TY  - JOUR
AU  - Marjanović, Vesna
AU  - Lazarević, Slavica
AU  - Janković-Častvan, Ivona
AU  - Potkonjak, Branislav
AU  - Janaćković, Đorđe
AU  - Petrović, Radomir
PY  - 2011
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4085
AB  - Natural and acid-activated sepiolite samples were functionalized with (3-Mercaptopropyl)trimethoxysilane.
By X-ray powder diffraction, Fourier transform infrared spectroscopy, and differential thermal
analysis it was shown that functionalization of sepiolites by grafting silane reagents occurs mainly on
the surface, whereby their crystalline structure remained unchanged. The efficiency of the adsorbents
in Cr(VI) removal from aqueous solutions follows the order: functionalized acid-activated sepiolite
> functionalized natural sepiolite > acid-activated sepiolite > natural sepiolite. As the number of silanol
groups on the sepiolite surface increased during the acid activation, the silane functionalization increased
and this led to an increase in Cr(VI) adsorption. The adsorption capacity strongly depended on the pH
of the solution from which the adsorption occurred. Maximum Cr(VI) removal was ca. 8.0mg Cr(VI) per
g of functionalized acid-activated sepiolite at initial pH 3, when the pH of solution reached 4.7, and
ca. 2.7mg Cr(VI) per g of functionalized natural sepiolite at initial pH 2, when the pH of the solution
reached 2.5. Cr(VI) removal by the functionalized sepiolites was mainly attributed to electrostatic attraction
between the protonated mercapto groups and the negatively charged Cr(VI) species. The sorption
isotherms showed that Cr(VI) removal by both functionalized sepiolites for all initial investigated solution
pH values is well described using the Dubinin–Radushkevich model. The thermodynamic data suggest
spontaneity of the major physical adsorption process at 298 K.
PB  - Elsevier
T2  - Chemical Engineering Journal
T1  - Chromium (VI) removal from aqueous solutions using mercaptosilane functionalized sepiolites
VL  - 166
IS  - 1
SP  - 198
EP  - 206
DO  - 10.1016/j.cej.2010.10.062
ER  - 

@article{
author = "Marjanović, Vesna and Lazarević, Slavica and Janković-Častvan, Ivona and Potkonjak, Branislav and Janaćković, Đorđe and Petrović, Radomir",
year = "2011",
abstract = "Natural and acid-activated sepiolite samples were functionalized with (3-Mercaptopropyl)trimethoxysilane.
By X-ray powder diffraction, Fourier transform infrared spectroscopy, and differential thermal
analysis it was shown that functionalization of sepiolites by grafting silane reagents occurs mainly on
the surface, whereby their crystalline structure remained unchanged. The efficiency of the adsorbents
in Cr(VI) removal from aqueous solutions follows the order: functionalized acid-activated sepiolite
> functionalized natural sepiolite > acid-activated sepiolite > natural sepiolite. As the number of silanol
groups on the sepiolite surface increased during the acid activation, the silane functionalization increased
and this led to an increase in Cr(VI) adsorption. The adsorption capacity strongly depended on the pH
of the solution from which the adsorption occurred. Maximum Cr(VI) removal was ca. 8.0mg Cr(VI) per
g of functionalized acid-activated sepiolite at initial pH 3, when the pH of solution reached 4.7, and
ca. 2.7mg Cr(VI) per g of functionalized natural sepiolite at initial pH 2, when the pH of the solution
reached 2.5. Cr(VI) removal by the functionalized sepiolites was mainly attributed to electrostatic attraction
between the protonated mercapto groups and the negatively charged Cr(VI) species. The sorption
isotherms showed that Cr(VI) removal by both functionalized sepiolites for all initial investigated solution
pH values is well described using the Dubinin–Radushkevich model. The thermodynamic data suggest
spontaneity of the major physical adsorption process at 298 K.",
publisher = "Elsevier",
journal = "Chemical Engineering Journal",
title = "Chromium (VI) removal from aqueous solutions using mercaptosilane functionalized sepiolites",
volume = "166",
number = "1",
pages = "198-206",
doi = "10.1016/j.cej.2010.10.062"
}

Marjanović, V., Lazarević, S., Janković-Častvan, I., Potkonjak, B., Janaćković, Đ.,& Petrović, R.. (2011). Chromium (VI) removal from aqueous solutions using mercaptosilane functionalized sepiolites. in Chemical Engineering Journal
Elsevier., 166(1), 198-206.
https://doi.org/10.1016/j.cej.2010.10.062

Marjanović V, Lazarević S, Janković-Častvan I, Potkonjak B, Janaćković Đ, Petrović R. Chromium (VI) removal from aqueous solutions using mercaptosilane functionalized sepiolites. in Chemical Engineering Journal. 2011;166(1):198-206.
doi:10.1016/j.cej.2010.10.062 .

Marjanović, Vesna, Lazarević, Slavica, Janković-Častvan, Ivona, Potkonjak, Branislav, Janaćković, Đorđe, Petrović, Radomir, "Chromium (VI) removal from aqueous solutions using mercaptosilane functionalized sepiolites" in Chemical Engineering Journal, 166, no. 1 (2011):198-206,
https://doi.org/10.1016/j.cej.2010.10.062 . .

TY  - JOUR
AU  - Jokić, Bojan
AU  - Drmanić, Saša Ž.
AU  - Radetić, Tamara
AU  - Krstić, Jugoslav
AU  - Petrovic, R.
AU  - Orlovic, A.
AU  - Janaćković, Đorđe
PY  - 2010
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/715
AB  - Submicron carbon spherical particles were obtained by polycondensation of resorcinol and formaldehyde in a solution and subsequent ultrasonic spray pyrolysis of the prepared sol. Microscopic characterization indicates the regular spherical shape of the obtained particles and sphere diameters in 200-700 nm range. The carbon spheres are amorphous as confirmed by electron diffraction, EELS, XRD and HREM characterization. Activation procedure was performed with H2O in a nitrogen flow for 15 and 30 min at 800 degrees C. The activation procedure preserved the initial spherical shapes of the particles while the particle porosity and specific surface area were increased. The amount of surface oxygen functionalities was also increased by activation procedure as indicated by FTIR analysis.
PB  - Elsevier
T2  - Materials Letters
T1  - Synthesis of submicron carbon spheres by the ultrasonic spray pyrolysis method
VL  - 64
IS  - 20
SP  - 2173
EP  - 2176
DO  - 10.1016/j.matlet.2010.06.066
ER  - 

@article{
author = "Jokić, Bojan and Drmanić, Saša Ž. and Radetić, Tamara and Krstić, Jugoslav and Petrovic, R. and Orlovic, A. and Janaćković, Đorđe",
year = "2010",
abstract = "Submicron carbon spherical particles were obtained by polycondensation of resorcinol and formaldehyde in a solution and subsequent ultrasonic spray pyrolysis of the prepared sol. Microscopic characterization indicates the regular spherical shape of the obtained particles and sphere diameters in 200-700 nm range. The carbon spheres are amorphous as confirmed by electron diffraction, EELS, XRD and HREM characterization. Activation procedure was performed with H2O in a nitrogen flow for 15 and 30 min at 800 degrees C. The activation procedure preserved the initial spherical shapes of the particles while the particle porosity and specific surface area were increased. The amount of surface oxygen functionalities was also increased by activation procedure as indicated by FTIR analysis.",
publisher = "Elsevier",
journal = "Materials Letters",
title = "Synthesis of submicron carbon spheres by the ultrasonic spray pyrolysis method",
volume = "64",
number = "20",
pages = "2173-2176",
doi = "10.1016/j.matlet.2010.06.066"
}

Jokić, B., Drmanić, S. Ž., Radetić, T., Krstić, J., Petrovic, R., Orlovic, A.,& Janaćković, Đ.. (2010). Synthesis of submicron carbon spheres by the ultrasonic spray pyrolysis method. in Materials Letters
Elsevier., 64(20), 2173-2176.
https://doi.org/10.1016/j.matlet.2010.06.066

Jokić B, Drmanić SŽ, Radetić T, Krstić J, Petrovic R, Orlovic A, Janaćković Đ. Synthesis of submicron carbon spheres by the ultrasonic spray pyrolysis method. in Materials Letters. 2010;64(20):2173-2176.
doi:10.1016/j.matlet.2010.06.066 .

Jokić, Bojan, Drmanić, Saša Ž., Radetić, Tamara, Krstić, Jugoslav, Petrovic, R., Orlovic, A., Janaćković, Đorđe, "Synthesis of submicron carbon spheres by the ultrasonic spray pyrolysis method" in Materials Letters, 64, no. 20 (2010):2173-2176,
https://doi.org/10.1016/j.matlet.2010.06.066 . .

TY  - JOUR
AU  - Tanaskovic, N.
AU  - Radovanović, Z.
AU  - Dokic, V.
AU  - Krstić, Jugoslav
AU  - Drmanić, Saša Ž.
AU  - Janaćković, Đorđe
AU  - Petrovic, R.
PY  - 2009
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/527
AB  - Mesoporous titania with well-crystallized anatase phase was synthesized by nonhydrolytic sol-gel process combined with solvothermal treatment. Titanium-isopropoxide, titanium-tetrachloride, and carbon-tetrachloride were used for synthesis under nitrogen atmosphere in a glove box. The obtained mixture was heated in an autoclave at 140 degrees C for 3 h and 30 h. XRD analysis showed that dry gels contained anatase phase with low crystallinity, while powders obtained by calcination of dry gels at 500 degrees C for 3 h consisted of pure anatase with high crystallinity. SEM analysis of dried gels and powders shows agglomerates of spherical particles of the size similar to 300 nm. The TEM micrographs confirmed the nanoscale size of the titania powders, with the primary particle size of about 20 nm. Titania powders exhibit maximum pore diameter of 13.2 nm and 9.5 nm for gelation time 3 h and 30 h, respectively. The photocatalytic activity of such synthesized titania is superior to that of commercial photocatalyst Degussa P-25.
PB  - Academic Press Ltd- Elsevier Science Ltd, London
T2  - Superlattices and Microstructures
T1  - Synthesis of mesoporous nanocrystalline titania powders by nonhydrolitic sol-gel method
VL  - 46
IS  - 1-2
SP  - 217
EP  - 222
DO  - 10.1016/j.spmi.2008.12.028
ER  - 

@article{
author = "Tanaskovic, N. and Radovanović, Z. and Dokic, V. and Krstić, Jugoslav and Drmanić, Saša Ž. and Janaćković, Đorđe and Petrovic, R.",
year = "2009",
abstract = "Mesoporous titania with well-crystallized anatase phase was synthesized by nonhydrolytic sol-gel process combined with solvothermal treatment. Titanium-isopropoxide, titanium-tetrachloride, and carbon-tetrachloride were used for synthesis under nitrogen atmosphere in a glove box. The obtained mixture was heated in an autoclave at 140 degrees C for 3 h and 30 h. XRD analysis showed that dry gels contained anatase phase with low crystallinity, while powders obtained by calcination of dry gels at 500 degrees C for 3 h consisted of pure anatase with high crystallinity. SEM analysis of dried gels and powders shows agglomerates of spherical particles of the size similar to 300 nm. The TEM micrographs confirmed the nanoscale size of the titania powders, with the primary particle size of about 20 nm. Titania powders exhibit maximum pore diameter of 13.2 nm and 9.5 nm for gelation time 3 h and 30 h, respectively. The photocatalytic activity of such synthesized titania is superior to that of commercial photocatalyst Degussa P-25.",
publisher = "Academic Press Ltd- Elsevier Science Ltd, London",
journal = "Superlattices and Microstructures",
title = "Synthesis of mesoporous nanocrystalline titania powders by nonhydrolitic sol-gel method",
volume = "46",
number = "1-2",
pages = "217-222",
doi = "10.1016/j.spmi.2008.12.028"
}

Tanaskovic, N., Radovanović, Z., Dokic, V., Krstić, J., Drmanić, S. Ž., Janaćković, Đ.,& Petrovic, R.. (2009). Synthesis of mesoporous nanocrystalline titania powders by nonhydrolitic sol-gel method. in Superlattices and Microstructures
Academic Press Ltd- Elsevier Science Ltd, London., 46(1-2), 217-222.
https://doi.org/10.1016/j.spmi.2008.12.028

Tanaskovic N, Radovanović Z, Dokic V, Krstić J, Drmanić SŽ, Janaćković Đ, Petrovic R. Synthesis of mesoporous nanocrystalline titania powders by nonhydrolitic sol-gel method. in Superlattices and Microstructures. 2009;46(1-2):217-222.
doi:10.1016/j.spmi.2008.12.028 .

Tanaskovic, N., Radovanović, Z., Dokic, V., Krstić, Jugoslav, Drmanić, Saša Ž., Janaćković, Đorđe, Petrovic, R., "Synthesis of mesoporous nanocrystalline titania powders by nonhydrolitic sol-gel method" in Superlattices and Microstructures, 46, no. 1-2 (2009):217-222,
https://doi.org/10.1016/j.spmi.2008.12.028 . .

TY  - JOUR
AU  - Lazarević, Slavica
AU  - Janković-Častvan, Ivona
AU  - Jovanović, Dušan
AU  - Milonjić, Slobodan
AU  - Janaćković, Đorđe
AU  - Petrović, Rada
PY  - 2007
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4122
AB  - The adsorption mechanisms of Pb2+, Cd2+ and Sr2+ ions on natural sepiolite and the influence of acid treatment on the adsorption capacity of sepiolite were investigated. The point of zero charge, pHpzc, is 7.4 ± 0.1 for natural sepiolite and 6.9 ± 0.1 for partially acid-activated sepiolite. The shift of the pHpzc of sepiolites toward lower pH values in solutions of Pb2+ and Cd2+ ions indicates that specific adsorption of these cations on natural and acid-activated sepiolites occurred, which was more pronounced for Pb2+ ions than for Cd2+ ions. There was no shift of the pHpzc in solution containing Sr2+ ions, suggesting that specific adsorption of this cation did not occur. The affinity for ion exchange with the Mg2+ ions from the sepiolite structure was the highest for Pb2+ ions, then Cd2+, whereas the affinity for Sr2+ ions was negligible. The adsorption isotherms suggest that the sequence of the efficiency of the sepiolites adsorption is Pb2+ > Cd2+ > Sr2+. The retention of Pb2+ and Cd2+ ions by sepiolite occurs dominantly by specific adsorption and exchange of Mg2+ ions from the sepiolite structure. The concentration in the external outer sphere of the Stern layer by electrostatic forces is the dominant mechanism for the retention of Sr2+ ions on the surface of sepiolites. Despite increases in the surface areas upon acid activation, improvements in the adsorption were not observed, as a result of the decreasing number of Mg-OH groups, as main centers for specific adsorption, and the number of Mg2+ ions available for ion exchange with Pb2+, Cd2+ and Sr2+ ions. The removal of Mg-OH groups from the sepiolite also resulted in a decrease in the point of zero charge and an increase of the relative surface acidity, from 2.6 ± 0.1 for the natural to 6.4 ± 0.1 for the acid-activated sepiolite.
PB  - Elsevier
T2  - Applied Clay Science
T1  - Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites
VL  - 37
IS  - 1-2
SP  - 47
EP  - 57
DO  - 10.1016/j.clay.2006.11.008
ER  - 

@article{
author = "Lazarević, Slavica and Janković-Častvan, Ivona and Jovanović, Dušan and Milonjić, Slobodan and Janaćković, Đorđe and Petrović, Rada",
year = "2007",
abstract = "The adsorption mechanisms of Pb2+, Cd2+ and Sr2+ ions on natural sepiolite and the influence of acid treatment on the adsorption capacity of sepiolite were investigated. The point of zero charge, pHpzc, is 7.4 ± 0.1 for natural sepiolite and 6.9 ± 0.1 for partially acid-activated sepiolite. The shift of the pHpzc of sepiolites toward lower pH values in solutions of Pb2+ and Cd2+ ions indicates that specific adsorption of these cations on natural and acid-activated sepiolites occurred, which was more pronounced for Pb2+ ions than for Cd2+ ions. There was no shift of the pHpzc in solution containing Sr2+ ions, suggesting that specific adsorption of this cation did not occur. The affinity for ion exchange with the Mg2+ ions from the sepiolite structure was the highest for Pb2+ ions, then Cd2+, whereas the affinity for Sr2+ ions was negligible. The adsorption isotherms suggest that the sequence of the efficiency of the sepiolites adsorption is Pb2+ > Cd2+ > Sr2+. The retention of Pb2+ and Cd2+ ions by sepiolite occurs dominantly by specific adsorption and exchange of Mg2+ ions from the sepiolite structure. The concentration in the external outer sphere of the Stern layer by electrostatic forces is the dominant mechanism for the retention of Sr2+ ions on the surface of sepiolites. Despite increases in the surface areas upon acid activation, improvements in the adsorption were not observed, as a result of the decreasing number of Mg-OH groups, as main centers for specific adsorption, and the number of Mg2+ ions available for ion exchange with Pb2+, Cd2+ and Sr2+ ions. The removal of Mg-OH groups from the sepiolite also resulted in a decrease in the point of zero charge and an increase of the relative surface acidity, from 2.6 ± 0.1 for the natural to 6.4 ± 0.1 for the acid-activated sepiolite.",
publisher = "Elsevier",
journal = "Applied Clay Science",
title = "Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites",
volume = "37",
number = "1-2",
pages = "47-57",
doi = "10.1016/j.clay.2006.11.008"
}

Lazarević, S., Janković-Častvan, I., Jovanović, D., Milonjić, S., Janaćković, Đ.,& Petrović, R.. (2007). Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites. in Applied Clay Science
Elsevier., 37(1-2), 47-57.
https://doi.org/10.1016/j.clay.2006.11.008

Lazarević S, Janković-Častvan I, Jovanović D, Milonjić S, Janaćković Đ, Petrović R. Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites. in Applied Clay Science. 2007;37(1-2):47-57.
doi:10.1016/j.clay.2006.11.008 .

Lazarević, Slavica, Janković-Častvan, Ivona, Jovanović, Dušan, Milonjić, Slobodan, Janaćković, Đorđe, Petrović, Rada, "Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites" in Applied Clay Science, 37, no. 1-2 (2007):47-57,
https://doi.org/10.1016/j.clay.2006.11.008 . .