**2. Traditional transmission FT-IR (T-FTIR) spectroscopy in environmental studies**

Transmission spectroscopy is the oldest and most commonly used method for identifying either organic or inorganic chemicals providing specific information on molecular structure, chemical bonding and molecular environment. It can be applied to study solids, liquids or gaseous samples being a powerful tool for qualitative and quantitative studies.

FTIR instrument's principle of function is the following: IR radiation from the source that hits the beam splitter is partly directed towards the two mirrors arranged as shown in Figure 2. One of the two mirrors is stationary, and the other is moved at a constant velocity during data acquisition. As it can be seen in Figure 2 at first the IR beams are reflected by mirrors, after that are recombined at the beam splitter, and then passed through the sample and reach the detector. This records all wavelengths in the IR range. After the two beams reflected by the mirrors recombine, they will travel different distances, and the recombination will lead to constructive and destructive interference. The result will be an interferogram. After the recombined beam has passed through the sample the detector will record the Fourier transform of the IR spectrum of the sample. The data obtained are then processed by a computer that performs an additional Fourier transform to back-transform the interferogram into an IR spectrum (Smith *et al.,* 2011; Blum and John, 2012).

50 Advanced Aspects of Spectroscopy

Infrared radiation is divided into:


FT-IR spectroscopy.

pollutants simultaneously.

**environmental studies** 


Because all compounds show characteristic absorption/emission in the IR spectral region and based on this property they can be analyzed both quantitatively and qualitatively using

Today FT-IR instruments are digitalized and are faster and more sensitive than the older ones. FT-IR spectrometers can detect over a hundred volatile organic compounds (VOC) emitted from industrial and biogenic sources. Gas concentrations in stratosphere and

In case of environmental studies FTIR Spectroscopy is used to analyze relevant amount of compositional and structural information concerning environmental samples (Grube *et al.,* 2008). The analysis can be performed also to determine the nature of pollutants, but also to determine the bonding mechanism in case of pollutants removal by sorption processes. Techniques for measuring gas pollutants such as continuous air pollutants analyzer (SO2, NO2, O3, NH3), on-line gas chromatography (GC) used simple real-time instruments to quantify gas pollutants. They need to use several sensors in order to analyze multiple gas

FT-IR spectroscopy coupled with other spectroscopic techniques such as AAS (atomic absorption spectroscopy) have been used to assess the impact of industrial and natural

In addition to the traditional transmission FTIR (T-FTIR) methods (e.g. KBr-pellet or mull techniques), modern reflectance techniques are widely used today in environmental, agricultural, pharmaceuticals, and food studies. These modern techniques are attenuated total reflection FTIR (ATR-FTIR), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The choice of the method to be used depends on many factors such as: the information needed (bulk versus surface analysis), the physical form of the sample,

In the following there will be presented some of the most important research studies related

Transmission spectroscopy is the oldest and most commonly used method for identifying either organic or inorganic chemicals providing specific information on molecular structure, chemical bonding and molecular environment. It can be applied to study solids, liquids or

troposphere were determined using FT-IR spectrometers (Puckrin *et al*., 1996).

activities on air quality (Kumar *et al*., 2005; Childers *et al*., 2001).

the time required for sample preparation (Majedová *et al*., 2003).

to the involvement of FTIR spectroscopy in environmental studies.

**2. Traditional transmission FT-IR (T-FTIR) spectroscopy in** 

gaseous samples being a powerful tool for qualitative and quantitative studies.

**Figure 2.** A schematic representation of an interferometer used in FTIR spectrometers (adapted from Blum and John, 2012 with permission (originally published in Drug Test. Analysis, DOI: 10.1002/dta.374 ))

The potential value of FTIR spectroscopy to a wide range of environmental applications has been demonstrated by numerous research studies. Some of them are presented below.

A review by McKelvy and coworkers containing 132 references at the chapter related to environmental applications of infrared spectroscopy (McKelvy *et al*., 1998) covers the published literature about relevant applications of infrared spectroscopy for chemical analysis. The literature research was made for the period November 1995 to October 1997. The review contains aspects about infrared accessories and sampling techniques, infrared techniques, applications of infrared spectroscopy in environmental analysis, synthesis chemistry, food and agriculture, biochemistry and also the books and reviews appeared in that period for this subject (McKelvy *et al*., 1998). An other review concerning the nearinfrared and infrared spectroscopy was made by Workman Jr. This review covers the period 1993-1999 and presents the application of the near infrared spectral region to all types of analyses (Workman Jr, 1999).

The basic principle and methods of FTIR spectroscopy of the atmosphere are presented by Bacsik and coworkers in 2004 (Bacsik *et al*., 2004). The same group of researchers published a review article related to the most significant and frequent applications of FTIR spectroscopy to the study of the atmosphere (Basick *et al*., 2005). The authors summarized the basic literature in the field of special environmental applications of FTIR spectroscopy, such as power plants, petrochemical and natural gas plants, waste disposals, agricultural, and industrial sites, and the detection of gases produced in flames, in biomass burning, and in flares (Basick *et al*., 2005).

Applications of FTIR spectroscopy to agricultural soils analysis were presented and discussed by Raphael in the book entitled "Fourier Transforms - New Analytical Approaches and FTIR Strategies" (Raphael, 2011). Chapter 19 of the same book presents the application of FTIR spectroscopy in waste management, and chapter 21 presents the study of trace atmospheric gases using Ground-Based Solar Fourier Transform Infrared Spectroscopy (Smidt *et al*., 2011; Paton-Wals, 2011).

In case of air pollution the Fourier transform infrared (FTIR) instrument is used succesfully for measuring gas pollutants due to its many advantages such as: multiple gas pollutants will be monitored in real time, the IR spectra of sample can be analyzed and preserved for a long time, can be use to detect and measure directly both criteria and toxic pollutants in ambient air, measures also organic and inorganic compounds, can be also used to characterize and analyze microorganisms and monitor biotechnological processes, is generally installed at one location, but can be also portable and operated using battery for short-term survey, presents sensitivity from very low parts per million to high percent levels, can be applied to the analysis of solids, liquids and gases, no reagent is needed, and data acquisition is faster than with other physico-chemical techniques (Santos *et al*., 2010).

The basic principle of FT-IR spectroscopy used in air pollutants detection and measuring is that every gas has its own "fingerprint" or absorption spectrum. The entire infrared spectrum will be monitored and FTIR sensor will read the different fingerprints of the gases present in the air sample. In case of determination of gas concentrations from stratosphere, the FT-IR spetrometers have to be designed with a fine resolution (0.01 cm-1) due to the lower atmospheric pressure, and with a lower resolution between 0.05 cm-1 and 2 cm-1 for tropospheric gases determination. This is due to pressure broadening effects that result in broadened absorption lines. In troposphere water vapor concentrations are higher than those from stratosphere and they have a negative effect on the FT-IR spectrum measurements. The strong interference of water vapor in troposphere is overcome by detecting chemical substances in narrow bands of the IR spectrum where water absorption is very weak.

The total precipitable water vapour (PWV) from air which is responsible for the greenhouse effect being the most important trace gas can be measure using FT-IR spectroscopy. When it was compared with other instruments such as a Multifilter Rotating Shadow-band Radiometer (MFRSR), a Cimel sunphotometer, a Global Positioning System (GPS) receiver, and daily radiosondes (Vaisala RS92) it was estimated that FTIR spectrometer provides very precise trophospheric water vapour data, but when area-wide coverage and real-time data availability is very important, the GPS and the RS92 data are more appropriate. FTIR spectroscopy can be use also as a reference when assessing the accuracy of the other techniques, but those who use this technique have to be aware of the FTIR's significant clear sky bias (Schneider, 2010).

52 Advanced Aspects of Spectroscopy

flares (Basick *et al*., 2005).

is very weak.

Spectroscopy (Smidt *et al*., 2011; Paton-Wals, 2011).

The basic principle and methods of FTIR spectroscopy of the atmosphere are presented by Bacsik and coworkers in 2004 (Bacsik *et al*., 2004). The same group of researchers published a review article related to the most significant and frequent applications of FTIR spectroscopy to the study of the atmosphere (Basick *et al*., 2005). The authors summarized the basic literature in the field of special environmental applications of FTIR spectroscopy, such as power plants, petrochemical and natural gas plants, waste disposals, agricultural, and industrial sites, and the detection of gases produced in flames, in biomass burning, and in

Applications of FTIR spectroscopy to agricultural soils analysis were presented and discussed by Raphael in the book entitled "Fourier Transforms - New Analytical Approaches and FTIR Strategies" (Raphael, 2011). Chapter 19 of the same book presents the application of FTIR spectroscopy in waste management, and chapter 21 presents the study of trace atmospheric gases using Ground-Based Solar Fourier Transform Infrared

In case of air pollution the Fourier transform infrared (FTIR) instrument is used succesfully for measuring gas pollutants due to its many advantages such as: multiple gas pollutants will be monitored in real time, the IR spectra of sample can be analyzed and preserved for a long time, can be use to detect and measure directly both criteria and toxic pollutants in ambient air, measures also organic and inorganic compounds, can be also used to characterize and analyze microorganisms and monitor biotechnological processes, is generally installed at one location, but can be also portable and operated using battery for short-term survey, presents sensitivity from very low parts per million to high percent levels, can be applied to the analysis of solids, liquids and gases, no reagent is needed, and data acquisition is faster than with other physico-chemical techniques (Santos *et al*., 2010).

The basic principle of FT-IR spectroscopy used in air pollutants detection and measuring is that every gas has its own "fingerprint" or absorption spectrum. The entire infrared spectrum will be monitored and FTIR sensor will read the different fingerprints of the gases present in the air sample. In case of determination of gas concentrations from stratosphere, the FT-IR spetrometers have to be designed with a fine resolution (0.01 cm-1) due to the lower atmospheric pressure, and with a lower resolution between 0.05 cm-1 and 2 cm-1 for tropospheric gases determination. This is due to pressure broadening effects that result in broadened absorption lines. In troposphere water vapor concentrations are higher than those from stratosphere and they have a negative effect on the FT-IR spectrum measurements. The strong interference of water vapor in troposphere is overcome by detecting chemical substances in narrow bands of the IR spectrum where water absorption

The total precipitable water vapour (PWV) from air which is responsible for the greenhouse effect being the most important trace gas can be measure using FT-IR spectroscopy. When it was compared with other instruments such as a Multifilter Rotating Shadow-band Radiometer (MFRSR), a Cimel sunphotometer, a Global Positioning System (GPS) receiver, and daily radiosondes (Vaisala RS92) it was estimated that FTIR spectrometer provides very Animal farms are major sources of air pollution with ammonia and greenhouse gases. Air concentration of these pollutants may be higher or lower depending on the systems used. In addition, these systems have to correspond both in terms of animal welfare, and in terms of environmental protection. If it is considered animal welfare, the straw based systems are considered animal friendly systems, and when it is considered the environmental protection, the slurry based systems are preferred, due to lower ammonia (NH3) and greenhouse gas (GHG) emissions. For slurry based systems air pollutants emissions were intensively researched, and the specific emission factors for several slurry-based housing systems for pigs are mentioned in the "Guidance document on control techniques for preventing and abating emissions of ammonia" developed by the UN/ECE "Expert Group on Ammonia Abatement" of the "Executive Body for the Convention on Long-Range Transboundary Air Pollution" (EB.AIR/1999/2). The straw based systems have not been extensively studied in terms of emissions of air pollutants. There are few research studies regarding these systems. Thus, high resolution FTIR spectrometry was used in order to determine the emissions of ammonia (NH3), nitrous oxide (N2O), methane (CH4), and volatile organic compounds (VOC) at a commercial pig farm in Upper Austria using a straw flow system by Amon and coworkers (Amon *et al*., 2007). The straw flow system is an animal friendly housing system for fattening pigs, being often equated with deep litter where there is no separation between the lying and the excretion areas. In deep litter systems most of the pigs welfare requirements are fulfilled. The main disadvatages of these systems are that there is a high straw consumption, the pigs are dirtier and the deep litter are characterized by high levels of NH3 and greenhouse gases (GHG). Thus the level of NH3 and greenhouse gases (GHG) has to be monitored in order to control and to avoid air pollution and to take appropriate measures for environment protection. For the pig farm monitored by Amon and coworkers it can be concluded that the straw flow system may combine recommendations of animal welfare and environmental protection (Amon *et al*., 2007).

Environmental problems are also due to the incorect application of manure. The main air pollutants associated with manure application are ammonia, and nitrous oxides. In order to develop new environmentaly friendly methods for manure applications all aspects have to be investigated. For this purpose Galle and coworkers made some area-integrated measurements of ammonia emissions after spreading of pig slurry on a wheat field, based on gradient measurements using FTIR spectroscopy. They concluded that the gradient method is valuable for measurement of ammonia emissions from wide area, although the detection limits of the system limits its use to the relatively high emissions (Galle *et al*., 2000).

In another study Jäger and coworkers reported that FTIR spectroscopy is capable of measuring low concentrations of CO2, CH4, N2O and CO as well as isotope ratios (especially that of 13CO2) in gas samples. The concentration levels of these gases are close to them in environmental air (Jäger *et al*. 2011). In the same paper the authors discussed also about the accuracy and stability of the FTIR instrument.

Volcanoes are considered important natural sources of air pollution. The most abundant gas typically released into the atmosphere by volcanoes is water vapor (H2O), followed by carbon dioxide (CO2) and sulfur dioxide (SO2). Other gases such as hydrogen sulfide (H2S), carbon monoxide (CO), hydrochloric acid (HCl), hydrofluoric acid (HF), hydrogen (H2), helium (He), silicon tetrafluoride (SiF4), carbon oxysulfide (COS) are released by volcanoes in small amounts. From the most dangerous to human, animals and agriculture are carbon dioxide, sulfur dioxide and hydrofluoric acid. Therefore it is important to monitor volcanic activities.

The first report about determination of HCl and SO2 in volcanic gas dates from 1993 when Mori and coworkers used an FT-IR spectrometer during a stage of dome lava extrusion of the Unzen volcano (Mori *et al*., 1993). Other gases including H2O, CO2, CO, COS, SO2, HF were measured using a remote FT-IR spectral radiometer (Mori and Notsu, 1997; Francis *et al*., 1996; Love *et al*., 1998; Burton *et al.,* 2000; Mori and Notsu, 2008).

A telescope-attached FT-IR spectral radiometer was used to study the volcanic gases in seven active volcanoes from Japan. For one of the volcanoes monitored the authors have been used infrared radiation from hot lava domes, for three of them they used infrared radiation of the hot ground surface, and for the other three they used scattered solar light, as infrared sources. The observations over 15 years suggest that HCl/SO2 and HF/HCl ratios are the most promising parameters reflecting volcanic activity among various parameters observable in remote FI-IR measurements (Notsu and Mori, 2010).

Oppenheimer and coworkers used thermal imaging and spectroscopic (FTIR) techniques to characterize phase-locked cycles of lava lake convection and gas plume composition of the Erebus volcano, Antarctica - a volcano continuously active for decades being now in steadystate. The authors identified a striking, cyclic correspondence between the surface motion of lava lake, and its heat and gas output. They concluded that this can be a reflection of unsteady, bi-directional magma flow in the conduit feeding the lake. It was also determined the ratio between gases emitted by volcanic lake, and the very tight correlation between CO2 and CO was attributed to the redox equilibrium established in the lava lake. These results have a great contribution to the understanding of the laboratory models for magma convection degassing and volcanic gas geochemistry (Oppenheimer et al., 2009).

FTIR technique offers the potential for the non-destructive, simultaneous, real-time measurement of multiple gas phase compounds in complex mixtures such as cigarette smoke (Bacsik *et al*., 2007a). Thus, in a study Bacsik and coworkers reported using of FTIR spectroscopy to study the mainstream cigarette smoke from cigarettes of different stated strengths (regular and various light cigarettes with different reported nicotine, tar and CO contents) (Bacsik, 2007b). The cigarette smoke is a very complex mixture that mainly consists of hydrocarbons and both carbon and nitrogen oxides. The results obtained by the authors reveal the fact that the strength of the cigarettes does not have a significant bearing on the quantity of the observed components obtained (Bacsik, 2007b).

54 Advanced Aspects of Spectroscopy

activities.

accuracy and stability of the FTIR instrument.

In another study Jäger and coworkers reported that FTIR spectroscopy is capable of measuring low concentrations of CO2, CH4, N2O and CO as well as isotope ratios (especially that of 13CO2) in gas samples. The concentration levels of these gases are close to them in environmental air (Jäger *et al*. 2011). In the same paper the authors discussed also about the

Volcanoes are considered important natural sources of air pollution. The most abundant gas typically released into the atmosphere by volcanoes is water vapor (H2O), followed by carbon dioxide (CO2) and sulfur dioxide (SO2). Other gases such as hydrogen sulfide (H2S), carbon monoxide (CO), hydrochloric acid (HCl), hydrofluoric acid (HF), hydrogen (H2), helium (He), silicon tetrafluoride (SiF4), carbon oxysulfide (COS) are released by volcanoes in small amounts. From the most dangerous to human, animals and agriculture are carbon dioxide, sulfur dioxide and hydrofluoric acid. Therefore it is important to monitor volcanic

The first report about determination of HCl and SO2 in volcanic gas dates from 1993 when Mori and coworkers used an FT-IR spectrometer during a stage of dome lava extrusion of the Unzen volcano (Mori *et al*., 1993). Other gases including H2O, CO2, CO, COS, SO2, HF were measured using a remote FT-IR spectral radiometer (Mori and Notsu, 1997; Francis *et* 

A telescope-attached FT-IR spectral radiometer was used to study the volcanic gases in seven active volcanoes from Japan. For one of the volcanoes monitored the authors have been used infrared radiation from hot lava domes, for three of them they used infrared radiation of the hot ground surface, and for the other three they used scattered solar light, as infrared sources. The observations over 15 years suggest that HCl/SO2 and HF/HCl ratios are the most promising parameters reflecting volcanic activity among various parameters

Oppenheimer and coworkers used thermal imaging and spectroscopic (FTIR) techniques to characterize phase-locked cycles of lava lake convection and gas plume composition of the Erebus volcano, Antarctica - a volcano continuously active for decades being now in steadystate. The authors identified a striking, cyclic correspondence between the surface motion of lava lake, and its heat and gas output. They concluded that this can be a reflection of unsteady, bi-directional magma flow in the conduit feeding the lake. It was also determined the ratio between gases emitted by volcanic lake, and the very tight correlation between CO2 and CO was attributed to the redox equilibrium established in the lava lake. These results have a great contribution to the understanding of the laboratory models for magma

FTIR technique offers the potential for the non-destructive, simultaneous, real-time measurement of multiple gas phase compounds in complex mixtures such as cigarette smoke (Bacsik *et al*., 2007a). Thus, in a study Bacsik and coworkers reported using of FTIR spectroscopy to study the mainstream cigarette smoke from cigarettes of different stated strengths (regular and various light cigarettes with different reported nicotine, tar and CO contents) (Bacsik, 2007b). The cigarette smoke is a very complex mixture that mainly

convection degassing and volcanic gas geochemistry (Oppenheimer et al., 2009).

*al*., 1996; Love *et al*., 1998; Burton *et al.,* 2000; Mori and Notsu, 2008).

observable in remote FI-IR measurements (Notsu and Mori, 2010).

An other anthropic source of air pollution is aircraft flight. The main pollutants released by aircrafts are unburnt hydrocarbons, carbon monoxide, and nitrogen oxides. The level of these pollutants is higher near the airport. For modern aircrafts the level of pollutants emissions is lower due to the using of more efficient turbine engine. Nevertheless the civil aviation authorities require the monitoring emissions from aircraft in airports and in the vicinity of airports. For this a non-intrusive Fourier Transform Infrared (FTIR) spectroscopy has been used to detect hydrocarbons in emissions from gas turbine engines (Arrigone and Hilton, 2005). The advantages of this mentioned techniques reported by Arrigone and Hilton are: it is non-intrusive—no sampling system is required and there is no physical interference with the exhaust plume while measurements are made; is useful for simultaneous monitoring of several species; the equipment is portable and can be simply set up and used outside the laboratory in engine test facilities, airfields (Arrigone and Hilton, 2005).

All these advantages encourage the use of FTIR spectroscopy as a valuable tool in monitoring emissions from aircraft in airports.

Quantitative information about air components and air pollutants is needed to study the impact of pollutants (gaseous, liquids or solids) on human health and atmospheric chemistry. To obtain these information an infrared spectral database was created. This database was completed with spectral information of gases emitted by biomass burning by Johnson and coworkers. The following classes of compounds: singly- and doubly-nitrogensubstituted aromatic, terpenes, hemi-terpenes, retenes and other pyrolysis biomarker compounds, carboxylic acids and dicarboxylic acids were identified in gases from biomass burning (Johnson *et al.,* 2010).

Throughout, latest years, the significance of bioaerosols has been discussed in environmental and occupational hygiene. Identification of microorganisms using cultivation and microscopic examination is time consuming and alone does not provide sufficient information with respect to the evaluation of health hazards in connection with bioaerosol exposure. FT-IR spectroscopy has widely been used for the characterization and identification of bacteria and yeasts, due to the fact that they are hydrophilic microorganisms and can easily be suspended in water for sample preparation (Essendoubi *et al*., 2005; Duygu *et al*., 2009). The identification of airborne fungi using FT-IR spectroscopy was described by Fischer and coworkers. They found that the method was suited to reproducibly differentiate *Aspergillus* and *Penicillium* species. The results obtained can serve as a basis for the development of a database for species identification and strain characterization of microfungi (Fischer *et al*., 2006).

Studies on heavy metals and organic compounds removal from wastewaters using different natural and synthetic materials are many. The important role of FTIR spectroscopy in such studies is either related to the characterization of sorbents, chemical modified sorbents, or to

establish the mechanism involved in sorption processes (Cheng *et al*., 2012; Chen and Wang, 2012; Xu *et al*., 2012; Ma *et al*., 2012a; Wang *et al*., 2011; Jordan *et al*., 2011; Bardakçi and Bahçeli, 2010; Pokrovsky *et al*., 2008; Parolo *et al*., 2008).

Biosorption is considered as an alternative process for the removal of heavy metals, metalloid species, compounds and particles from aqueous solution by biological materials (Mungasavalli *et al*., 2007). Biomaterials are adsorbent materials with high heavy metals adsorption capacity. They have many advantages such as reusability, low operating cost, improved selectivity for specific metals of interests, removal of heavy metals found in low concentrations in wastewaters, short operation time, and no production of secondary compounds which can be toxic (Mungasavalli *et al*., 2007). FTIR spectroscopy can be used for characterization of biomaterials used in depolluting processes, but also to characterize materials obtained after chemical modification of them. Thus we used FTIR spectroscopy to characterize the material obtained after chemical modification of chitosan with glutardialdehyde in order to obtain a product with good sorption properties (Deleanu *et al*., 2008), but also to characterize the materials obtained after alkaline treatment of bentonite to increase its capacity to retain ammonium ions from synthetic solutions (Simonescu *et al.,* 2005).

FT-IR spectroscopy has been used to identify the nature of possible sorbent (biosorbent) – pollutants (heavy metals, inorganic compounds, organic compounds) interactions.

For copper removal by fungal biomass to determine the characteristic functional groups that are responsible for biosorption of copper ions were made biomass's FTIR spectra before and after the bisorption process took place. The bonding mechanism between copper and biomass (fungal strain, cyanobacteria or other microorganism) (Yee *et al*., 2004; Burnett *et al*., 2006) can be determined by interpreting the infrared absorption spectrum.

We used in our studies fungal strains in order to remove heavy metals from synthetic waters which contain also copper in the form of copper sulfide nanoparticles, but also copper in dissolved state. In case of copper biosorption by *Aspergillus oryzae* ATCC 20423 the FTIR spectra registered are presented in Figure 3. The FTIR spectrum for *Aspergillus oryzae* ATCC 20423 before copper biosorption is presented in Figure 3a, the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 25 mg copper/L is presented in Figure 3b, the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 50 mg copper/L is presented in Figure 3c, the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 75 mg copper/L is presented in Figure 3d, and the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 100 mg copper/L is presented in Figure 3e.

From the Figure 3 it can be seen that all five FTIR spectra present distinct peaks in the following ranges: 3393 – 3418 cm-1, 2926 – 2968 cm-1, 1629 – 1638 cm-1, 1404 – 1405 cm-1, 1073 - 1077 cm-1, and 529 – 533 cm-1. The broad and strong band situated in the range 3393 – 3418 cm-1 can be attributed to overlapping of –OH and –NH stretching. The band from the range 2926 – 2968 cm-1 is attributed to the C-H stretching vibrations. The strong peak at 1629 – 1638 cm-1

56 Advanced Aspects of Spectroscopy

2005).

Bahçeli, 2010; Pokrovsky *et al*., 2008; Parolo *et al*., 2008).

establish the mechanism involved in sorption processes (Cheng *et al*., 2012; Chen and Wang, 2012; Xu *et al*., 2012; Ma *et al*., 2012a; Wang *et al*., 2011; Jordan *et al*., 2011; Bardakçi and

Biosorption is considered as an alternative process for the removal of heavy metals, metalloid species, compounds and particles from aqueous solution by biological materials (Mungasavalli *et al*., 2007). Biomaterials are adsorbent materials with high heavy metals adsorption capacity. They have many advantages such as reusability, low operating cost, improved selectivity for specific metals of interests, removal of heavy metals found in low concentrations in wastewaters, short operation time, and no production of secondary compounds which can be toxic (Mungasavalli *et al*., 2007). FTIR spectroscopy can be used for characterization of biomaterials used in depolluting processes, but also to characterize materials obtained after chemical modification of them. Thus we used FTIR spectroscopy to characterize the material obtained after chemical modification of chitosan with glutardialdehyde in order to obtain a product with good sorption properties (Deleanu *et al*., 2008), but also to characterize the materials obtained after alkaline treatment of bentonite to increase its capacity to retain ammonium ions from synthetic solutions (Simonescu *et al.,*

FT-IR spectroscopy has been used to identify the nature of possible sorbent (biosorbent) –

For copper removal by fungal biomass to determine the characteristic functional groups that are responsible for biosorption of copper ions were made biomass's FTIR spectra before and after the bisorption process took place. The bonding mechanism between copper and biomass (fungal strain, cyanobacteria or other microorganism) (Yee *et al*., 2004; Burnett *et al*.,

We used in our studies fungal strains in order to remove heavy metals from synthetic waters which contain also copper in the form of copper sulfide nanoparticles, but also copper in dissolved state. In case of copper biosorption by *Aspergillus oryzae* ATCC 20423 the FTIR spectra registered are presented in Figure 3. The FTIR spectrum for *Aspergillus oryzae* ATCC 20423 before copper biosorption is presented in Figure 3a, the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 25 mg copper/L is presented in Figure 3b, the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 50 mg copper/L is presented in Figure 3c, the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 75 mg copper/L is presented in Figure 3d, and the FTIR spectrum of *Aspergillus oryzae* ATCC 20423 after growth in the presence of copper solution with 100 mg

From the Figure 3 it can be seen that all five FTIR spectra present distinct peaks in the following ranges: 3393 – 3418 cm-1, 2926 – 2968 cm-1, 1629 – 1638 cm-1, 1404 – 1405 cm-1, 1073 - 1077 cm-1, and 529 – 533 cm-1. The broad and strong band situated in the range 3393 – 3418 cm-1 can be attributed to overlapping of –OH and –NH stretching. The band from the range 2926 – 2968 cm-1 is attributed to the C-H stretching vibrations. The strong peak at 1629 – 1638 cm-1

pollutants (heavy metals, inorganic compounds, organic compounds) interactions.

2006) can be determined by interpreting the infrared absorption spectrum.

copper/L is presented in Figure 3e.

**Figure 3.** FT-IR spectra of *Aspergillus oryzae* ATCC 20423 unloaded (a) and loaded with Cu(II) ions (b-e)

can be due to a C=O stretching in carboxyl or amide groups. The peak at 1404 – 1405 cm-1 is attributed to N-H bending in amine group. The band observed at 1073 - 1077 cm-1 was assigned to the CO stretching of alcohols and carboxylic acids. Thus *Aspergillus oryzae*  ATCC 20423 biomass contains hydroxyl, carboxyl and amine groups on surface.

From the Figures 3b-e it can be seen that the stretching vibration of OH group was shifted from 3393 cm-1 to 3418 cm-1 (3b), to 3398 cm-1 (3d), 3406 cm-1 (3e). These results revealed that chemical interactions between the copper ions and the hydroxyl groups occurred on the

biomass surface. The carboxyl peak observed for unloaded biomass at 1638 cm-1 is shifted to 1634 cm-1 or 1629 cm-1. This decrease in the wave number of the peak characteristic for C=O group from carboxylic acid revealed that interacts with carbonyl functional group are present between biomass and copper ions. These results indicated that the free carboxyl groups changed into carboxylate, which occurred during the reaction of the metal ions and carboxyl groups of the biosorbent.

No frequency changes were observed in the C-H and -NH2 groups of biomass after copper biosorption. In addition, all FTIR spectrum of *Aspergillus oryzae* ATCC 20423 loaded with copper ions contain bands at 533, 529, 525 cm-1 which can be attributed to Cu-O stretching modes (Simonescu and Ferdes*, in press*).

The similar FT-IR results were reported for the biosorption Pb(II), Cd(II) and Cu(II) onto *Botrytis cinerea* fungal biomass (Akar *et al*., 2005) and Pb(II) and Cd(II) from aqueous solution by macrofungus (*Lactarius scrobiculatus*) biomass (Anayurt *et al*., 2009).

In our work we used also FT-IR spectroscopy in order to determine the characteristic functional groups which are responsible for biosorption of copper ions by *Polyporus squamosus*, *Aspergillus oryzae* NRRL 1989 (USA), *Aspergillus oryzae* 22343 (Simonescu *et al*., 2012).

In case of biological degradation of pollutants a significant role can be attributed to biodegradation pathway due to the fact that different biodegradation pathways lead to different biodegradation products. Thus it is important to determine biodegradation pathways. For this purpose FTIR spectroscopy is a relevant tool for rapid determination of the resulting biotransformation product or mixtures. With this respect, Huang and coworkers investigated the ability of FT-IR to distinguish two different m-cresol metabolic pathways in *Pseudomonas putida* NCIMB 9869 after growth on 3,5-xylenol or m-cresol. From this study, it can be concluded that FT-IR spectral fingerprints were shown to differentiate metabolic pathways of m-cresol within the same bacterial strain and thus FTIR spectroscopy might provide a rapid, non-destructive, cost-effective approach for assessing of products resulted in biological degradation of pollutants (Huang *et al*., 2006).

The main directions of use of FTIR spectroscopy in waste management are about getting information regarding the stage of organic matter for process and product control, and for monitoring of landfill remediation. For this purpose, Smidt and Meissl used FTIR spectroscopy to asses the stage of organic matter decomposition in waste materials (Smidt and Meissl, 2007). The results obtained confirm that FTIR spectroscopy represents an appropriate tool for process and quality control, for the assessment of abandoned landfills and for monitoring and checking of the successful landfill remediation (Smidt and Meissl, 2007).

The structural changing in biodegradation processes can be determined by FTIR analysis. Thus Tomšič and coworkers studied structural changes of cellulose fabric modified by imidazolidinone biodegradation after different period using electron microscopic and spectroscopic analyses (Tomšič *et al*., 2007). Also FT-IR spectroscopy is a quick and useful method to monitor the composting process (Grube *et al*., 2006). The aim of them study was to elucidate the typical IR absorption bands and correlation of band growth rates with the compost maturity or degradation degree. The results of this study revealed that IR spectroscopy is a simple, quick and informative method that can be used instead of several time consuming chemical methods for monitoring of routine composting processes.

58 Advanced Aspects of Spectroscopy

2012).

carboxyl groups of the biosorbent.

modes (Simonescu and Ferdes*, in press*).

biomass surface. The carboxyl peak observed for unloaded biomass at 1638 cm-1 is shifted to 1634 cm-1 or 1629 cm-1. This decrease in the wave number of the peak characteristic for C=O group from carboxylic acid revealed that interacts with carbonyl functional group are present between biomass and copper ions. These results indicated that the free carboxyl groups changed into carboxylate, which occurred during the reaction of the metal ions and

No frequency changes were observed in the C-H and -NH2 groups of biomass after copper biosorption. In addition, all FTIR spectrum of *Aspergillus oryzae* ATCC 20423 loaded with copper ions contain bands at 533, 529, 525 cm-1 which can be attributed to Cu-O stretching

The similar FT-IR results were reported for the biosorption Pb(II), Cd(II) and Cu(II) onto *Botrytis cinerea* fungal biomass (Akar *et al*., 2005) and Pb(II) and Cd(II) from aqueous

In our work we used also FT-IR spectroscopy in order to determine the characteristic functional groups which are responsible for biosorption of copper ions by *Polyporus squamosus*, *Aspergillus oryzae* NRRL 1989 (USA), *Aspergillus oryzae* 22343 (Simonescu *et al*.,

In case of biological degradation of pollutants a significant role can be attributed to biodegradation pathway due to the fact that different biodegradation pathways lead to different biodegradation products. Thus it is important to determine biodegradation pathways. For this purpose FTIR spectroscopy is a relevant tool for rapid determination of the resulting biotransformation product or mixtures. With this respect, Huang and coworkers investigated the ability of FT-IR to distinguish two different m-cresol metabolic pathways in *Pseudomonas putida* NCIMB 9869 after growth on 3,5-xylenol or m-cresol. From this study, it can be concluded that FT-IR spectral fingerprints were shown to differentiate metabolic pathways of m-cresol within the same bacterial strain and thus FTIR spectroscopy might provide a rapid, non-destructive, cost-effective approach for assessing of products

The main directions of use of FTIR spectroscopy in waste management are about getting information regarding the stage of organic matter for process and product control, and for monitoring of landfill remediation. For this purpose, Smidt and Meissl used FTIR spectroscopy to asses the stage of organic matter decomposition in waste materials (Smidt and Meissl, 2007). The results obtained confirm that FTIR spectroscopy represents an appropriate tool for process and quality control, for the assessment of abandoned landfills and for monitoring and

The structural changing in biodegradation processes can be determined by FTIR analysis. Thus Tomšič and coworkers studied structural changes of cellulose fabric modified by imidazolidinone biodegradation after different period using electron microscopic and spectroscopic analyses (Tomšič *et al*., 2007). Also FT-IR spectroscopy is a quick and useful method to monitor the composting process (Grube *et al*., 2006). The aim of them study was

solution by macrofungus (*Lactarius scrobiculatus*) biomass (Anayurt *et al*., 2009).

resulted in biological degradation of pollutants (Huang *et al*., 2006).

checking of the successful landfill remediation (Smidt and Meissl, 2007).

Soil is a complex medium with important ecological functions. Its functions depend on its characteristics. FTIR spectroscopy can be used to describe soil characteristics in the form of complex multivariate data sets. Thus FTIR spectroscopy has been used by Elliott and coworkers to investigate soils at different stages of recovery from degradation following opencast mining and from undisturbed land (Elliott *et al*., 2007). When a FT-IR spetrometer was used to determine gases from soils and rock formations no other gases than CO2 have been detected except CO in the open-path compartment dedicated to atmosphere analysis (Pironon *et al*., 2009).

The use of living organisms to manage or remediate polluted soils named bioremediation represents an emerging technology. This technology is defined as the elimination, attenuation or transformation of polluting or contaminating substances by the use of biological processes. The results *in situ* bioremediation depend by microbial strains from contaminated site. The biodegradation process can be monitored by FTIR spectroscopy. For this purpose Bhat and coworkers performed a study about remediation of hydrocarbon contaminated soil through microbial degradation. The bacterial strains involved in bioremediation process were collected to be isolated from contaminated soil. FTIR spectra of untreated and treated soil samples revealed that the isolated bacterial strains have a substantial potential to remediate the hydrocarbon contaminated soils (Bhat *et al*., 2011).

Biomineralization has an important role for pollutants removal from environment. It has been known the mecanism involved in such processes to establish the nature of intemediates and final compound formed. FTIR spectroscopy is well-suited for such investigations, because it provides simultaneously molecular-scale information on both organic and inorganic constituents of a sample. Consequently FTIR spectroscopy was used in several complementary sample introduction modes as transmission (T-FTIR), attenuated total reflectance (ATR-FTIR), diffuse reflectance (DRIFTS) to analyze the processes of cell adhesion, biofilm growth, and biological Mn-oxidation by *Pseudomonas putida* strain GB-1 by Parikh and Chorover (Parikh and Chorover, 2005).

Fourier Transform Infrared (FT-IR) and Attenuated Total Reflectance (ATR) spectroscopy in the mid infrared (MIR) wavelength range (2500 – 16,000 nm) have been also developed for contaminant detection in water (Gowen *et al*., 2011a). The authors tested the near infrared spectroscopy (NIRS) for the detection and quantification of pesticides including Alachlor and Atrazine in aqueous solution. Calibration models were built to predict pesticide concentration using PLS regression (PLSR). The proposed method shows potential for direct measurement of low concentrations of pesticides in aqueous solution. The research was performed in the laboratory conditions, and it is well known that the NIR spectrum of aqueous samples is susceptible to changes in the environment (e.g. temperature, humidity) and sample (e.g. pH, turbidity). Thus further experiments are necessary to test the effect of such perturbations on predictive ability (Gowen et al., 2011b).

By joining FTIR spectroscopy with two dimensional correlation analysis (2DCORR) there will be obtained a device with improved performance in the study of complex environmental systems (Noda and Ozaki, 2005). The two dimensional correlation analysis (2DCORR) is a method to visualize the dynamic relationship between the variables in multivariate data set with application of the complex cross-correlation function. With the help of this analysis there will be identified the spectral features which change in phase (i.e. linearly correlated among them) and out of phase (partially or not at all correlated among them) (Mecozzi *et al*., 2009). This technique can be applied to study the evolution of environmental complex systems. Mecozzi and coworkers applied FTIR spectroscopy joined with two dimensional correlation analysis (2DCORR) to identify the aggregation pathways of extractable humic substance from marine sediments, and to compare the molecular modifications determined by the actions of different pollutants on the marine algae *Dunaliella tertiolecta* that is a biomarker of environmental quality (Mecozzi *et al*., 2009). From this study it can be concluded that FTIR spectroscopy joined with 2DCORR analysis can be an important tool for evaluating toxic effects on the marine life.
