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 . .

TY  - JOUR
AU  - Tomić, Zorica
AU  - Antić-Mladenović, Svetlana
AU  - Babić, Biljana M.
AU  - Poharc-Logar, Vesna A.
AU  - Djordjević, Aleksandar
AU  - Cupać, Svjetlana
PY  - 2011
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2565
AB  - Bentonite samples from Petrovac and Aleksinac were treated with sulfuric acid of different molarities. Differences in structure and texture of the initial and modified bentonite were determined by chemical analysis and Xraypowder diffraction (XRPD), infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and physisorption nitrogen at -196°C. Sulfuric acid caused an exchange of Al3+, Fe3+ and Mg2+ with H+ ions which led to a modification of the smectite crystalline structure. The Mg and Fe substitution in the octahedral sheet promoted the dispersion of those layers and forming of amorphous silicon. The sequence according to which the cations left the octahedral sheets was as follows: Mg2+>Fe3+>Al3+. The sulfuric acid activated bentonites exhibiting a lower cation exchange capacity (CEC) and a change of specific surface area (SBET) from 6 to 387 for bentonite from Petrovac and from 44 to 1784 m2 g-1 for bentonite from Aleksinac, positioning them as an excellent absorber in wine technology and in the protection of soil and environment.
AB  - Uzorci bentonita iz Petrovca i Aleksinca tretirani su različitim molaritetima sumporne kiseline. Promene u strukturi i teksturi polaznih i modifikovanih bentonita utvrđene su hemijskom i analizom rendgenske difrakcije praha X-zraka (XRPD), infra crvenom spektroskopijom (FTIR), skening elektronskom mikroskopijom (SEM) i fizisorpcijom azota na -196°C. Dejstvo H2SO4 kiseline izazvalo je zamenu Al3+, Fe3+ i Mg2+ sa H+ jonima što je dovelo do modifikacije kristalne strukture smektita. Supstitucija Mg i Fe u oktaedarskom listu smektita promovisala je raspuštanje tih slojeva i formiranje silikatne faze. Redosled kojim su ovi katjoni napuštali oktaedarske listove bio je sledeći: Mg2+>Fe3+>Al3+. Sumpornom kiselinom aktivirani bentoniti pokazali su niži kapacitet katjonske izmene (CEC) i promenu specifične površine (SBET), od 6 na 387 kod bentonita Petrovca i od 44 na 1784 m2 g-1 kod bentonita Aleksinca, što ih svrstava u odlične absorbente u tehnologiji vina, zaštiti zemljišta i životne sredine.
PB  - Univerzitet u Beogradu - Poljoprivredni fakultet, Beograd
T2  - Journal of Agricultural Sciences (Belgrade)
T1  - Modification of smectite structure by sulfuric acid and characteristics of the modified smectite
T1  - Modifikacija strukture smektita sumpornom kiselinom i karakteristike modifikovanih smektita
EP  - 35
IS  - 1
SP  - 25
VL  - 56
DO  - 10.2298/JAS1101025T
ER  - 

@article{
author = "Tomić, Zorica and Antić-Mladenović, Svetlana and Babić, Biljana M. and Poharc-Logar, Vesna A. and Djordjević, Aleksandar and Cupać, Svjetlana",
year = "2011",
abstract = "Bentonite samples from Petrovac and Aleksinac were treated with sulfuric acid of different molarities. Differences in structure and texture of the initial and modified bentonite were determined by chemical analysis and Xraypowder diffraction (XRPD), infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and physisorption nitrogen at -196°C. Sulfuric acid caused an exchange of Al3+, Fe3+ and Mg2+ with H+ ions which led to a modification of the smectite crystalline structure. The Mg and Fe substitution in the octahedral sheet promoted the dispersion of those layers and forming of amorphous silicon. The sequence according to which the cations left the octahedral sheets was as follows: Mg2+>Fe3+>Al3+. The sulfuric acid activated bentonites exhibiting a lower cation exchange capacity (CEC) and a change of specific surface area (SBET) from 6 to 387 for bentonite from Petrovac and from 44 to 1784 m2 g-1 for bentonite from Aleksinac, positioning them as an excellent absorber in wine technology and in the protection of soil and environment., Uzorci bentonita iz Petrovca i Aleksinca tretirani su različitim molaritetima sumporne kiseline. Promene u strukturi i teksturi polaznih i modifikovanih bentonita utvrđene su hemijskom i analizom rendgenske difrakcije praha X-zraka (XRPD), infra crvenom spektroskopijom (FTIR), skening elektronskom mikroskopijom (SEM) i fizisorpcijom azota na -196°C. Dejstvo H2SO4 kiseline izazvalo je zamenu Al3+, Fe3+ i Mg2+ sa H+ jonima što je dovelo do modifikacije kristalne strukture smektita. Supstitucija Mg i Fe u oktaedarskom listu smektita promovisala je raspuštanje tih slojeva i formiranje silikatne faze. Redosled kojim su ovi katjoni napuštali oktaedarske listove bio je sledeći: Mg2+>Fe3+>Al3+. Sumpornom kiselinom aktivirani bentoniti pokazali su niži kapacitet katjonske izmene (CEC) i promenu specifične površine (SBET), od 6 na 387 kod bentonita Petrovca i od 44 na 1784 m2 g-1 kod bentonita Aleksinca, što ih svrstava u odlične absorbente u tehnologiji vina, zaštiti zemljišta i životne sredine.",
publisher = "Univerzitet u Beogradu - Poljoprivredni fakultet, Beograd",
journal = "Journal of Agricultural Sciences (Belgrade)",
title = "Modification of smectite structure by sulfuric acid and characteristics of the modified smectite, Modifikacija strukture smektita sumpornom kiselinom i karakteristike modifikovanih smektita",
pages = "35-25",
number = "1",
volume = "56",
doi = "10.2298/JAS1101025T"
}

Tomić, Z., Antić-Mladenović, S., Babić, B. M., Poharc-Logar, V. A., Djordjević, A.,& Cupać, S.. (2011). Modification of smectite structure by sulfuric acid and characteristics of the modified smectite. in Journal of Agricultural Sciences (Belgrade)
Univerzitet u Beogradu - Poljoprivredni fakultet, Beograd., 56(1), 25-35.
https://doi.org/10.2298/JAS1101025T

Tomić Z, Antić-Mladenović S, Babić BM, Poharc-Logar VA, Djordjević A, Cupać S. Modification of smectite structure by sulfuric acid and characteristics of the modified smectite. in Journal of Agricultural Sciences (Belgrade). 2011;56(1):25-35.
doi:10.2298/JAS1101025T .

Tomić, Zorica, Antić-Mladenović, Svetlana, Babić, Biljana M., Poharc-Logar, Vesna A., Djordjević, Aleksandar, Cupać, Svjetlana, "Modification of smectite structure by sulfuric acid and characteristics of the modified smectite" in Journal of Agricultural Sciences (Belgrade), 56, no. 1 (2011):25-35,
https://doi.org/10.2298/JAS1101025T . .