

rocks owing to the oil-wet character of this formation, which is still poorly understood.

It is well established that heterogeneous carbonate rocks are more prevalent globally. Carbonate rocks exhibit complex microstructures [56–58] and its complex nature impacts reservoir wetting preference. These formations are predominantly naturally fractured, and exhibits diverse wetting conditions; intermediate-wet or oil-wet behavior with as high as over 80% oil-wetness. The

different wetting inclination in different sections of the rock [49–53].

**Figure 2.** Rock surface wetting transition from hydrophobic to hydrophilic. Left: Oil-wet (105–180◦

**2.1. Carbonate porous media and wettability challenges**

).

wet (75–105◦

); right: Water-wet (0–75◦

332 Novel Nanomaterials - Synthesis and Applications

Understanding wettability in oil-wet carbonate reservoir is challenging owing to the complex nature of crude oil, and its characterization is even more difficult. Crude oil contains polar compounds which are normally surface-active and capable of altering reservoir rock surfaces when adsorbed [55, 66–69]. Among such polar compounds, asphaltenes and resins have the most polar oil fractions with high surface activity. Asphaltenes are known for their propensity to self-associate in solution, with high surface adsorption behavior. Surface wettability alteration is mainly caused by the asphaltenes through interaction of its polar functional component with the surface polar sites, which leads to operational problems, and such interaction poses even more complexities [66, 70–75]. Since the distribution of the oil in the reservoir is dependent on the degree of the reservoir rock wettability, it is, therefore, imperative to quantify the balance of forces existing at the line of contacts between the rock, oil, and water. Typically, if the oil and water are in contact with the rock surface, either of these fluids will exhibit displacement tendencies of the other or attain equilibrium as the fluids create an angle of contact with the rock. However, such interactions can be affected by factors such as the mineralogy of the rock surface, brine composition, pore roughness and the nature of the oil.

Contact angle and spontaneous imbibition tests are key approaches for assessing formation wettability among other approaches such as relative permeability, capillary pressure/displacement capillary pressure or USBM [49–52, 76]. However, there exists a remarkable variation in the test methods, which is primarily based on how much of the rock surface is exposed to the wetting phase or wetted by water. In contact angle tests, only the outer surface area of the sample is exposed to a drop of water without consideration for the inner surface of the rock, whereas, in the spontaneous imbibition tests, the whole sample is exposed to the wetting phase (**Figure 3**). Thus, the inner surface area of the rock can be accounted for upon displacement of the non-wetting phase (oil) by the wetting phase. For example, in an oil-wet carbonate rock, for oil to be displaced by the wetting phase (water/brine solutions etc.) the capillary barriers must be overcome. If the wetting phase penetrates the rock pores, two key possibilities exist; (a) rock wettability change; (b) the presence of a positive capillary due to the wettability change. Such scenarios can enhance recovery especially if the formation rock is hydrophilic. **Figure 3b** (i-ii) shows a typical case of an oil-wet rock or core sample placed in an imbibition cell containing NaCl brine solution (the wetting phase). The brine imbibes into the rock or core pores and pushes out the oil in the cores. Such expelled oil sticks on the rock surface while been collected at the top of the cell simultaneously for estimation of the recoverable oil. Formation rock with a considerable waterwet condition exhibits high potentials for allowing water into the tight rock matrix pores. Thus, more water-wet rocks allow higher rates in spontaneous imbibition with possibilities of improving recovery. However, maintaining water wetness of formation rocks depends on the extent to which the water film on the rock surface is stable. The presence of unstable water films can lead to oil migration to the rock surface (like the behavior observed in **Figure 3b**), thus, changing the rock surface wettability. With respect to a typical crude oil system, such behavior would lead to adsorption of polar compounds on the solid surface which in turn changes the wetting properties of the solid [51]. Usually the brine present in a typical carbonate reservoir exhibits a somewhat basic pH (7–8), very high concentration of Ca2+, and a very small amount of CO3 2−, thus the rock-water interface becomes positively charged [77]. The carboxylic materials present in the crude oil acts as surface-active materials, and partial dissociation of the acidic group leads to negatively charged oil-water interface. This behavior causes instability of the initial water film between the oil and the rock and the oil comes in contact with the rock yielding mixedwet characteristics. Several wetting studies have been conducted with crude oil used to alter originally water-wet surfaces to oil-wet in different systems [78–89]. For example; Standnes and

Austad [79, 80] performed a wettability test on chalk cores and calcite mineral surfaces altered by crude oil to a sufficient oil-wet state using surfactant as the surface-active agents via spontaneous imbibition. The authors reported that the cationic surfactant changed the wettability of the chalk by desorbing the organic carboxylates from the chalk surface leading to an increased oil recovery of about 70% from the chalk. Buckley and Lord [83] altered mica surface to oil-wet using series of crude oil through atomic force microscopy (AFM), and found that the oils that

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Based on the wettability issues in carbonate formations mentioned above, here, we investigated two specific metal oxide nanoparticle types of interest; zirconium oxide and nickel oxide. Firstly, their structure, morphology, and crystallinity phases were examined. Then the wetting inclinations of the nanoparticles were further tested to ascertain their solid-liquid interface behavior on basis of wettability owing to the growing interest in understanding reservoir rock wetting.

Nickel oxide (NiO) is a metal oxide nanoparticle in the form of dark gray (**Figure 4**) crystalline solid. This material has good chemical stability, excellent electrical properties, large exciton binding energy, and a stable wide band gap >3 eV [90–94]. NiO is considered a p-type semiconductor metal oxide particle, thus, a candidate for p-type transparent conducting films [92, 95, 96]. This material also exhibits good optical and magnetic properties; anodic electrochromism properties, excellent durability, large spin optical density, and displays strong insulating property [92, 97–100]. On the basis of reactivity, NiO surface that is considered imperfect acts as a useful oxidation catalyst, although, a perfect NiO is weakly reactive. The perfect surface inertness of NiO is in accordance with the non-metallic properties of the material bulk system [92]. NiO is suitable for usage in electrochemical super-capacitors, dye-sensitized photo cathodes applications and smart windows applications [92, 97–100]. Other processes where uniform size, well-dispersed NiO nanoparticles are also suitable are in heterogeneous catalytic processes, design of ceramics, magnetic applications, fabrication of gas sensors, films, and cathodes of alkaline batteries [101–109]. Although NiO appears to be suitable for a wide variety of processes, its property and functionality depend on the pore morphology, pore matrix-interface and process application. For instance, a very high specific surface area is required for this material in catalytic applications, whereas a rather dense material is required for cathodic applications [96].

) is a metal oxide nanoparticle in the form of white (**Figure 4**) crystalline

has high refractive index, high melting point of 2680°C, wide region of low absorp-

tion from the near-UV > 240 nm to mid-IR range < 8 mm and high resistance against oxidation [110, 111]. This material is also characterized by high breakdown field, good thermal stability, large band gap >5ev, and high-dielectric constant >20 [112–115], thus, the material has been considered a potential challenger of other nanoparticles. In a recent report, it was established that

exhibits superior chemical and thermal stability than alumina and silica nanoparticles [112].

produce the thickest coatings exhibited the highest water-advancing angles.

**3. Nanoparticles and its effect on solid-liquid interface**

**3.1. Nanoparticle characterization**

Zirconium Oxide (ZrO2

solid. ZrO<sup>2</sup>

ZrO2

**Figure 3.** Contact angle versus spontaneous imbibition (a) contact angle: Outer surface area wetted by a drop of water on calcite sample; (b) imbibition: The whole carbonate core sample is wetted by brine (NaCl) in an imbibition cell at different temperature conditions during an imbibition experiment. As the brine imbibes into the cores, the oil is pushed out of the cores to the rock surface and collected at the top of the cell (i) ambient temperature (22 ± 1°C); (ii) 50 ± 1°C showing oil droplets that have been pushed out of the cores on the outer surface of the rocks.

Austad [79, 80] performed a wettability test on chalk cores and calcite mineral surfaces altered by crude oil to a sufficient oil-wet state using surfactant as the surface-active agents via spontaneous imbibition. The authors reported that the cationic surfactant changed the wettability of the chalk by desorbing the organic carboxylates from the chalk surface leading to an increased oil recovery of about 70% from the chalk. Buckley and Lord [83] altered mica surface to oil-wet using series of crude oil through atomic force microscopy (AFM), and found that the oils that produce the thickest coatings exhibited the highest water-advancing angles.

### **3. Nanoparticles and its effect on solid-liquid interface**

Based on the wettability issues in carbonate formations mentioned above, here, we investigated two specific metal oxide nanoparticle types of interest; zirconium oxide and nickel oxide. Firstly, their structure, morphology, and crystallinity phases were examined. Then the wetting inclinations of the nanoparticles were further tested to ascertain their solid-liquid interface behavior on basis of wettability owing to the growing interest in understanding reservoir rock wetting.

#### **3.1. Nanoparticle characterization**

2−,

capillary pressure or USBM [49–52, 76]. However, there exists a remarkable variation in the test methods, which is primarily based on how much of the rock surface is exposed to the wetting phase or wetted by water. In contact angle tests, only the outer surface area of the sample is exposed to a drop of water without consideration for the inner surface of the rock, whereas, in the spontaneous imbibition tests, the whole sample is exposed to the wetting phase (**Figure 3**). Thus, the inner surface area of the rock can be accounted for upon displacement of the non-wetting phase (oil) by the wetting phase. For example, in an oil-wet carbonate rock, for oil to be displaced by the wetting phase (water/brine solutions etc.) the capillary barriers must be overcome. If the wetting phase penetrates the rock pores, two key possibilities exist; (a) rock wettability change; (b) the presence of a positive capillary due to the wettability change. Such scenarios can enhance recovery especially if the formation rock is hydrophilic. **Figure 3b** (i-ii) shows a typical case of an oil-wet rock or core sample placed in an imbibition cell containing NaCl brine solution (the wetting phase). The brine imbibes into the rock or core pores and pushes out the oil in the cores. Such expelled oil sticks on the rock surface while been collected at the top of the cell simultaneously for estimation of the recoverable oil. Formation rock with a considerable waterwet condition exhibits high potentials for allowing water into the tight rock matrix pores. Thus, more water-wet rocks allow higher rates in spontaneous imbibition with possibilities of improving recovery. However, maintaining water wetness of formation rocks depends on the extent to which the water film on the rock surface is stable. The presence of unstable water films can lead to oil migration to the rock surface (like the behavior observed in **Figure 3b**), thus, changing the rock surface wettability. With respect to a typical crude oil system, such behavior would lead to adsorption of polar compounds on the solid surface which in turn changes the wetting properties of the solid [51]. Usually the brine present in a typical carbonate reservoir exhibits a somewhat basic pH (7–8), very high concentration of Ca2+, and a very small amount of CO3

334 Novel Nanomaterials - Synthesis and Applications

thus the rock-water interface becomes positively charged [77]. The carboxylic materials present in the crude oil acts as surface-active materials, and partial dissociation of the acidic group leads to negatively charged oil-water interface. This behavior causes instability of the initial water film between the oil and the rock and the oil comes in contact with the rock yielding mixedwet characteristics. Several wetting studies have been conducted with crude oil used to alter originally water-wet surfaces to oil-wet in different systems [78–89]. For example; Standnes and

**Figure 3.** Contact angle versus spontaneous imbibition (a) contact angle: Outer surface area wetted by a drop of water on calcite sample; (b) imbibition: The whole carbonate core sample is wetted by brine (NaCl) in an imbibition cell at different temperature conditions during an imbibition experiment. As the brine imbibes into the cores, the oil is pushed out of the cores to the rock surface and collected at the top of the cell (i) ambient temperature (22 ± 1°C); (ii) 50 ± 1°C

showing oil droplets that have been pushed out of the cores on the outer surface of the rocks.

Nickel oxide (NiO) is a metal oxide nanoparticle in the form of dark gray (**Figure 4**) crystalline solid. This material has good chemical stability, excellent electrical properties, large exciton binding energy, and a stable wide band gap >3 eV [90–94]. NiO is considered a p-type semiconductor metal oxide particle, thus, a candidate for p-type transparent conducting films [92, 95, 96]. This material also exhibits good optical and magnetic properties; anodic electrochromism properties, excellent durability, large spin optical density, and displays strong insulating property [92, 97–100]. On the basis of reactivity, NiO surface that is considered imperfect acts as a useful oxidation catalyst, although, a perfect NiO is weakly reactive. The perfect surface inertness of NiO is in accordance with the non-metallic properties of the material bulk system [92]. NiO is suitable for usage in electrochemical super-capacitors, dye-sensitized photo cathodes applications and smart windows applications [92, 97–100]. Other processes where uniform size, well-dispersed NiO nanoparticles are also suitable are in heterogeneous catalytic processes, design of ceramics, magnetic applications, fabrication of gas sensors, films, and cathodes of alkaline batteries [101–109]. Although NiO appears to be suitable for a wide variety of processes, its property and functionality depend on the pore morphology, pore matrix-interface and process application. For instance, a very high specific surface area is required for this material in catalytic applications, whereas a rather dense material is required for cathodic applications [96].

Zirconium Oxide (ZrO2 ) is a metal oxide nanoparticle in the form of white (**Figure 4**) crystalline solid. ZrO<sup>2</sup> has high refractive index, high melting point of 2680°C, wide region of low absorption from the near-UV > 240 nm to mid-IR range < 8 mm and high resistance against oxidation [110, 111]. This material is also characterized by high breakdown field, good thermal stability, large band gap >5ev, and high-dielectric constant >20 [112–115], thus, the material has been considered a potential challenger of other nanoparticles. In a recent report, it was established that ZrO2 exhibits superior chemical and thermal stability than alumina and silica nanoparticles [112].

**Figure 4.** Nanoparticles in powder form (NiO-dark gray green color; ZrO<sup>2</sup> -white color).

Similarly, Gopalan et al. [116] earlier reported that silica nanoparticles exhibit limited chemical and physical stability, as such, ZrO2 nanoparticle was considered as a better alternative and also more chemically stable than γ-alumina or silica. ZrO<sup>2</sup> has an extraordinary high catalytic effect and it is the only metal oxide nanoparticle with four chemical properties on the surface: acidic/ basic and reducing/oxidizing properties [117]. ZrO<sup>2</sup> has attracted attention in a wide variety of processes, as the material displays superior mechanical strength, high temperature resistance, high flexural strength, hardness, and low corrosion potential. As such, it can act as a catalyst, refractory, and insulator in transistors in fuel cells, electronic devices, and oxygen sensors, and also suitable for broadband interference filters, laser mirrors, and ionic conductors [118–121].

*4.1.2. Nanoparticles*

**Table 1.** Carbonate rock.

study (**Table 2**).

*4.1.3. Oil phase*

model oil.

ing point: 538.4 k; Density: 875 kg/m<sup>3</sup>

**(Wt. %)**

**Sample Concentration** 

**Table 2.** Properties of nanoparticles.

Zirconium oxide (Purity: 99.5 wt. %; density: 5.89 g/mL at 25°C (lit.)) and nickel oxide (Purity 99.5 wt. %; density: 6.67 g/mL at 25°C) nanoparticles from Sigma Aldrich were used in this

**Element Symbol Atomic concentration (%) Weight concentration (%)**

stable oil-wet state. Toluene (purity 99.9 mol. %) obtained from Sigma Aldrich was used as

**Molecular weight (g/mol)** Si) - purity ≥99.0 mol. %; boil-

**Form Color Particle Size** 

Dark gray

White < 50

**(nm)**

< 50


Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

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337

powder

powder

Dodecyltriethoxysilane obtained from Sigma Aldrich ((C18H40O3

**Chemical formula**

Zirconium Oxide (0.005–0.05) ZrO2 123.22 Nano

Nickel Oxide (0.005–0.05) NiO 74.69 Nano

**Figure 5.** Spectrum analysis of the calcite fraction of the carbonate rock.

Calcium Ca 62.76 57.24 Carbon C 10.78 24.64 Oxygen O 26.46 18.12

With respect to wettability, the recent relevance of nanoparticles in wetting processes is mainly due to the particles excellent range of physical and chemical properties as reported earlier. The materials surface and interface properties play an essential role in their overall behavior, whether during preparation or applications. However, there is a lack of understanding of nanoparticles wetting on basis of the solid-liquid interactions, especially, whether strongly hydrophobic surfaces can be rendered hydrophilic, as this is vital for EOR, soil decontamination, and carbon geo-sequestration process efficiency. Since successful oil recovery from fractured carbonate reservoirs show dependency on wettability [122], it is, therefore, necessary to establish an understanding of ZrO2 and NiO nanoparticles properties, specifically, on the key areas that facilitate their process efficiency and subsequent influence on wetting.

#### **4. Experimental procedure**

#### **4.1. Materials**

#### *4.1.1. Rock samples*

Iceland spar calcite crystals from Ward Science as a representative of carbonate formation as calcite is a predominant mineral constituent of carbonate [38, 58] as also evident in the spectrum analysis of the calcite fraction of a carbonate rock (**Figure 5**; **Table 1**).

**Figure 5.** Spectrum analysis of the calcite fraction of the carbonate rock.


**Table 1.** Carbonate rock.

Similarly, Gopalan et al. [116] earlier reported that silica nanoparticles exhibit limited chemical

and it is the only metal oxide nanoparticle with four chemical properties on the surface: acidic/

processes, as the material displays superior mechanical strength, high temperature resistance, high flexural strength, hardness, and low corrosion potential. As such, it can act as a catalyst, refractory, and insulator in transistors in fuel cells, electronic devices, and oxygen sensors, and also suitable for broadband interference filters, laser mirrors, and ionic conductors [118–121].

With respect to wettability, the recent relevance of nanoparticles in wetting processes is mainly due to the particles excellent range of physical and chemical properties as reported earlier. The materials surface and interface properties play an essential role in their overall behavior, whether during preparation or applications. However, there is a lack of understanding of nanoparticles wetting on basis of the solid-liquid interactions, especially, whether strongly hydrophobic surfaces can be rendered hydrophilic, as this is vital for EOR, soil decontamination, and carbon geo-sequestration process efficiency. Since successful oil recovery from fractured carbonate reservoirs show dependency on wettability [122], it is, therefore, necessary to

Iceland spar calcite crystals from Ward Science as a representative of carbonate formation as calcite is a predominant mineral constituent of carbonate [38, 58] as also evident in the spec-

areas that facilitate their process efficiency and subsequent influence on wetting.

trum analysis of the calcite fraction of a carbonate rock (**Figure 5**; **Table 1**).

nanoparticle was considered as a better alternative and also


and NiO nanoparticles properties, specifically, on the key

has an extraordinary high catalytic effect

has attracted attention in a wide variety of

and physical stability, as such, ZrO2

336 Novel Nanomaterials - Synthesis and Applications

establish an understanding of ZrO2

**4. Experimental procedure**

**4.1. Materials**

*4.1.1. Rock samples*

more chemically stable than γ-alumina or silica. ZrO<sup>2</sup>

**Figure 4.** Nanoparticles in powder form (NiO-dark gray green color; ZrO<sup>2</sup>

basic and reducing/oxidizing properties [117]. ZrO<sup>2</sup>

#### *4.1.2. Nanoparticles*

Zirconium oxide (Purity: 99.5 wt. %; density: 5.89 g/mL at 25°C (lit.)) and nickel oxide (Purity 99.5 wt. %; density: 6.67 g/mL at 25°C) nanoparticles from Sigma Aldrich were used in this study (**Table 2**).

#### *4.1.3. Oil phase*

Dodecyltriethoxysilane obtained from Sigma Aldrich ((C18H40O3 Si) - purity ≥99.0 mol. %; boiling point: 538.4 k; Density: 875 kg/m<sup>3</sup> - **Figure 6**) was used for altering samples to sufficiently stable oil-wet state. Toluene (purity 99.9 mol. %) obtained from Sigma Aldrich was used as model oil.


**Table 2.** Properties of nanoparticles.

*4.3.1. Contact Angle*

were exposed to the formulated ZrO2

*4.3.2. Mechanistic quantification*

*4.3.3. X-ray diffraction (XRD)*

detector.

microscope and scanning electron microscope.

*4.3.4. Scanning electron microscope (SEM)*

**5. Results and discussion**

(**Figure 7**). The ZrO<sup>2</sup>

**5.1. Scanning electron microscope**

ness of SEM for morphological evaluations [129–134].

The scanning electron microscope images show the micrograph of ZrO2

Contact angle (θ) was used as the deterministic tool for wettability assessments. The aged samples

the substrates were removed from the nanofluids and dried. A water droplet was dispensed on the modified calcite substrate and a high-performance microscopic camera (Basler scA 640–70 fm, pixel size =7.4 μm; frame rate = 71 fps; Fujinon CCTV lens: HF35HA-1B; 1:1.6/35 mm) was used to capture the water drop dispensing process. The advancing and receding contact angles were measured using a tilting stage [127] for water contact angle in air. Further analysis of the drop was done using Image J software and the standard deviation was ±3 based on replicate measurements.

Mechanistic investigation of samples was achieved by X-ray powder diffraction, atomic force

Samples were prepared by placing the fine powders in a sample holder that has been well smeared on a glass slide for measurement in a powdered x-ray diffractometer. Diffraction arises through constructive interference due to the illumination of periodic structures of a given spacing with the light of a similar wavelength [128]. The X-ray diffraction patterns of the nanoparticle samples were recorded using powder diffractometer D8 advance (Bruker AXS, Germany), with a copper K alpha radiation source at 40 kV and 40 mA with a LynxEye

The surface morphology of the treated and untreated samples was characterized by scanning electron microscopy - Zeiss Neon 40EsB FIBSEM with an Oxford Instruments x-act Inca SDD x-ray detector and Inca software, and scanning transmission electron microscopy - Tescan Mira3 FESEM instrument. High electron beam was used to scan over the surface of the sample for improved surface characterization. Several researchers have also reported the effective-

range of 25–40 nm, while the NiO nanoparticle displays hexagonal-like shaped particles in the range of 10–20 nm. The nanoparticles exhibited approximately uniform size distribution and high trends of finely dispersed particles in the bulk state, thus, an indication of low particleparticle agglomeration inclinations. This behavior can be attributed to the intrinsic properties of metal oxide (superior stability) and preparation method (homogenization - Section 1).

nanoparticle exhibits a distribution of sphere-like shaped particles in the

and NiO nanofluids for a fixed period of one hour (1 h). Then

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339

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

and NiO nanoparticles

**Figure 6.** Structure of silane and model oil (A) Dodecyltriethoxysilane; (B) toluene.

#### *4.1.4. Aqueous phase*

Sodium Chloride (purity ≥99.5 mol. %) from Rowe Scientific and ultrapure de-ionized water from David Gray was used. The sodium chloride was dissolved in deionized water to achieve desired concentrations using a 220 V/50 Hz magnetic stirrer.

#### **4.2. Sample preparation**

Sample preparation which accounts for sample treatments and techniques used, is an important requirement in wetting analysis. Proper sample preparation, as well as, adequate sample quality and cleanliness are essential to eliminate any chances of methodical inaccuracies.

#### *4.2.1. Calcite cleaning*

The mineral crystals (calcite) originally hydrophilic were cleaned with analytical reagent grade acetone and methanol (Rowe Scientific Pty. Ltd), and de-ionized water (David Gray & Co. Ltd). This was done to remove surface fragments and inorganic contaminants. Subsequently, the samples were exposed to air plasma for 15 mins [123–125] to remove any residual organic contaminants.

#### *4.2.2. Aging*

The clean samples were modified to oil-wet by aging in the oil phase (dodecyltriethoxysilane) for 12 h at 90°C. Samples were then separated from the oil phase, cleaned with methanol, and deionized water to remove excess silane from the surface of the rock and dried.

#### *4.2.3. Nanofluid formulation*

ZrO2 and NiO nanoparticles (Concentration - 0.005 - 0.05 wt. %) were mixed with a fixed amount of dispersals. To ensure adequate particle dispersal in the base fluid and the fluid uniformity, all fluids were formulated using high frequency ultrasonic homogenizer (a 300VT ultrasonic homogenizer and a titanium micro tip of 9.5 mm diameter) as also reported in literature [21–23, 126]. The formulations were kept in a cool place away from heat and light and the nanofluids were subjected to visual monitoring for a fixed period to ensure clear and stable solutions.

#### **4.3. Wettability quantification**

Wettability quantification was achieved via contact angle measurement and mechanistic approaches.

#### *4.3.1. Contact Angle*

Contact angle (θ) was used as the deterministic tool for wettability assessments. The aged samples were exposed to the formulated ZrO2 and NiO nanofluids for a fixed period of one hour (1 h). Then the substrates were removed from the nanofluids and dried. A water droplet was dispensed on the modified calcite substrate and a high-performance microscopic camera (Basler scA 640–70 fm, pixel size =7.4 μm; frame rate = 71 fps; Fujinon CCTV lens: HF35HA-1B; 1:1.6/35 mm) was used to capture the water drop dispensing process. The advancing and receding contact angles were measured using a tilting stage [127] for water contact angle in air. Further analysis of the drop was done using Image J software and the standard deviation was ±3 based on replicate measurements.

#### *4.3.2. Mechanistic quantification*

*4.1.4. Aqueous phase*

338 Novel Nanomaterials - Synthesis and Applications

**4.2. Sample preparation**

*4.2.1. Calcite cleaning*

*4.2.3. Nanofluid formulation*

**4.3. Wettability quantification**

*4.2.2. Aging*

ZrO2

approaches.

Sodium Chloride (purity ≥99.5 mol. %) from Rowe Scientific and ultrapure de-ionized water from David Gray was used. The sodium chloride was dissolved in deionized water to achieve

Sample preparation which accounts for sample treatments and techniques used, is an important requirement in wetting analysis. Proper sample preparation, as well as, adequate sample quality and cleanliness are essential to eliminate any chances of methodical inaccuracies.

The mineral crystals (calcite) originally hydrophilic were cleaned with analytical reagent grade acetone and methanol (Rowe Scientific Pty. Ltd), and de-ionized water (David Gray & Co. Ltd). This was done to remove surface fragments and inorganic contaminants. Subsequently, the samples were exposed to air plasma for 15 mins [123–125] to remove any residual organic contaminants.

The clean samples were modified to oil-wet by aging in the oil phase (dodecyltriethoxysilane) for 12 h at 90°C. Samples were then separated from the oil phase, cleaned with methanol, and

 and NiO nanoparticles (Concentration - 0.005 - 0.05 wt. %) were mixed with a fixed amount of dispersals. To ensure adequate particle dispersal in the base fluid and the fluid uniformity, all fluids were formulated using high frequency ultrasonic homogenizer (a 300VT ultrasonic homogenizer and a titanium micro tip of 9.5 mm diameter) as also reported in literature [21–23, 126]. The formulations were kept in a cool place away from heat and light and the nanofluids were subjected to visual monitoring for a fixed period to ensure clear and stable solutions.

Wettability quantification was achieved via contact angle measurement and mechanistic

deionized water to remove excess silane from the surface of the rock and dried.

desired concentrations using a 220 V/50 Hz magnetic stirrer.

**Figure 6.** Structure of silane and model oil (A) Dodecyltriethoxysilane; (B) toluene.

Mechanistic investigation of samples was achieved by X-ray powder diffraction, atomic force microscope and scanning electron microscope.

#### *4.3.3. X-ray diffraction (XRD)*

Samples were prepared by placing the fine powders in a sample holder that has been well smeared on a glass slide for measurement in a powdered x-ray diffractometer. Diffraction arises through constructive interference due to the illumination of periodic structures of a given spacing with the light of a similar wavelength [128]. The X-ray diffraction patterns of the nanoparticle samples were recorded using powder diffractometer D8 advance (Bruker AXS, Germany), with a copper K alpha radiation source at 40 kV and 40 mA with a LynxEye detector.

#### *4.3.4. Scanning electron microscope (SEM)*

The surface morphology of the treated and untreated samples was characterized by scanning electron microscopy - Zeiss Neon 40EsB FIBSEM with an Oxford Instruments x-act Inca SDD x-ray detector and Inca software, and scanning transmission electron microscopy - Tescan Mira3 FESEM instrument. High electron beam was used to scan over the surface of the sample for improved surface characterization. Several researchers have also reported the effectiveness of SEM for morphological evaluations [129–134].

#### **5. Results and discussion**

#### **5.1. Scanning electron microscope**

The scanning electron microscope images show the micrograph of ZrO2 and NiO nanoparticles (**Figure 7**). The ZrO<sup>2</sup> nanoparticle exhibits a distribution of sphere-like shaped particles in the range of 25–40 nm, while the NiO nanoparticle displays hexagonal-like shaped particles in the range of 10–20 nm. The nanoparticles exhibited approximately uniform size distribution and high trends of finely dispersed particles in the bulk state, thus, an indication of low particleparticle agglomeration inclinations. This behavior can be attributed to the intrinsic properties of metal oxide (superior stability) and preparation method (homogenization - Section 1).

**5.3. X-ray diffraction analysis**

of the ZrO2

cases (ZrO2

while the ZrO2

**5.4. Contact angle**

**Figure 9.** XRD patterns of the ZrO<sup>2</sup>

and NiO nanoparticles.

of the pure phase formation of the ZrO2

of the nanoparticles were also identified. Pure ZrO<sup>2</sup>

To better understand the crystallographic nature of ZrO<sup>2</sup>

als were further characterized using X-ray Diffraction (XRD). The XRD peaks usually exhibit different patterns and positioning. The pattern of the XRD of a specific sample is mainly dependent on the different arrangements of the atoms. The unit cell dimensions and angles determine the positions of the peaks. Whereas, the types and positions of the atoms within the unit cell determine the intensities of the peaks [128]. **Figure 9** shows the typical XRD patterns

fication were 2theta scan range (degree): 7.5–90; Step size (degree): 0.015; Time/step: 0.7 s and total scan time of approximately 1 hr. The XRD pattern indicates the crystallographic structure of the nanoparticles. Strong and sharp diffraction peaks at 2θ values were observed in both

and the pure NiO exhibits a cubic phase (**Figure 10** (ii)), consistent with literature [92, 135].

An understanding of surface chemistry is imperative for evaluating wetting behavior as porous media wetting are influenced by the rock surface morphology, as well as, the chemical compositions. Surface chemistry modifications of materials facilitate short-ranged chemical interactions. This phenomenon is predominantly governed by the surface and interfacial interactions, which act over the scale of molecules, and electrostatic surface forces that determine the extent to which

(in red) and NiO (black) nanoparticles. The scan parameters used for phase identi-


diffraction Peaks value were 28.5, 31.5, 34.5, 50.5 etc. The peaks are indications

and NiO nanoparticles. The crystallographic phases

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

exhibits a tetragonal phase (**Figure 10** (i)),

and NiO nanoparticles, the materi-

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341

**Figure 7.** SEM images of: (a) ZrO<sup>2</sup> ; (b) NiO nanoparticles.

#### **5.2. Particle size and surface area**

Particle size plays a vital role in the nanoparticle characterization as their physical and chemical properties greatly depend on the particle size. The small particle size of nanoparticles yields important features such as surface area. Nanoparticle size and surface area are interrelated; as the nanoparticle size becomes negligible, the particle surface area increases. Bulk materials as opposed to nanoparticle exhibit larger particle sizes (nanoparticle avarage diameter: <100 nm; microparticle >1 μm) with tons of atoms on the inside of the particle and limited atoms at the surface, whereas, with nanoparticles more atoms are predominantly on the outer surface of the particles. Such high surface area enables the bonding of other materials on the particle surface and lead to the generation of even much stronger materials that promote better interaction with neighboring atoms or ions. Ascertaining the nanoparticles size is essential as it affects particulate materials properties and can act as an approach to determine the quality and performance of these materials. The particle size of the ZrO2 and NiO nanoparticles was investigated to obtain more accurate and precise size of the particles. **Figure 8** shows that the ZrO2 particle size was 21–35 nm and NiO was in the range of 10–12 nm. The average particle diameter for ZrO<sup>2</sup> ~ 28 nm and the average value for NiO was ~ 12 nm.

**Figure 8.** Particle size morphology of a) ZrO2 ; b) NiO nanoparticles (<50 nm).

#### **5.3. X-ray diffraction analysis**

To better understand the crystallographic nature of ZrO<sup>2</sup> and NiO nanoparticles, the materials were further characterized using X-ray Diffraction (XRD). The XRD peaks usually exhibit different patterns and positioning. The pattern of the XRD of a specific sample is mainly dependent on the different arrangements of the atoms. The unit cell dimensions and angles determine the positions of the peaks. Whereas, the types and positions of the atoms within the unit cell determine the intensities of the peaks [128]. **Figure 9** shows the typical XRD patterns of the ZrO2 (in red) and NiO (black) nanoparticles. The scan parameters used for phase identification were 2theta scan range (degree): 7.5–90; Step size (degree): 0.015; Time/step: 0.7 s and total scan time of approximately 1 hr. The XRD pattern indicates the crystallographic structure of the nanoparticles. Strong and sharp diffraction peaks at 2θ values were observed in both cases (ZrO2 - in red; NiO - in black), especially, for NiO with precise peaks - 37, 43.5, 63 etc., while the ZrO2 diffraction Peaks value were 28.5, 31.5, 34.5, 50.5 etc. The peaks are indications of the pure phase formation of the ZrO2 and NiO nanoparticles. The crystallographic phases of the nanoparticles were also identified. Pure ZrO<sup>2</sup> exhibits a tetragonal phase (**Figure 10** (i)), and the pure NiO exhibits a cubic phase (**Figure 10** (ii)), consistent with literature [92, 135].

#### **5.4. Contact angle**

**5.2. Particle size and surface area**

340 Novel Nanomaterials - Synthesis and Applications

**Figure 7.** SEM images of: (a) ZrO<sup>2</sup>

size of the particles. **Figure 8** shows that the ZrO2

in the range of 10–12 nm. The average particle diameter for ZrO<sup>2</sup>

; (b) NiO nanoparticles.

of the ZrO2

value for NiO was ~ 12 nm.

**Figure 8.** Particle size morphology of a) ZrO2

Particle size plays a vital role in the nanoparticle characterization as their physical and chemical properties greatly depend on the particle size. The small particle size of nanoparticles yields important features such as surface area. Nanoparticle size and surface area are interrelated; as the nanoparticle size becomes negligible, the particle surface area increases. Bulk materials as opposed to nanoparticle exhibit larger particle sizes (nanoparticle avarage diameter: <100 nm; microparticle >1 μm) with tons of atoms on the inside of the particle and limited atoms at the surface, whereas, with nanoparticles more atoms are predominantly on the outer surface of the particles. Such high surface area enables the bonding of other materials on the particle surface and lead to the generation of even much stronger materials that promote better interaction with neighboring atoms or ions. Ascertaining the nanoparticles size is essential as it affects particulate materials properties and can act as an approach to determine the quality and performance of these materials. The particle size

and NiO nanoparticles was investigated to obtain more accurate and precise

; b) NiO nanoparticles (<50 nm).

particle size was 21–35 nm and NiO was

~ 28 nm and the average

An understanding of surface chemistry is imperative for evaluating wetting behavior as porous media wetting are influenced by the rock surface morphology, as well as, the chemical compositions. Surface chemistry modifications of materials facilitate short-ranged chemical interactions. This phenomenon is predominantly governed by the surface and interfacial interactions, which act over the scale of molecules, and electrostatic surface forces that determine the extent to which

**Figure 9.** XRD patterns of the ZrO<sup>2</sup> and NiO nanoparticles.

a fluid can wet a surface [48]. Quantification of wettability of solid surfaces was also performed to ascertain the effects of ZrO<sup>2</sup> and NiO nanoparticle on wettability alteration of carbonate rocks. Contact angle tests were conducted at solid-liquid-air interface to ascertain the wetting variances prior and after nano-modifications. Water-advancing and receding contact angles were measured of which the advancing contact angles better defines wettability since its relevant to waterflooding [51]. The understanding of contact angle is complex as it exhibits a dependency on the solid-liquid interaction and the structure of the solid or mineralogy of the rock sample.

angles were measured. **Figures 12** and **13** (SEM) show nano-modified calcites, as compared to

spherical-like shape and more uniformly adsorbed behavior on the calcite surface than NiO, while the NiO exhibits a hexagonal-like shape which is consistent with the earlier observation in Section 4.31. **Figure 15** shows the contact angle measurement as a function of nanoparticle

sure of the calcite to a different environment would change its surface property. The calcite

adsorbed on the calcite surface after exposure to air. Such film thickness can vary between a fraction to numerous fractions of a molecule. However, the level of thickness is dependent on the affinity of the molecules to the substrate and the corresponding distance to the bulk critical point. Moreso, the nano-films on the rock surface may appear thinner than others, which is dependent on the nanoparticle type, and their optical and electrical properties. ZrO<sup>2</sup> nano-films are relatively thicker than those of other nanoparticles owing to its material properties such as large band gap >5ev and high-dielectric constant >20 (Petit and Monot, 2015).

and NiO nanoparticle respectively in air. It is expected that the expo-

and NiO nanofluids, film-like deposits of the nanofluids were

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

nano-layers on the oil-wet calcite surface when

nanoparticle exhibits a

343

http://dx.doi.org/10.5772/intechopen.72267

the fresh calcite without any nano-modification (**Figure 11**). The ZrO<sup>2</sup>

concentration for ZrO2

upon contact with the ZrO2

This may have formed better-adsorbed ZrO<sup>2</sup>

**Figure 11.** SEM image of pure calcite surface before nano-modification.

compared to the NiO nanoparticles.

Prior to the contact angle measurement, calcite substrates were cleaned and aged based on procedure 4.2.2. The nanofluids were prepared using various nanoparticle concentration (0.005–0.05 wt. %) and fixed NaCl brine concentration (7 wt. %) as dispersing agents based on procedure 4.2.2. The samples were immersed in the nanofluids and subsequently contact

**Figure 10.** (a) Crystallographic phases of the ZrO2 nanoparticles exhibiting tetragonal phase. (b). Crystallographic phase of the NiO nanoparticles exhibiting cubic phase.

angles were measured. **Figures 12** and **13** (SEM) show nano-modified calcites, as compared to the fresh calcite without any nano-modification (**Figure 11**). The ZrO<sup>2</sup> nanoparticle exhibits a spherical-like shape and more uniformly adsorbed behavior on the calcite surface than NiO, while the NiO exhibits a hexagonal-like shape which is consistent with the earlier observation in Section 4.31. **Figure 15** shows the contact angle measurement as a function of nanoparticle concentration for ZrO2 and NiO nanoparticle respectively in air. It is expected that the exposure of the calcite to a different environment would change its surface property. The calcite upon contact with the ZrO2 and NiO nanofluids, film-like deposits of the nanofluids were adsorbed on the calcite surface after exposure to air. Such film thickness can vary between a fraction to numerous fractions of a molecule. However, the level of thickness is dependent on the affinity of the molecules to the substrate and the corresponding distance to the bulk critical point. Moreso, the nano-films on the rock surface may appear thinner than others, which is dependent on the nanoparticle type, and their optical and electrical properties. ZrO<sup>2</sup> nano-films are relatively thicker than those of other nanoparticles owing to its material properties such as large band gap >5ev and high-dielectric constant >20 (Petit and Monot, 2015). This may have formed better-adsorbed ZrO<sup>2</sup> nano-layers on the oil-wet calcite surface when compared to the NiO nanoparticles.

a fluid can wet a surface [48]. Quantification of wettability of solid surfaces was also performed

Contact angle tests were conducted at solid-liquid-air interface to ascertain the wetting variances prior and after nano-modifications. Water-advancing and receding contact angles were measured of which the advancing contact angles better defines wettability since its relevant to waterflooding [51]. The understanding of contact angle is complex as it exhibits a dependency on the solid-liquid interaction and the structure of the solid or mineralogy of the rock sample. Prior to the contact angle measurement, calcite substrates were cleaned and aged based on procedure 4.2.2. The nanofluids were prepared using various nanoparticle concentration (0.005–0.05 wt. %) and fixed NaCl brine concentration (7 wt. %) as dispersing agents based on procedure 4.2.2. The samples were immersed in the nanofluids and subsequently contact

and NiO nanoparticle on wettability alteration of carbonate rocks.

nanoparticles exhibiting tetragonal phase. (b). Crystallographic phase

to ascertain the effects of ZrO<sup>2</sup>

342 Novel Nanomaterials - Synthesis and Applications

**Figure 10.** (a) Crystallographic phases of the ZrO2

of the NiO nanoparticles exhibiting cubic phase.

**Figure 11.** SEM image of pure calcite surface before nano-modification.

contact. The nanoparticles in suspension act as a coating mechanism by self-structuring into layered NPs and changes the entropy of the system. The particles hydrophilic nature facilitates their adsorption on the rock surface in form of a wedge film which in turn displaces the oil on the surface of the rock, yielding a hydrophilic state. Ideally, if wettability is preferentially altered to favorable water-wet condition and the IFT is ultralow, the forces that retain oil in a fractured reservoir can be overcome as capillarity is diminished through the ultralow IFTs.

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

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345

**Figure 13.** SEM image of calcite surface after NiO nano-modification.

**Figure 12.** SEM image of calcite surface after ZrO<sup>2</sup> nano-modification.

As the dispensed water droplet comes in contact with the surface of the nano-coated calcite, the contact angle decreases owing to the presence of adsorbed nano-layers. This behavior is attributed to the favorable interaction of the nanoparticles with the dispersing fluid (NaCl brine) and high chemical affinity to the calcite. Such solid-liquid interaction at the interface is mainly due to electrostatic interactions. The presence of the nanoparticle increased the surface activity of the brine (NaCl), thereby modifying the calcite surface wetting propensity upon contact. The nanoparticles in suspension act as a coating mechanism by self-structuring into layered NPs and changes the entropy of the system. The particles hydrophilic nature facilitates their adsorption on the rock surface in form of a wedge film which in turn displaces the oil on the surface of the rock, yielding a hydrophilic state. Ideally, if wettability is preferentially altered to favorable water-wet condition and the IFT is ultralow, the forces that retain oil in a fractured reservoir can be overcome as capillarity is diminished through the ultralow IFTs.

**Figure 13.** SEM image of calcite surface after NiO nano-modification.

As the dispensed water droplet comes in contact with the surface of the nano-coated calcite, the contact angle decreases owing to the presence of adsorbed nano-layers. This behavior is attributed to the favorable interaction of the nanoparticles with the dispersing fluid (NaCl brine) and high chemical affinity to the calcite. Such solid-liquid interaction at the interface is mainly due to electrostatic interactions. The presence of the nanoparticle increased the surface activity of the brine (NaCl), thereby modifying the calcite surface wetting propensity upon

nano-modification.

**Figure 12.** SEM image of calcite surface after ZrO<sup>2</sup>

344 Novel Nanomaterials - Synthesis and Applications

**Figure 14** shows the image representation of the transition phase toward water-wet in air from 88° θ<sup>a</sup> to 48° θ<sup>a</sup> (NiO/NaCl) and 38° θ<sup>a</sup> (ZrO2 /NaCl). A decrease in contact angle was observed for all the systems tested with an increase in the nanoparticle concentration (**Figure 15**) consistent with literature [36–38, 136–139]. Calcite substrates coated with ZrO<sup>2</sup> /NaCl fluids demonstrated better wetting propensities than the NiO/NaCl system. The efficiency of the systems is due to efficient surface adsorption of the particles on the pore walls of the rock, which invariably rendered the rock surface sufficiently water wet upon contact.

**Figure 14.** Contact angle images showing variation with increase in nanoparticle concentration (a) unmodified (high θ-indicating an intermediate-wet state—88° θ<sup>a</sup> ); (B, C) nano-modified—(B) NiO/NaCl modified (NiO concentration—0.005–0.05); (C) ZrO<sup>2</sup> /NaCl nano-modified (ZrO<sup>2</sup> concentration—0.005-0.05) (B and C indicates low θ which represents strong interaction with the rock surface, and inclination to wet; I–IV); see graphical representation for θ values.

**6. Conclusions**

(< 50 nm) and different shape patterns. The ZrO<sup>2</sup>

ZrO2

The interfacial behavior of nickel oxide and zirconium oxide nanoparticles at solid-liquid interface was studied on their propensity to alter oil-wet surfaces toward water-wet conditions. The

**Figure 15.** Receding and advancing water contact angles in air (1 h exposure time) (a) NiO; (b) ZrO2

ticles while the NiO displayed hexagonal-like shaped particles (**Figures 7**, **12** and **13**). The XRD crystallographic structure and phase identification shows the tetragonal phase of the ZrO<sup>2</sup>

 and NiO nanoparticles exhibited very different structural and morphological features, as well as crystallinity phases. The nanoparticles exhibited particles size in ranges below 50 nm

nanoparticles are sphere-like shaped par-

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

347

,

at ambient condition.

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration http://dx.doi.org/10.5772/intechopen.72267 347

**Figure 15.** Receding and advancing water contact angles in air (1 h exposure time) (a) NiO; (b) ZrO2 at ambient condition.

#### **6. Conclusions**

**Figure 14** shows the image representation of the transition phase toward water-wet in air from

for all the systems tested with an increase in the nanoparticle concentration (**Figure 15**) consis-

strated better wetting propensities than the NiO/NaCl system. The efficiency of the systems is due to efficient surface adsorption of the particles on the pore walls of the rock, which invari-

**Figure 14.** Contact angle images showing variation with increase in nanoparticle concentration (a) unmodified

which represents strong interaction with the rock surface, and inclination to wet; I–IV); see graphical representation for

/NaCl nano-modified (ZrO<sup>2</sup>

); (B, C) nano-modified—(B) NiO/NaCl modified (NiO

concentration—0.005-0.05) (B and C indicates low θ

(high θ-indicating an intermediate-wet state—88° θ<sup>a</sup>

concentration—0.005–0.05); (C) ZrO<sup>2</sup>

θ values.

/NaCl). A decrease in contact angle was observed

/NaCl fluids demon-

(ZrO2

tent with literature [36–38, 136–139]. Calcite substrates coated with ZrO<sup>2</sup>

ably rendered the rock surface sufficiently water wet upon contact.

88° θ<sup>a</sup>

to 48° θ<sup>a</sup>

346 Novel Nanomaterials - Synthesis and Applications

(NiO/NaCl) and 38° θ<sup>a</sup>

The interfacial behavior of nickel oxide and zirconium oxide nanoparticles at solid-liquid interface was studied on their propensity to alter oil-wet surfaces toward water-wet conditions. The ZrO2 and NiO nanoparticles exhibited very different structural and morphological features, as well as crystallinity phases. The nanoparticles exhibited particles size in ranges below 50 nm (< 50 nm) and different shape patterns. The ZrO<sup>2</sup> nanoparticles are sphere-like shaped particles while the NiO displayed hexagonal-like shaped particles (**Figures 7**, **12** and **13**). The XRD crystallographic structure and phase identification shows the tetragonal phase of the ZrO<sup>2</sup> , whereas, the NiO nanoparticle has a cubic phase orientation. The nanoparticles also displayed favorable adsorption behavior on the calcite surface as evident in the SEM images, which facilitated the wetting change quantified by contact angle measurement, however, the ZrO<sup>2</sup> based systems exhibited more uniform surface distribution and better wetting than NiO. Thus, nanoparticles are considered efficient modifiers for wettability alteration of surfaces toward a suitable hydrophilic condition.

[8] Yu W, France DM, Routbort JL, Choi SU. Review and comparison of nanofluid thermal conductivity and heat transfer enhancements. Heat Transfer Engineering. 2008;**29**(5):432-460 [9] Ramakoteswaa RN, Gahane L, Ranganayakulu SV. Synthesis, applications and chal-

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

349

[10] Biswas P, Wu CY. Control of toxic metal emissions from combustors using sorbents: A review. Journal of the Air & Waste Management Association. 1998;**48**(2):113-127

[11] Serrano E, Rus G, Garcia-Martinez J. Nanotechnology for sustainable energy. Renewable

[12] Khalil M, Jan BM, Tong CW, Berawi MA. Advanced Nanomaterials in oil and gas indus-

[13] Jun YW, Choi JS, Cheon J. Heterostructured magnetic nanoparticles: Their versatility and high-performance capabilities. Chemical Communications. 2007;**12**:1203-1214 [14] Pastrana-Martínez LM, Pereira N, Lima R, Faria JL, Gomes HT, Silva AMT. Degradation of diphenhydramine by photo-fenton using magnetically recoverable iron oxide

[15] Avendano C, Lee SS, Escalera G, Colvin V. Magnetic characterization of nanoparticles designed for use as contrast agents for downhole measurements. In: SPE 157123 presented at the SPE international oilfield nanotechnology conference and exhibition, Noordwijk,

[16] Morrow L, Potter DK, Barron AR. Detection of magnetic nanoparticles against proppant and shale reservoir rocks. Journal of Experimental Nanoscience. 2015;**10**(13):1028-1041

[17] Hyne JB, Greidanus JW, Tyrer JD, Verona D, Rizek C, Clark PD, Clarke RA, Koo J. Aquathermolysis of heavy oils. The Second International Conference on Heavy Crude and Tar

[18] White RJ, Luque R, Budarin VL, Clark JH, Macquarrie DJ. Supported metal nanoparticles on porous materials, methods and applications. Chemical Society Reviews.

[19] Fedele L, Colla L, Bobbo S, Barison S, Agresti F. Experimental stability analysis of differ-

[21] Tjong SC. Novel nanoparticle-reinforced metal matrix composites with enhanced

[22] Yang Y, Lan J, Li X. Study on bulk aluminum matrix nano-composite fabricated by ultrasonic dispersion of nano-sized SiC particles in molten aluminum alloy. Materials Science

mechanical properties. Advanced Engineering Materials. 2007;**9**(8):639-652

oil recovery of carbonate reservoirs. Journal of Petroleum Exploration and Production

nanoparticles on enhanced

ent water-based nanofluids. Nanoscale Research Letters. 2011;**6**(1):300

[20] Roustaei A, Bagherzadeh H. Experimental investigation of SiO<sup>2</sup>

try: Design, application, and challenges. Applied Energy. 2017;**191**:287-310

nanoparticles as catalyst. Chemical Engineering Journal. 2015;**261**:45-52

lenges of nanofluids-review. IOSR Journal of Applied Physics. 2014:21-28

and Sustainable Energy Reviews. 2009;**13**:2373-2384

The Netherlands. 12-14 June 2012

2009;**38**(2):481-494

Technology. 2015;**5**(1):27-33

and Engineering A. 2004;**380**(1):378-383

Sands, in Caracas, Venezuela, Feb 7-17, 1982

## **Author details**

Lezorgia Nekabari Nwidee<sup>1</sup> \*, Ahmed Barifcani1,2, Mohammad Sarmadivaleh<sup>1</sup> and Stefan Iglauer<sup>1</sup>

\*Address all correspondence to: l.nwidee@postgrad.curtin.edu.au

1 Department of Petroleum Engineering, Curtin University, Perth, Western Australia, Australia

2 Department of Chemical Engineering, Curtin University, Perth, Western Australia, Australia

## **References**


[8] Yu W, France DM, Routbort JL, Choi SU. Review and comparison of nanofluid thermal conductivity and heat transfer enhancements. Heat Transfer Engineering. 2008;**29**(5):432-460

whereas, the NiO nanoparticle has a cubic phase orientation. The nanoparticles also displayed favorable adsorption behavior on the calcite surface as evident in the SEM images, which facilitated the wetting change quantified by contact angle measurement, however, the ZrO<sup>2</sup> based systems exhibited more uniform surface distribution and better wetting than NiO. Thus, nanoparticles are considered efficient modifiers for wettability alteration of surfaces toward a

\*, Ahmed Barifcani1,2, Mohammad Sarmadivaleh<sup>1</sup>

and

suitable hydrophilic condition.

348 Novel Nanomaterials - Synthesis and Applications

Lezorgia Nekabari Nwidee<sup>1</sup>

\*Address all correspondence to: l.nwidee@postgrad.curtin.edu.au

1 Department of Petroleum Engineering, Curtin University, Perth, Western Australia,

2 Department of Chemical Engineering, Curtin University, Perth, Western Australia,

[1] Campelo JM, Luna D, Luque R, Marinas JM, Romero AA. Sustainable preparation of supported metal nanoparticles and their applications in catalysis. ChemSusChem. 2009;

[2] Colomban P. The use of metal nanoparticles to produce yellow, red and iridescent colour, from bronze age to present times in lustre pottery and glass: Solid state chemistry, spectroscopy and nanostructure. Journal of Nano Research. 2009;**8**:109-132 Trans

[3] Heiligtag FJ, Niederberger M. The fascinating world of nanoparticle research. Materials

[4] Kaminsky R, Radke CJ. Asphaltenes, water films and wettability reversal. Society of

[5] Kamyshny AS, Magdassi S. Aqueous dispersions of metallic nanoparticles. Colloidal

[6] Edmunds N, Chhina H. Economic optimum operating pressure for SAGD projects in

[7] Nanotek. Pioneering Expansion in the world of Nanotechnology. 19th International Conference on Nanotechnology and Expo. Atlanta, Georgia, USA. 2017. Retrieved on 15

Alberta. Journal of Canadian Petroleum Technology. 2001;**40**(12):13-17

April, 2017 from http://nanotechnologyexpo.conferenceseries.com/

**Author details**

Stefan Iglauer<sup>1</sup>

Australia

Australia

**References**

**2**(1):18-45

Tech Publications

Today. 2013;**16**(7):262-271

Interfacial Aspects. 2010:747-778

Petroleum Engineers Journal. 1997;**2**(4):458-493


[23] Mao H, Qiu Z, Shen Z, Huang W. Hydrophobic associated polymer based silica nanoparticles composite with core-shell structure as a filtrate reducer for drilling fluid at utrahigh temperature. Journal of Petroleum Science and Engineering. 2015;**129**:1-14

[38] Nwidee LN, Al-Anssari S, Barifcani A, Sarmadivaleh M, Lebedev M, Iglauer S.Wettability alteration of oil-wet limestone using surfactant-nanoparticle formulation. Journal of

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

351

[39] Nwidee LN, Theophilus S, Barifcani A, Sarmadivaleh M, Iglauer S. EOR processes, opportunities and technological advancements. In: Chemical Enhanced Oil Recovery

[40] Wang XQ, Mujumdar AS. A review on nanofluids-part I: Theoretical and numerical investigations. Brazilian Journal of Chemical Engineering. 2008;**25**(4):613-630

[41] Yang Y, Lan J, Li X. Study on bulk aluminum matrix nano-composite fabricated by ultrasonic dispersion of nano-sized SiC particles in molten aluminum alloy. Materials Science

[42] Guo D, Xie G, Luo J. Mechanical properties of nanoparticles: Basics and applications.

[43] De Gennes PG. Wetting: Statistics and dynamics. Reviews of Modern Physics. 1985;

[44] Mohammed M, Babadagli T. Wettability alteration: A comprehensive review of materials/methods and testing the selected ones on heavy-oil containing oil-wet systems.

[45] Bertrand E, Bonn D, Broseta D, Dobbs H, Indekeu JO, Meunier J, Ragil K, Shahidzadeh N. Wetting of alkanes on water. Journal of Petroleum Science and Engineering. 2002;

[47] Craig FF. The Reservoir Engineering Aspects of Waterflooding. SPE, Richardson, Texas:

[48] Bonn D, Eggers J, Indekeu J, Meunier J, Rolley E. Wetting and spreading. Reviews of

[49] Anderson WG. Wettability literature survey - part 1: Rock/oil/brine interactions and the effects of core handling on wettability. Journal of Petroleum Techology. 1986;

[50] Anderson WG. Wettability literature survey part 2: Wettability measurement. Journal of

[51] Anderson WG. Wettability literature survey-part 3: The effects of wettability on the electrical properties of porous media. Journal of Petroleum Technology. 1986;**38**(12):1371-1378

[52] Morrow NR. Wettability and its effect on oil recovery. Journal of Petroleum Technology.

[53] Abdallah W, Buckley J, Carnegie A, Edwards J, Herold B, Fordham E, Graue A, Habashy T, Seleznev N, Signer C, Hussain H. Fundamentals of wettability. Oilfield Review. 2007:44-61

Colloid and Interface Science. 2017b;**504**:334-345

(cEOR)-a Practical Overview. InTech; 2016

and Engineering A. 2004;**380**(1):378-383

**57**(3):827-863

**33**(1):217-222

Monograph Series; 1971

**38**(10):1125-1144

1990;**42**(12):1-476

Modern Physics. 2009;**81**:739-805

Petroleum Techology. 1986;**38**:1246-1262

Journal of Physics D: Applied Physics. 2014;**47**(1):013001

Advances in Colloid and Interface Science. 2015;**220**:54-77

[46] Myers D. Surfaces, Interfaces and Colloids. Wiley-Vch: New York; 1990


[38] Nwidee LN, Al-Anssari S, Barifcani A, Sarmadivaleh M, Lebedev M, Iglauer S.Wettability alteration of oil-wet limestone using surfactant-nanoparticle formulation. Journal of Colloid and Interface Science. 2017b;**504**:334-345

[23] Mao H, Qiu Z, Shen Z, Huang W. Hydrophobic associated polymer based silica nanoparticles composite with core-shell structure as a filtrate reducer for drilling fluid at utra-

[24] Salem RAM, Hannora AEA. Comparative investigation of nanoparticle effects for improved oil recovery-experimental work. In: Proceedings of the SPE Kuwait Oil and

[25] Metin CO, Baran JR, Nguyen QP. Adsorption of surface functionalized silica nanoparticles onto mineral surfaces and decane/water interface. Journal of Nanoparticle Research.

[26] Hendraningrat L, Torsæter O. Metal oxide-based nanoparticles: Revealing their potential to enhance oil recovery in different wettability systems. Applied Nanoscience.

[27] Ahmadi MA, Shadizadeh SR. Induced effect of adding nano silica on adsorption of a natural surfactant onto sandstone rock: Experimental and theoretical study. Journal of

[28] Bayat AE, Junin R, Shamshirband S, Chong WT. Transport and retention of engineered

[29] Saravanan P, Gopalan R, Chandrasekaran V. Synthesis and characterization of nanoma-

[30] Rudyak VY. Viscosity of nanofluids-why it is not described by the classical theories.

[31] Choi S. Enhancing thermal conductivity of fluids with nanoparticles. In: Siginer DA, Wang HP, editors. Developments Applications of Non-Newtonian Flows. New York: 231,

[32] Yu W, Xie H. A review on nanofluids: Preparation, stability mechanisms and applica-

[33] Al-Anssari S, Barifcani A, Wang S, Maxim L, Iglauer S. Wettability alteration of oil-wet carbonate by silica nanofluid. Journal of Colloid and Interface Science. 2016;**461**:435-442

[34] Al-Anssari S, Wang S, Barifcani A, Iglauer S. Oil-water interfacial tensions of silica

[35] Keblinski P, Prasher R, Eapen J. Thermal conductance of nanofluids: Is the controversy

[36] Nwidee LN, Al-Anssari S, Barifcani A, Sarmadivaleh M, Iglauer S. Nanofluids for enhanced oil recovery processes: wettability alteration using zirconium oxide. Offshore Technology Conference (OTC-26573-MS). Kuala Lumpur, Malaysia, 22-25 March 2016a

[37] Nwidee LN, Al-Anssari S, Barifcani A, Sarmadivaleh M, Lebedev M, Iglauer S. Nanoparticles influence on wetting behaviour of fractured limestone formation. Journal of

nanoparticle-surfactant formulations. Tenside, Surfactants, Detergents;**54**:6

over? Journal of Nanoparticle Research. 2008;**10**(7):1089-1097

Petroleum Science and Engineering. 2017a;**149**:782-788

nanoparticles through various sedimentary rocks. Scientific Reports.

high temperature. Journal of Petroleum Science and Engineering. 2015;**129**:1-14

Gas Show and Conference, Mishref, Kuwait, 11-14 October 2015

Petroleum Science and Engineering. 2013;**112**:239-247

terials. Defence Science Journal. 2008;**58**(4):504-516

Advances in Nanoparticles. 2013;**2**(3):266-279

tions. Journal of Nanomaterials. 2012:1-17

2012;**14**(11):1246

350 Novel Nanomaterials - Synthesis and Applications

2015;**5**(2):181-199

, and SiO<sup>2</sup>

ASME; 1995. pp. 99-105

Al<sup>2</sup> O3 , TiO2

2015;**5**:14264


[54] Nutting PG. Some physical and chemical properties of reservoir rocks bearing on the accumulations and discharge of oil. In: Wrather WE, Lahee FH, editors. Problems of Petroleum Geology. American Association of Petroleum Geologists; 1934. pp. 825-832

[69] Lord DL, Buckley JS. An AFM study of the morphological features that affect wetting at crude oil-water-mica interfaces. Colloids and Surfaces A: Physicochemical and

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

353

[70] Acevedo S, Escobar G, Ranaudo MA, Piñate J, Amorı'n A, Dı'az M, Silva P. Observations about the structure and dispersion of petroleum asphaltenes aggregates obtained from

[71] González G, Moreira MB. The wettability of mineral surfaces containing adsorbed

[72] Andersen SI, Christensen SD. The critical micelle concentration of asphaltenes as mea-

[73] Kaminsky R, Radke CJ. Asphaltenes, water films and wettability reversal. Society of

[74] Liu L, Buckley JS. Alteration of wetting of mica surfaces. Journal of Petroleum Science

[75] Standal S, Haavik J, Blokhus AM, Skauge A. Effect of polar organic components on wettability as studied by adsorption and contact angles. Journal of Petroleum Science and

[76] Donaldson EC, Thomas RD, Lorenz PB. Wettability determination and its effects on recovery efficiency. Society of Petroleum Engineering Journal. 1969;**9**(1):13-20

[77] Zhang P, Austad T. Wettability and oil recovery from carbonates: Effects of temperature and potential determining ions. Colloids and Surfaces A: Physicochemical and

[78] Standnes DC, Austad T. Nontoxic low-cost amines as wettability alteration Chemicals in Carbonates. Journal of Petroleum Science and Engineering. 2003;**39**(3):431-438

[79] Standnes DC, Austad T. Wettability alteration in chalk: 1. Preparation of core material and oil properties. Journal of Petroleum Science and Engineering. 2000;**28**(3):111-121

[80] Standnes DC, Austad T. Wettability alteration in chalk: 2. Mechanism for wettability alteration from oil-wet to water-wet using surfactants. Journal of Petroleum Science and

[81] Standnes DC, Austad T. Wettability alteration in carbonates: Interaction between cationic surfactant and carboxylates as a key factor in wettability alteration from oil-wet to water-wet conditions. Colloids and Surfaces A: Physicochemical and Engineering

[82] Standnes DC, Nogaret LA, Chen HL, Austad T. An evaluation of spontaneous imbibition of water into oil-wet carbonate reservoir cores using a nonionic and a cationic surfactant.

dialysis fractionation and characterization. Energy & Fuels. 1997;**11**(4):774-778

Engineering Aspects. 2002;**206**(1):531-546

asphaltene. Colloids and Surfaces. 1991;**58**(3):293-302

sured by calorimetry. Energy & Fuels. 2000;**14**(I1):38-42

Petroleum Engineers Journal. 1997;**2**(4):458-493

and Engineering. 1999;**24**(2):75-83

Engineering. 1999;**24**(2-4):131-144

Engineering. 2000;**28**(3):123-143

Aspects. 2003;**216**(1):243-259

Energy and Fuels. 2002;**16**(6):1557-1564

Engineering Aspects. 2006;**279**(1):179-187


[69] Lord DL, Buckley JS. An AFM study of the morphological features that affect wetting at crude oil-water-mica interfaces. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2002;**206**(1):531-546

[54] Nutting PG. Some physical and chemical properties of reservoir rocks bearing on the accumulations and discharge of oil. In: Wrather WE, Lahee FH, editors. Problems of Petroleum Geology. American Association of Petroleum Geologists; 1934. pp. 825-832

[55] Benner FC, Bartel FE. The effect of polar impurities upon capillary and surface phenomena in petroleum production. Drilling and production practice. American Petroleum

[56] Moore CH. Carbonate Reservoirs Porosity Evolution and Diagenesis in a Sequence

[58] Lebedev M, Wilson ME, Mikhaltsevitch V. An experimental study of solid matrix weakening in water-saturated Savonnières limestone. Geophysical Prospecting. 2014;

[59] Treiber LE, Archer DL, Owens WW. A laboratory evaluation of the wettability of fifty oil-producing reservoirs. Society of Petroleum Engineers Journal. 1972;**12**(6):531-540 [60] Chilingar GV, Yen TF. Some notes on wettability and relative permeabilities of carbonate

[61] Buckley JS, Liu Y, Monsterleet S. Mechanisms of wetting alteration by crude oils. Society

[62] Thomas S. Enhanced oil recovery-an overview. Oil & Gas Science and Technology.

[63] Babadagli T. Scaling of co-current and counter-current capillary imbibition for surfactant and polymer injection in naturally fractured reservoirs. SPE/AAPG western regional

[64] Cheraghian G, Hemmati M, Masihi M, Bazgir S. An experimental investigation of the enhanced oil recovery and improved performance of drilling fluids using titanium dioxide and fumed silica nanoparticles. Journal of Nanostructure in Chemistry. 2013;**3**(1):1-19

[65] Delshad M, Najafabadi NF, Anderson G, Pope GA, Sepehrnoori K. Modeling wettability alteration by surfactants in naturally fractured reservoirs. SPE Reservoir Evaluation &

[66] Buckley JS, Liu Y, Monsterleet S. Mechanisms of wetting alteration by crude oils. Society

[67] Yu L, Buckley JS. Evolution of wetting alteration by adsorption from crude oil. Society of

[68] Tong Z, Xie X, Morrow NR. Crude oil composition and the ability of mixed wettability in sandstones. SCA International Symposium of the Society of Core Analysts, Monterey,

[57] Tucker ME, Wright VP. Carbonate sedimentology. John Wiley and Sons; 2009

Institute, New York, New York ,1 January 1941

**62**(6):1253-1265

352 Novel Nanomaterials - Synthesis and Applications

2008;**63**(1):9-19

Stratigraphic Framework. Amsterdam: Elsevier; 2001

reservoir rocks II. Journal of Energy Sources. 1983;**7**(1):67-75

of Petroleum Engineering Journal. 1998;**3**(01):54-61

meeting, Long Beach, California, 19-22 June 2000

of Petroleum Engineering Journal. 1998;**3**(01):54-61

Petroleum Engineers Formation Evaluation. 1997;**12**(01):5-12

Engineering. 2009;**12**(3):361-370

CA, USA, 30 September 2002


[83] Buckley JS, Lord DL. Wettability and morphology of mica surfaces after exposure to crude oil. Journal of Petroleum Science and Engineering. 2003;**39**(3):261-273

[98] Srinivasan V, Weidner JW.An electrochemical route for making porous nickel oxide electrochemical capacitors. Journal of the Electrochemical Society. 1997;**144**(8):L210-L213

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

355

[99] Liu KC, Anderson MA. Porous nickel oxide/nickel films for electrochemical capacitors.

[100] Chakrabarty S, Chatterjee K. Synthesis and characterization of nano-dimensional nickelous oxide (NiO) semiconductor. Journal of Physical Science. 2009;**13**:245-250

[101] Wu Y, He Y, Wu T, Chen T, Weng W, Wan H. Influence of some parameters on the synthesis of nanosized NiO material by modified sol-gel method. Materials Letters. 2007;

[102] Thota S, Kumar J. Sol-gel synthesis and anomalous magnetic behaviour of NiO nanopar-

[103] Hotovy I, Huran J, Spiess L, Romanus H, Buc D, Kosiba R. NiO-based nanostructured thin films with Pt surface modification for gas detection. Thin Solid Films. 2006;**515**(2):

[104] Min KC, Kim M, You YH, Lee SS, Lee YK, Chung TM, Kim CG, Hwang JH, An KS, Lee NS, Kim Y. NiO thin films by MOCVD of Ni (dmamb) 2 and their resistance switching phe-

[105] Tao D, Wei F. New procedure towards size-homogeneous and well-dispersed nickel oxide

[106] Dooley KM, Chen SY, Ross JRH. Stable nickel-containing catalysts for the oxidative

[107] Yang HX, Dong QF, Hu XH, Ai XP, Li SX. Preparation and characterization of LiNiO<sup>2</sup>

[108] Miller EL, Rocheleau RE. Electrochemical behavior of reactively sputtered iron-doped nickel oxide. Journal of the Electrochemical Society. 1997;**144**(9):3072-3077

[109] Ichiyanagi Y, Wakabayashi N, Yamazaki J, Yamada S, Kimishima Y, Komatsu E, Tajima H. Magnetic properties of nio nanoparticles. Physica B: Condensed Matter.

[110] Venkataraj S, Kappertz O, Weis H, Drese R, Jayavel R, Wuttig M. Structural and optical properties of thin zirconium oxide films prepared by reactive direct current magnetron

[111] Gao P, Meng LJ, dos Santos MP, Teixeira V, Andritschky M. Characterisation of ZrO<sup>2</sup>

[112] Petit M, Monot J. Functionalization of Zirconium Oxide Surfaces. Chemistry of Organo-Hybrids: Synthesis and Characterization of Functional Nano-Objects. 2015. pp. 168-199

O. Journal of Power Sources. 1999;**79**(2):256-261

concentrations in the sputtering

ticles. Journal of Physics and Chemistry of Solids. 2007;**68**(10):1951-1964

nomena. Surface and Coatings Technology. 2007;**201**(22):9252-9255

nanoparticles of 30nm. Materials Letters. 2004;**58**(25):3226-3228

coupling of methane. Journal of Catalysis. 1994;**145**(2):402-408

sputtering. Journal of Applied Physics. 2002;**92**(7):3599-3607

films prepared by rf reactive sputtering at different O<sup>2</sup>

gases. Vacuum. 2000;**56**(2):143-148

and LiOH·H<sup>2</sup>

Journal of the Electrochemical Society. 1996;**143**(1):124-130

**61**(14):3174-3178

synthesized from Ni (OH)<sup>2</sup>

2003;**329**:862-863

658-661


[98] Srinivasan V, Weidner JW.An electrochemical route for making porous nickel oxide electrochemical capacitors. Journal of the Electrochemical Society. 1997;**144**(8):L210-L213

[83] Buckley JS, Lord DL. Wettability and morphology of mica surfaces after exposure to

[84] Zhang DL, Liu S, Puerto M, Miller CA, Hirasaki GJ. Wettability alteration and spontaneous imbibition in oil-wet carbonate formations. Journal of Petroleum Science and

[85] Seiedi O, Rahbar M, Nabipour M, Emadi MA, Ghatee MH, Ayatollahi S. Atomic force microscopy (AFM) investigation on the surfactant wettability alteration mechanism of

[86] Kathel P, Mohanty KK. Wettability alteration in a tight oil reservoir. Energy and Fuels.

[87] Bera A, Ojha K, Kumar T, Mandal A. Mechanistic study of wettability alteration of quartz surface induced by nonionic surfactants and interaction between crude oil and quartz in

[88] Hou BF, Wang YF, Huang Y. Mechanistic study of wettability alteration of oil-wet sandstone surface using different surfactants. Applied Surface Science. 2015;**330**:56-64 [89] Hou BF, Wang YF, Huang Y. Relationship between reservoir wettability and oil recovery by waterflooding. In: In Advances in Energy Science and Equipment Engineering,

[90] Kamal H, Elmaghraby EK, Ali SA, Abdel-Hady K. Characterization of nickel oxide films deposited at different substrate temperatures using spray pyrolysis. Journal of Crystal

[91] Choi JM, Im S. Ultraviolet enhanced Si-photodetector using p-NiO films. Applied

[92] Kunz AB. Electronic structure of NiO. Journal of Physics C: Solid State Physics. 1981;

[93] Adler D, Feinleib J. Electrical and optical properties of narrow-band materials. Physical

[94] Irwin MD, Buchholz DB, Hains AW, Chang RP, Marks TJ. P-type semiconducting nickel oxide as an efficiency-enhancing anode interfacial layer in polymer bulk-heterojunction solar cells. Proceedings of the National Academy of Sciences. 2008;**105**(8):2783-2787 [95] Sato H, Minami T, Takata S, Yamada T. Transparent conducting p-type NiO thin films

[96] Bahadur J, Sen D, Mazumder S, Ramanathan S. Effect of heat treatment on pore structure in nano-crystalline NiO: A small angle neutron scattering study. Journal of Solid State

[97] He J, Lindström H, Hagfeldt A, Lindquist SE. Dye-sensitized nanostructured p-type nickel oxide film as a photocathode for a solar cell. The Journal of Physical Chemistry B.

prepared by magnetron sputtering. Thin Solid Films. 1993;**236**(1):27-31

the presence of sodium chloride salt. Energy and Fuels. 2012;**26**(6):3634-3643

Edited by Zhou, Patty and Chen. London: Taylor Francis Group; 2015

crude oil. Journal of Petroleum Science and Engineering. 2003;**39**(3):261-273

aged mica mineral surfaces. Energy and Fuels. 2010;**25**(1):183-188

Engineering. 2006;**52**(1):213-226

354 Novel Nanomaterials - Synthesis and Applications

2013;**27**(11):6460-6468

Growth. 2004;**262**(1):424-434

Review B. 1970;**2**(8):3112

**14**(16):L455

Surface Science. 2005;**244**(1):435-438

Chemistry. 2008;**181**(5):1227-1235

1999;**103**(42):8940-8943


[113] Balaram N, Reddy MSP, Reddy VR, Park C. Effects of high-k zirconium oxide (ZrO<sup>2</sup> ) interlayer on the electrical and transport properties of au/n-type InP Schottky diode. Thin Solid Films. 2016;**619**:231-238

[128] Ingham B. X-ray scattering characterisation of nanoparticles. Crystallography Reviews.

Nanofluids as Novel Alternative Smart Fluids for Reservoir Wettability Alteration

http://dx.doi.org/10.5772/intechopen.72267

357

[129] Winkler K, Paszewski M, Kalwarczyk T, Kalwarczyk E, Wojciechowski T, Gorecka E, Pociecha D, Holyst R, Fialkowski M. Ionic strength-controlled deposition of charged nanoparticles on a solid substrate. The Journal of Physical Chemistry C. 2011;**115**(39):

[130] Nikolov A, Kondiparty K, Wasan D. Nanoparticle self-structuring in a nanofluid film

[131] Ershadi M, Alaei M, Rashidi A, Ramazani A, Khosravani S. Carbonate and sandstone reservoirs wettability improvement without using surfactants for chemical enhanced

[132] Eshed M, Pol S, Gedanken A, Balasubramanian M. Zirconium nanoparticles prepared by the reduction of zirconium oxide using the rapet method. Beilstein Journal of

[133] Son HA, Yoon KY, Lee GJ, Cho JW, Choi SK, Kim JW, Im KC, Kim HT, Lee KS, Sung WM. The potential applications in oil recovery with silica nanoparticle and polyvinyl alcohol stabilized emulsion. Journal of Petroleum Science and Engineering. 2015;**126**:152-161

[134] Zargartalebi M, Kharrat R, Barati N. Enhancement of surfactant flooding performance

[135] Mercera PDL, Van Ommen JG, Doesburg EBM, Burggraaf AJ, Roes JRH. Stabilized tetragonal zirconium oxide as a support for catalysts evolution of the texture and struc-

[136] Li YV, Cathles LM. Retention of silica nanoparticles on calcium carbonate sands immersed in electrolyte solutions. Journal of Colloid and Interface Science. 2014;**436**:1-8

[137] Zhang T, Murphy M, Yu H, Bagaria H, Nielson B, Bielawski C, Johnston K, Huh C, Bryant S. Investigation of nanoparticle adsorption during transport in porous media. SPE Annual Technical Exhibition, New Orleans, Louisiana, 30 September-2 October. 2013

[138] Ju B, Fan T, Li Z. Improving water injectivity and enhancing oil recovery by wettability control using nanopowders. Journal of Petroleum Science and Engineering.

[139] Maghzi A, Mohammadi S, Ghazanfari MH, Kharrat R, Masihi M. Monitoring wettability alteration by silica nanoparticles during water flooding to heavy oils in five-spot systems: A pore-level investigation. Experimental Thermal and Fluid Science. 2012;**40**:168-176

ture on calcination in static air. Applied Catalysis. 1991;**78**(1):79-96

spreading on a solid surface. Langmuir. 2010;**26**(11):7665-7670

oil recovery (C-EOR). Fuel. 2015;**153**:408-415

by the use of silica nanoparticles. Fuel. 2015;**143**:21-27

Nanotechnology. 2011;**2**(1):198-203

2015;**21**(4):229-303

19096-19103

2012;**86**:206-216


[128] Ingham B. X-ray scattering characterisation of nanoparticles. Crystallography Reviews. 2015;**21**(4):229-303

[113] Balaram N, Reddy MSP, Reddy VR, Park C. Effects of high-k zirconium oxide (ZrO<sup>2</sup>

. Journal of Applied Physics. 2005;**98**(3):033506

[116] Gopalan R, Chang CH, Lin YS. Thermal stability improvement on pore and phase structure of sol-gel derived zirconia. Journal of Materials Science. 1995;**30**(12):3075-3081

[118] Piconi C, Maccauro G. Zirconia as a ceramic biomaterial. Biomaterials. 1999;**20**(1):1-25 [119] Muhammad S, Hussain ST, Waseem M, Naeem A, Hussain J, Jan MT. Surface charge properties of zirconium dioxide. Iranian Journal of Science and Technology. 2012;

[120] Manicone PF, Iommetti PR, Raffaelli L. An overview of zirconia ceramics: Basic proper-

[121] Pareja RR, Ibáñez RL, Martín F, Ramos-Barrado JR, Leinen D. Corrosion behaviour of zirconia barrier coatings on galvanized steel. Surface and Coatings Technology.

[122] Puntervold T, Strand S, Austad T. Water flooding of carbonate reservoirs: Effects of a model base and natural crude oil bases on chalk wettability. Energy and Fuels.

[123] Love JC, Estroff LA, Kriebel JK, Nuzzo RG, Whitesides GM. Self assembled monolayers of thiolates on metals as a form of nanotechnology. Chemical Reviews. 2005;

[124] Iglauer S, Salamah A, Sarmadivaleh M, Liu K, Phan C. Contamination of silica sur-

[125] Sarmadivaleh M, Al-Yaseri AZ, Iglauer S. Influence of temperature and Presssure on

[126] Mahdi Jafari S, He Y, Bhandari B. Nano-emulsion production by sonication and microfluidization-a comparison. International Journal of Food Properties. 2006;**9**(3):475-485

[127] Lander LM, Siewierski LM, Brittain WJ, Vogler EA. A systematic comparison of contact



ties and clinical applications. Journal of Dentistry. 2007;**35**(11):819-826

[115] Zhang HH, Ma CY, Zhang QY. Scaling behavior and structure transition of ZrO<sup>2</sup>

deposited by RF magnetron sputtering. Vacuum. 2009;**83**(11):1311-1316

[114] Lopez CM, Suvorova NA, Irene EA, Suvorova AA, Saunders M. ZrO<sup>2</sup>

Thin Solid Films. 2016;**619**:231-238

[117] Tanabe K. Surface and catalytic properties of ZrO<sup>2</sup>

with Si and SiO<sup>2</sup>

356 Novel Nanomaterials - Synthesis and Applications

1985;**13**(3-4):347-364

2006;**200**(22):6606-6610

2007;**21**(3):1606-1616

**105**(4):1103-1170

quartz-water-CO<sup>2</sup>

Science. 2015;**441**:59-64

faces: Impact on water-CO<sup>2</sup>

Journal of Greenhouse Gas Control. 2014;**22**:325-328

angle methods. Langmuir. 1993;**9**(8):2237-2239

contact angle and CO2

**36**(A4):481

interlayer on the electrical and transport properties of au/n-type InP Schottky diode.

)

films

film interfaces

. Materials Chemistry and Physics.

