Near-infrared (NIR) and mid-infrared (MIR) spectroscopy are irreplaceable methods for characterization of bentonites. The paper presents work on bentonites modified with inorganic Na+ and organic HDTMA(+) (hexaclecyltrimethylammonium) cations and treated by 1.5, 3, 4.5 and 6M H2SO4. The characterization was based on the assignment of the stretching (nu) and bending (delta) vibrations observed in the MIR region and the first overtone [2 nu(R-H)] and combination [nu(R-H)+delta(R-H)] modes of R-H groups (R=O, C) in the NIR region. NIR spectrum shows the characteristic OH and CH bonds for organomontmorillonite. The effect of larger alkylammonium cations on the vibrations of Si-O and OH bonds in montmorillonite layers is observed. A few key-bands in the NIR region show the change of water in the interlayer montmorillonite. The intensities of the overtone (7080 and 6840cm(-1)) and combination (5242cm(-1)) bands of H2O have considerably decreased as a result of hydrophobic character of the Na...OM. Spectra of acid-treated samples show a gradual decrease in the intensities of the OH overtone (near 7100-7000cm(-1)) and combination bands (4600-4300cm(-1)) reflecting a fewer number of octahedral atoms. This paper also points out that ATR technique and the 2nd derivative spectrum enables much precise band assignment.
TY - JOUR
AU - Tomić, Zorica
AU - Ašanin, Darko P.
AU - Antić-Mladenović, Svetlana
AU - Poharc-Logar, Vesna
AU - Makreski, Petre
PY - 2012
UR - http://aspace.agrif.bg.ac.rs/handle/123456789/3028
AB - Near-infrared (NIR) and mid-infrared (MIR) spectroscopy are irreplaceable methods for characterization of bentonites. The paper presents work on bentonites modified with inorganic Na+ and organic HDTMA(+) (hexaclecyltrimethylammonium) cations and treated by 1.5, 3, 4.5 and 6M H2SO4. The characterization was based on the assignment of the stretching (nu) and bending (delta) vibrations observed in the MIR region and the first overtone [2 nu(R-H)] and combination [nu(R-H)+delta(R-H)] modes of R-H groups (R=O, C) in the NIR region. NIR spectrum shows the characteristic OH and CH bonds for organomontmorillonite. The effect of larger alkylammonium cations on the vibrations of Si-O and OH bonds in montmorillonite layers is observed. A few key-bands in the NIR region show the change of water in the interlayer montmorillonite. The intensities of the overtone (7080 and 6840cm(-1)) and combination (5242cm(-1)) bands of H2O have considerably decreased as a result of hydrophobic character of the NaOM. Spectra of acid-treated samples show a gradual decrease in the intensities of the OH overtone (near 7100-7000cm(-1)) and combination bands (4600-4300cm(-1)) reflecting a fewer number of octahedral atoms. This paper also points out that ATR technique and the 2nd derivative spectrum enables much precise band assignment.
PB - Elsevier, Amsterdam
T2 - Vibrational Spectroscopy
T1 - NIR and MIR spectroscopic characteristics of hydrophilic and hydrophobic bentonite treated with sulphuric acid
EP - 103
SP - 95
VL - 58
DO - 10.1016/j.vibspec.2011.11.002
ER -
@article{
author = "Tomić, Zorica and Ašanin, Darko P. and Antić-Mladenović, Svetlana and Poharc-Logar, Vesna and Makreski, Petre",
year = "2012",
abstract = "Near-infrared (NIR) and mid-infrared (MIR) spectroscopy are irreplaceable methods for characterization of bentonites. The paper presents work on bentonites modified with inorganic Na+ and organic HDTMA(+) (hexaclecyltrimethylammonium) cations and treated by 1.5, 3, 4.5 and 6M H2SO4. The characterization was based on the assignment of the stretching (nu) and bending (delta) vibrations observed in the MIR region and the first overtone [2 nu(R-H)] and combination [nu(R-H)+delta(R-H)] modes of R-H groups (R=O, C) in the NIR region. NIR spectrum shows the characteristic OH and CH bonds for organomontmorillonite. The effect of larger alkylammonium cations on the vibrations of Si-O and OH bonds in montmorillonite layers is observed. A few key-bands in the NIR region show the change of water in the interlayer montmorillonite. The intensities of the overtone (7080 and 6840cm(-1)) and combination (5242cm(-1)) bands of H2O have considerably decreased as a result of hydrophobic character of the NaOM. Spectra of acid-treated samples show a gradual decrease in the intensities of the OH overtone (near 7100-7000cm(-1)) and combination bands (4600-4300cm(-1)) reflecting a fewer number of octahedral atoms. This paper also points out that ATR technique and the 2nd derivative spectrum enables much precise band assignment.",
publisher = "Elsevier, Amsterdam",
journal = "Vibrational Spectroscopy",
title = "NIR and MIR spectroscopic characteristics of hydrophilic and hydrophobic bentonite treated with sulphuric acid",
pages = "103-95",
volume = "58",
doi = "10.1016/j.vibspec.2011.11.002"
}
Tomić, Z., Ašanin, D. P., Antić-Mladenović, S., Poharc-Logar, V.,& Makreski, P.. (2012). NIR and MIR spectroscopic characteristics of hydrophilic and hydrophobic bentonite treated with sulphuric acid. in Vibrational Spectroscopy
Elsevier, Amsterdam., 58, 95-103.
https://doi.org/10.1016/j.vibspec.2011.11.002
Tomić Z, Ašanin DP, Antić-Mladenović S, Poharc-Logar V, Makreski P. NIR and MIR spectroscopic characteristics of hydrophilic and hydrophobic bentonite treated with sulphuric acid. in Vibrational Spectroscopy. 2012;58:95-103.
doi:10.1016/j.vibspec.2011.11.002 .
Tomić, Zorica, Ašanin, Darko P., Antić-Mladenović, Svetlana, Poharc-Logar, Vesna, Makreski, Petre, "NIR and MIR spectroscopic characteristics of hydrophilic and hydrophobic bentonite treated with sulphuric acid" in Vibrational Spectroscopy, 58 (2012):95-103,
https://doi.org/10.1016/j.vibspec.2011.11.002 . .
