TY  - JOUR
AU  - Milovanović, Željka
AU  - Lazarević, Slavica
AU  - Janković-Častvan, Ivona
AU  - Radovanović, Željko
AU  - Cvetković, Slobodan
AU  - Janaćković, Đorđe
AU  - Petrović, Rada
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6578
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7169
AB  - The sepiolite/ZrO2 composites were prepared by sepiolite (Sep) modification with zirconium propoxide in toluene at room temperature for 24 h (Sep–ZrI) or 95 °C for 4 h (sample Sep–ZrII). The efficiency of the obtained composites for the removal of phosphate from aqueous solutions at initial pH = 4 and pH = 8 was investigated. Characterization of the samples shows that synthesis at a higher temperature for a shorter time provides a slightly higher content of amorphous Zr phase, which is deposited on the sepiolite fibers as a thin layer and agglomerated nanoparticles. Compared to Sep, the composites have a lower point of zero charge and higher specific surface area and pore volume. The adsorption kinetics follow the pseudo second-order model. The adsorption capacities of the composites are approximately the same at both initial pH and higher at initial pH = 4 than at pH = 8. The XPS and ATR-FTIR of Sep–ZrI before and after adsorption identifies the formation of inner-sphere complexes as the mechanism of phosphate adsorption. The slow release during desorption with NaOH solution confirms the strong bonds of the phosphates with the surface of the composites.
PB  - MDPI
T2  - Water
T1  - The Removal of Phosphate from Aqueous Solutions by Sepiolite/ZrO2 Composites: Adsorption Behavior and Mechanism
VL  - 15
IS  - 13
SP  - 2376
DO  - 10.3390/w15132376
ER  - 

@article{
author = "Milovanović, Željka and Lazarević, Slavica and Janković-Častvan, Ivona and Radovanović, Željko and Cvetković, Slobodan and Janaćković, Đorđe and Petrović, Rada",
year = "2023",
abstract = "The sepiolite/ZrO2 composites were prepared by sepiolite (Sep) modification with zirconium propoxide in toluene at room temperature for 24 h (Sep–ZrI) or 95 °C for 4 h (sample Sep–ZrII). The efficiency of the obtained composites for the removal of phosphate from aqueous solutions at initial pH = 4 and pH = 8 was investigated. Characterization of the samples shows that synthesis at a higher temperature for a shorter time provides a slightly higher content of amorphous Zr phase, which is deposited on the sepiolite fibers as a thin layer and agglomerated nanoparticles. Compared to Sep, the composites have a lower point of zero charge and higher specific surface area and pore volume. The adsorption kinetics follow the pseudo second-order model. The adsorption capacities of the composites are approximately the same at both initial pH and higher at initial pH = 4 than at pH = 8. The XPS and ATR-FTIR of Sep–ZrI before and after adsorption identifies the formation of inner-sphere complexes as the mechanism of phosphate adsorption. The slow release during desorption with NaOH solution confirms the strong bonds of the phosphates with the surface of the composites.",
publisher = "MDPI",
journal = "Water",
title = "The Removal of Phosphate from Aqueous Solutions by Sepiolite/ZrO2 Composites: Adsorption Behavior and Mechanism",
volume = "15",
number = "13",
pages = "2376",
doi = "10.3390/w15132376"
}

Milovanović, Ž., Lazarević, S., Janković-Častvan, I., Radovanović, Ž., Cvetković, S., Janaćković, Đ.,& Petrović, R.. (2023). The Removal of Phosphate from Aqueous Solutions by Sepiolite/ZrO2 Composites: Adsorption Behavior and Mechanism. in Water
MDPI., 15(13), 2376.
https://doi.org/10.3390/w15132376

Milovanović Ž, Lazarević S, Janković-Častvan I, Radovanović Ž, Cvetković S, Janaćković Đ, Petrović R. The Removal of Phosphate from Aqueous Solutions by Sepiolite/ZrO2 Composites: Adsorption Behavior and Mechanism. in Water. 2023;15(13):2376.
doi:10.3390/w15132376 .

Milovanović, Željka, Lazarević, Slavica, Janković-Častvan, Ivona, Radovanović, Željko, Cvetković, Slobodan, Janaćković, Đorđe, Petrović, Rada, "The Removal of Phosphate from Aqueous Solutions by Sepiolite/ZrO2 Composites: Adsorption Behavior and Mechanism" in Water, 15, no. 13 (2023):2376,
https://doi.org/10.3390/w15132376 . .

TY  - JOUR
AU  - Petrović, Rada
AU  - Lazarević, Slavica
AU  - Janković-Častvan, Ivona
AU  - Matić, Tamara
AU  - Milivojević, Marija
AU  - Milošević, Dragana
AU  - Veljović, Đorđe
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5400
AB  - Kaolinite/illite (KUb) and sepiolite (SEP) clays were used to study Cr(III) adsorption removal from aqueous solutions so that they could be utilized after saturation for ceramic manufacturing. SEP had a larger specific surface area and a higher PZC than KUb. The removal of Cr(III) was evaluated using a batch equilibration procedure at pHi = 4 and pHi = 6. Fast removal kinetics were observed for both clays. Maximum removal capacity was determined by changing the concentration of Cr(III) while keeping the concentration of clay constant and by altering the amount of clay while keeping the concentration of Cr(III) constant. In all situations, SEP had greater capacity than KUb, and capacity was greater for both clays at higher pHi. Not only did the pHi impact the removal capacity and efficiency, but so did the pH during adsorption and the initial concentration of Cr(III). Because of the higher PZC, the pHf for SEP was higher for the same pHi. The higher the pH and Cr(III) concentration, the higher the probability of Cr(OH)3 precipitation and the higher the removal capacity. Dried saturated clays were uniaxially pressed and sintered at 1000 °C for 2 h. The densities of the sintered materials were nearly identical to those of pure clay-based materials, but the compressive strengths were higher, which is significant for the use of saturated clays as raw materials in ceramic manufacturing. Leaching of Cr from SEP-based material was significantly higher than from KUb-based material probably due to the presence of CaCO3 in the SEP.
PB  - Elsevier
T2  - Applied  Clay Sciences
T1  - Removal of trivalent chromium from aqueous solutions by natural clays: Valorization of saturated adsorbents as raw materials in ceramic manufacturing
VL  - 231
SP  - 106747
DO  - 10.1016/j.clay.2022.106747
ER  - 

@article{
author = "Petrović, Rada and Lazarević, Slavica and Janković-Častvan, Ivona and Matić, Tamara and Milivojević, Marija and Milošević, Dragana and Veljović, Đorđe",
year = "2023",
abstract = "Kaolinite/illite (KUb) and sepiolite (SEP) clays were used to study Cr(III) adsorption removal from aqueous solutions so that they could be utilized after saturation for ceramic manufacturing. SEP had a larger specific surface area and a higher PZC than KUb. The removal of Cr(III) was evaluated using a batch equilibration procedure at pHi = 4 and pHi = 6. Fast removal kinetics were observed for both clays. Maximum removal capacity was determined by changing the concentration of Cr(III) while keeping the concentration of clay constant and by altering the amount of clay while keeping the concentration of Cr(III) constant. In all situations, SEP had greater capacity than KUb, and capacity was greater for both clays at higher pHi. Not only did the pHi impact the removal capacity and efficiency, but so did the pH during adsorption and the initial concentration of Cr(III). Because of the higher PZC, the pHf for SEP was higher for the same pHi. The higher the pH and Cr(III) concentration, the higher the probability of Cr(OH)3 precipitation and the higher the removal capacity. Dried saturated clays were uniaxially pressed and sintered at 1000 °C for 2 h. The densities of the sintered materials were nearly identical to those of pure clay-based materials, but the compressive strengths were higher, which is significant for the use of saturated clays as raw materials in ceramic manufacturing. Leaching of Cr from SEP-based material was significantly higher than from KUb-based material probably due to the presence of CaCO3 in the SEP.",
publisher = "Elsevier",
journal = "Applied  Clay Sciences",
title = "Removal of trivalent chromium from aqueous solutions by natural clays: Valorization of saturated adsorbents as raw materials in ceramic manufacturing",
volume = "231",
pages = "106747",
doi = "10.1016/j.clay.2022.106747"
}

Petrović, R., Lazarević, S., Janković-Častvan, I., Matić, T., Milivojević, M., Milošević, D.,& Veljović, Đ.. (2023). Removal of trivalent chromium from aqueous solutions by natural clays: Valorization of saturated adsorbents as raw materials in ceramic manufacturing. in Applied  Clay Sciences
Elsevier., 231, 106747.
https://doi.org/10.1016/j.clay.2022.106747

Petrović R, Lazarević S, Janković-Častvan I, Matić T, Milivojević M, Milošević D, Veljović Đ. Removal of trivalent chromium from aqueous solutions by natural clays: Valorization of saturated adsorbents as raw materials in ceramic manufacturing. in Applied  Clay Sciences. 2023;231:106747.
doi:10.1016/j.clay.2022.106747 .

Petrović, Rada, Lazarević, Slavica, Janković-Častvan, Ivona, Matić, Tamara, Milivojević, Marija, Milošević, Dragana, Veljović, Đorđe, "Removal of trivalent chromium from aqueous solutions by natural clays: Valorization of saturated adsorbents as raw materials in ceramic manufacturing" in Applied  Clay Sciences, 231 (2023):106747,
https://doi.org/10.1016/j.clay.2022.106747 . .

TY  - JOUR
AU  - Milanović, Jovana Z.
AU  - Milošević, Milena D.
AU  - Janković-Častvan, Ivona
AU  - Kostić, Mirjana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4238
AB  - In this paper, the capillary rise and sorption ability of hemp fibers oxidized with hydrogen peroxide and potassium permanganate were studied, with the aim to get more insight into the changes in the structure of hemp fibers caused by oxidation, and to compare the influence of applied oxidative agents on hemp fibers. Capillary rise was presented as a function of a liquid rise height vs times, with determined all three capillary coefficients, while sorption ability was determined as water retention values and moisture sorption. For structural analysis of the samples the ATR-FTIR technique was used. Also, the amount of aldehyde and carboxyl groups and the lignin content in oxidized fibers were determined. The surface fibers morphology was observed by FESEM. In all oxidized hemp fibers an increase in capillarity was obtained for both oxidizing agents (33–75 mm for H2O2, and 40–114 mm for KMnO4), compared to 31 mm for unmodified fibers, but decreased sorption ability. Application of both oxidative agents, were successful for introduction of functional groups into oxidized fibers, for reduction of the amount of non-cellulosic substances, as well as moisture sorption. Simultaneously, the fibers became finer, cleaner, whiter, softer and more suitable for further processing, while, generally, higher influence on changes into oxidized hemp fibers was achieved by oxidation with KMnO4, compared to oxidation with H2O2.
PB  - USA :Taylor & Francis INC
T2  - Journal of Natural Fibers
T1  - Capillary rise and sorption ability of hemp fibers oxidized by non-selective oxidative agents: hydrogen peroxide and potassium permanganate
DO  - 10.1080/15440478.2020.1870609
ER  - 

@article{
author = "Milanović, Jovana Z. and Milošević, Milena D. and Janković-Častvan, Ivona and Kostić, Mirjana",
year = "2021",
abstract = "In this paper, the capillary rise and sorption ability of hemp fibers oxidized with hydrogen peroxide and potassium permanganate were studied, with the aim to get more insight into the changes in the structure of hemp fibers caused by oxidation, and to compare the influence of applied oxidative agents on hemp fibers. Capillary rise was presented as a function of a liquid rise height vs times, with determined all three capillary coefficients, while sorption ability was determined as water retention values and moisture sorption. For structural analysis of the samples the ATR-FTIR technique was used. Also, the amount of aldehyde and carboxyl groups and the lignin content in oxidized fibers were determined. The surface fibers morphology was observed by FESEM. In all oxidized hemp fibers an increase in capillarity was obtained for both oxidizing agents (33–75 mm for H2O2, and 40–114 mm for KMnO4), compared to 31 mm for unmodified fibers, but decreased sorption ability. Application of both oxidative agents, were successful for introduction of functional groups into oxidized fibers, for reduction of the amount of non-cellulosic substances, as well as moisture sorption. Simultaneously, the fibers became finer, cleaner, whiter, softer and more suitable for further processing, while, generally, higher influence on changes into oxidized hemp fibers was achieved by oxidation with KMnO4, compared to oxidation with H2O2.",
publisher = "USA :Taylor & Francis INC",
journal = "Journal of Natural Fibers",
title = "Capillary rise and sorption ability of hemp fibers oxidized by non-selective oxidative agents: hydrogen peroxide and potassium permanganate",
doi = "10.1080/15440478.2020.1870609"
}

Milanović, J. Z., Milošević, M. D., Janković-Častvan, I.,& Kostić, M.. (2021). Capillary rise and sorption ability of hemp fibers oxidized by non-selective oxidative agents: hydrogen peroxide and potassium permanganate. in Journal of Natural Fibers
USA :Taylor & Francis INC..
https://doi.org/10.1080/15440478.2020.1870609

Milanović JZ, Milošević MD, Janković-Častvan I, Kostić M. Capillary rise and sorption ability of hemp fibers oxidized by non-selective oxidative agents: hydrogen peroxide and potassium permanganate. in Journal of Natural Fibers. 2021;.
doi:10.1080/15440478.2020.1870609 .

Milanović, Jovana Z., Milošević, Milena D., Janković-Častvan, Ivona, Kostić, Mirjana, "Capillary rise and sorption ability of hemp fibers oxidized by non-selective oxidative agents: hydrogen peroxide and potassium permanganate" in Journal of Natural Fibers (2021),
https://doi.org/10.1080/15440478.2020.1870609 . .

TY  - JOUR
AU  - Milanović, Jovana Ž.
AU  - Milošević, Milena D.
AU  - Korica, Matea
AU  - Janković-Častvan, Ivona
AU  - Kostić, Mirjana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4528
AB  - Applications of hemp fibers, as a promising natural material in the textile field, mostly require improved fiber properties. In this paper, the oxidation of hemp fibers with potassium permanganate was applied to reduce the amount of noncellulosic substances and moisture sorption; to introduce functional groups and increase capillarity; make fibers finer, softer and suitable for application in sport wears. The changes in sorption properties were characterized by capillary rise measurement and the ability of water retention and moisture sorption, while changes in mechanical properties were estimated by determination of tenacity and elongation of modified hemp fibers in comparison to the appropriate characteristic of unmodified fibers. ATR-FTIR, SEM techniques, and zeta potential measurement were used for the characterization of fiber structure, morphological and electrokinetic properties. We obtained a finer fiber with increased capillarity (up to 3.68 times) but reduced moisture sorption (down to 1.5 times) and water retention capacity (down to 2.8 times), with accomplished satisfactory preservation of mechanical properties. Obtained oxidized hemp fibers with attained features present a very suitable material for sportswear production. Additionally, in this paper, an improvement of the capillary rise measurement is given.
PB  - Korean Fiber Society
T2  - Fibers and Polymers
T1  - Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear
DO  - 10.1007/s12221-021-0450-y
ER  - 

@article{
author = "Milanović, Jovana Ž. and Milošević, Milena D. and Korica, Matea and Janković-Častvan, Ivona and Kostić, Mirjana",
year = "2021",
abstract = "Applications of hemp fibers, as a promising natural material in the textile field, mostly require improved fiber properties. In this paper, the oxidation of hemp fibers with potassium permanganate was applied to reduce the amount of noncellulosic substances and moisture sorption; to introduce functional groups and increase capillarity; make fibers finer, softer and suitable for application in sport wears. The changes in sorption properties were characterized by capillary rise measurement and the ability of water retention and moisture sorption, while changes in mechanical properties were estimated by determination of tenacity and elongation of modified hemp fibers in comparison to the appropriate characteristic of unmodified fibers. ATR-FTIR, SEM techniques, and zeta potential measurement were used for the characterization of fiber structure, morphological and electrokinetic properties. We obtained a finer fiber with increased capillarity (up to 3.68 times) but reduced moisture sorption (down to 1.5 times) and water retention capacity (down to 2.8 times), with accomplished satisfactory preservation of mechanical properties. Obtained oxidized hemp fibers with attained features present a very suitable material for sportswear production. Additionally, in this paper, an improvement of the capillary rise measurement is given.",
publisher = "Korean Fiber Society",
journal = "Fibers and Polymers",
title = "Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear",
doi = "10.1007/s12221-021-0450-y"
}

Milanović, J. Ž., Milošević, M. D., Korica, M., Janković-Častvan, I.,& Kostić, M.. (2021). Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear. in Fibers and Polymers
Korean Fiber Society..
https://doi.org/10.1007/s12221-021-0450-y

Milanović JŽ, Milošević MD, Korica M, Janković-Častvan I, Kostić M. Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear. in Fibers and Polymers. 2021;.
doi:10.1007/s12221-021-0450-y .

Milanović, Jovana Ž., Milošević, Milena D., Korica, Matea, Janković-Častvan, Ivona, Kostić, Mirjana, "Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear" in Fibers and Polymers (2021),
https://doi.org/10.1007/s12221-021-0450-y . .

TY  - DATA
AU  - Milanović, Jovana Ž.
AU  - Milošević, Milena D.
AU  - Korica, Matea
AU  - Janković-Častvan, Ivona
AU  - Kostić, Mirjana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4529
AB  - S1. Capillary rise measurement: Section: Material and methods; S2 Structural and chemical changes in hemp fibers caused by oxidation process; S3 Deconvolution of the FTIR spectra; S4. Capillary rise and wettability parameters D, C and RS5. Mechanical properties – tenacity and elongation. Additional references.;
PB  - Korean Fiber Society
T2  - Fibers and Polymers
T1  - Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear
UR  - https://hdl.handle.net/21.15107/rcub_cer_4529
ER  - 

@misc{
author = "Milanović, Jovana Ž. and Milošević, Milena D. and Korica, Matea and Janković-Častvan, Ivona and Kostić, Mirjana",
year = "2021",
abstract = "S1. Capillary rise measurement: Section: Material and methods; S2 Structural and chemical changes in hemp fibers caused by oxidation process; S3 Deconvolution of the FTIR spectra; S4. Capillary rise and wettability parameters D, C and RS5. Mechanical properties – tenacity and elongation. Additional references.;",
publisher = "Korean Fiber Society",
journal = "Fibers and Polymers",
title = "Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear",
url = "https://hdl.handle.net/21.15107/rcub_cer_4529"
}

Milanović, J. Ž., Milošević, M. D., Korica, M., Janković-Častvan, I.,& Kostić, M.. (2021). Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear. in Fibers and Polymers
Korean Fiber Society..
https://hdl.handle.net/21.15107/rcub_cer_4529

Milanović JŽ, Milošević MD, Korica M, Janković-Častvan I, Kostić M. Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear. in Fibers and Polymers. 2021;.
https://hdl.handle.net/21.15107/rcub_cer_4529 .

Milanović, Jovana Ž., Milošević, Milena D., Korica, Matea, Janković-Častvan, Ivona, Kostić, Mirjana, "Oxidized Hemp Fibers with Simultaneously Increased Capillarity and Reduced Moisture Sorption as Suitable Textile Material for Advanced Application in Sportswear" in Fibers and Polymers (2021),
https://hdl.handle.net/21.15107/rcub_cer_4529 .

TY  - JOUR
AU  - Pavlović, Stefan
AU  - Marinković, Dalibor
AU  - Kostić, Milan
AU  - Janković-Častvan, Ivona
AU  - Mojović, Ljiljana
AU  - Stanković, Miroslav
AU  - Veljković, Vlada B.
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3423
AB  - The present paper is focused on the development of a new environment-friendly methanolysis catalyst completely
based on waste materials: lignite coal fly ash and chicken eggshells. A novel catalyst based on CaO
supported on a fly ash-based zeolitic material (CaO/FA-ZM) was obtained from a cancrinite-sodalite group
zeolite-like material (vishnevite type) and active CaO by alkali activation in a new miniature autoclave reactor
system and hydration-dehydration. Agitation by rotation of the entire reaction mixture led to a more homogeneous
zeolitic product and saved both time and energy. The obtained catalyst structure corresponds to gismondine
and the crystallographic modification of calcium silicate (α’-dicalcium silicate) with deposited CaO.
The characteristics of the synthesized catalyst were determined using ED-XRF, XRD, FT-IR, SEM, Hg-porosimetry,
N2-physisorption, LDPSA, and Hammett indicators. The CaO/FA-ZM catalyst exhibited a high activity
(97.8% of FAME for only 30 min) and stability (a negligible drop in activity in five consecutive cycles) in the
methanolysis reaction under the optimal reaction conditions (temperature of 60 °C, methanol/oil molar ratio of
6:1, and catalyst concentration of 6 wt%). A kinetic study was performed using two different mechanisms: the
irreversible pseudo-first-order reaction mechanism in two regimes (heterogeneous and homogeneous) and the
changing mechanism combined with the triacylglycerol mass transfer limitation. Both models showed a satisfactory
agreement between the experimental and predicted values of conversion degree (R2 > 0.93), confirming
their validity for the CaO-based heterogeneously catalyzed methanolysis. The values of the activation
energy calculated for both mechanisms were 67.17 and 58.03 kJ mol−1, respectively.
PB  - Elsevier
T2  - Fuel
T1  - A CaO/zeolite-based catalyst obtained from waste chicken eggshell and coal fly ash for biodiesel production
VL  - 267
SP  - 117171
DO  - 10.1016/j.fuel.2020.117171
ER  - 

@article{
author = "Pavlović, Stefan and Marinković, Dalibor and Kostić, Milan and Janković-Častvan, Ivona and Mojović, Ljiljana and Stanković, Miroslav and Veljković, Vlada B.",
year = "2020",
abstract = "The present paper is focused on the development of a new environment-friendly methanolysis catalyst completely
based on waste materials: lignite coal fly ash and chicken eggshells. A novel catalyst based on CaO
supported on a fly ash-based zeolitic material (CaO/FA-ZM) was obtained from a cancrinite-sodalite group
zeolite-like material (vishnevite type) and active CaO by alkali activation in a new miniature autoclave reactor
system and hydration-dehydration. Agitation by rotation of the entire reaction mixture led to a more homogeneous
zeolitic product and saved both time and energy. The obtained catalyst structure corresponds to gismondine
and the crystallographic modification of calcium silicate (α’-dicalcium silicate) with deposited CaO.
The characteristics of the synthesized catalyst were determined using ED-XRF, XRD, FT-IR, SEM, Hg-porosimetry,
N2-physisorption, LDPSA, and Hammett indicators. The CaO/FA-ZM catalyst exhibited a high activity
(97.8% of FAME for only 30 min) and stability (a negligible drop in activity in five consecutive cycles) in the
methanolysis reaction under the optimal reaction conditions (temperature of 60 °C, methanol/oil molar ratio of
6:1, and catalyst concentration of 6 wt%). A kinetic study was performed using two different mechanisms: the
irreversible pseudo-first-order reaction mechanism in two regimes (heterogeneous and homogeneous) and the
changing mechanism combined with the triacylglycerol mass transfer limitation. Both models showed a satisfactory
agreement between the experimental and predicted values of conversion degree (R2 > 0.93), confirming
their validity for the CaO-based heterogeneously catalyzed methanolysis. The values of the activation
energy calculated for both mechanisms were 67.17 and 58.03 kJ mol−1, respectively.",
publisher = "Elsevier",
journal = "Fuel",
title = "A CaO/zeolite-based catalyst obtained from waste chicken eggshell and coal fly ash for biodiesel production",
volume = "267",
pages = "117171",
doi = "10.1016/j.fuel.2020.117171"
}

Pavlović, S., Marinković, D., Kostić, M., Janković-Častvan, I., Mojović, L., Stanković, M.,& Veljković, V. B.. (2020). A CaO/zeolite-based catalyst obtained from waste chicken eggshell and coal fly ash for biodiesel production. in Fuel
Elsevier., 267, 117171.
https://doi.org/10.1016/j.fuel.2020.117171

Pavlović S, Marinković D, Kostić M, Janković-Častvan I, Mojović L, Stanković M, Veljković VB. A CaO/zeolite-based catalyst obtained from waste chicken eggshell and coal fly ash for biodiesel production. in Fuel. 2020;267:117171.
doi:10.1016/j.fuel.2020.117171 .

Pavlović, Stefan, Marinković, Dalibor, Kostić, Milan, Janković-Častvan, Ivona, Mojović, Ljiljana, Stanković, Miroslav, Veljković, Vlada B., "A CaO/zeolite-based catalyst obtained from waste chicken eggshell and coal fly ash for biodiesel production" in Fuel, 267 (2020):117171,
https://doi.org/10.1016/j.fuel.2020.117171 . .

TY  - JOUR
AU  - Pajnik, Jelena
AU  - Radetić, Maja
AU  - Stojanovic, Dusica B.
AU  - Janković-Častvan, Ivona
AU  - Tadić, Vanja
AU  - Stanković, Miroslav
AU  - Jovanović, Dušan M.
AU  - Žižović, Irena
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4276
AB  - This study discusses the possibility of supercritical solvent impregnation of polypropylene and polyamide fabrics as well as cellulose acetate in the form of beads and films with pyrethrum extract in order to fabricate functionalized materials with repellent properties. Impregnation experiments were performed at temperature of 40 degrees C and pressures of 10 and 20 MPa in supercritical carbon dioxide. The time of impregnation was varied from 0.5 to 18 h. Loadings of pyrethrum extract into polypropylene fabrics and cellulose acetate films higher than 30% were attainable at 10 MPa. In the case of polyamide fabrics and cellulose acetate beads, the pressure of 20 MPa was needed for obtaining the loadings higher than 11%. Pyrethrum extract release study revealed different capabilities of the tested materials for the repellent release, implying a variety of their possible applications. The impregnated solids were characterized by SEM, DSC, FTIR, Mercury intrusion porosimetry analyses and HPLC analyses.
PB  - Elsevier
T2  - Journal of Supercritical Fluids
T1  - Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide
VL  - 136
SP  - 70
EP  - 81
DO  - 10.1016/j.supflu.2018.02.014
ER  - 

@article{
author = "Pajnik, Jelena and Radetić, Maja and Stojanovic, Dusica B. and Janković-Častvan, Ivona and Tadić, Vanja and Stanković, Miroslav and Jovanović, Dušan M. and Žižović, Irena",
year = "2018",
abstract = "This study discusses the possibility of supercritical solvent impregnation of polypropylene and polyamide fabrics as well as cellulose acetate in the form of beads and films with pyrethrum extract in order to fabricate functionalized materials with repellent properties. Impregnation experiments were performed at temperature of 40 degrees C and pressures of 10 and 20 MPa in supercritical carbon dioxide. The time of impregnation was varied from 0.5 to 18 h. Loadings of pyrethrum extract into polypropylene fabrics and cellulose acetate films higher than 30% were attainable at 10 MPa. In the case of polyamide fabrics and cellulose acetate beads, the pressure of 20 MPa was needed for obtaining the loadings higher than 11%. Pyrethrum extract release study revealed different capabilities of the tested materials for the repellent release, implying a variety of their possible applications. The impregnated solids were characterized by SEM, DSC, FTIR, Mercury intrusion porosimetry analyses and HPLC analyses.",
publisher = "Elsevier",
journal = "Journal of Supercritical Fluids",
title = "Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide",
volume = "136",
pages = "70-81",
doi = "10.1016/j.supflu.2018.02.014"
}

Pajnik, J., Radetić, M., Stojanovic, D. B., Janković-Častvan, I., Tadić, V., Stanković, M., Jovanović, D. M.,& Žižović, I.. (2018). Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide. in Journal of Supercritical Fluids
Elsevier., 136, 70-81.
https://doi.org/10.1016/j.supflu.2018.02.014

Pajnik J, Radetić M, Stojanovic DB, Janković-Častvan I, Tadić V, Stanković M, Jovanović DM, Žižović I. Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide. in Journal of Supercritical Fluids. 2018;136:70-81.
doi:10.1016/j.supflu.2018.02.014 .

Pajnik, Jelena, Radetić, Maja, Stojanovic, Dusica B., Janković-Častvan, Ivona, Tadić, Vanja, Stanković, Miroslav, Jovanović, Dušan M., Žižović, Irena, "Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide" in Journal of Supercritical Fluids, 136 (2018):70-81,
https://doi.org/10.1016/j.supflu.2018.02.014 . .

TY  - JOUR
AU  - Pajnik, Jelena
AU  - Radetić, Maja
AU  - Stojanovic, Dusica B.
AU  - Janković-Častvan, Ivona
AU  - Tadić, Vanja
AU  - Stanković, Miroslav
AU  - Jovanović, Dušan M.
AU  - Žižović, Irena
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2298
AB  - This study discusses the possibility of supercritical solvent impregnation of polypropylene and polyamide fabrics as well as cellulose acetate in the form of beads and films with pyrethrum extract in order to fabricate functionalized materials with repellent properties. Impregnation experiments were performed at temperature of 40 degrees C and pressures of 10 and 20 MPa in supercritical carbon dioxide. The time of impregnation was varied from 0.5 to 18 h. Loadings of pyrethrum extract into polypropylene fabrics and cellulose acetate films higher than 30% were attainable at 10 MPa. In the case of polyamide fabrics and cellulose acetate beads, the pressure of 20 MPa was needed for obtaining the loadings higher than 11%. Pyrethrum extract release study revealed different capabilities of the tested materials for the repellent release, implying a variety of their possible applications. The impregnated solids were characterized by SEM, DSC, FTIR, Mercury intrusion porosimetry analyses and HPLC analyses.
PB  - Elsevier
T2  - Journal of Supercritical Fluids
T1  - Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide
VL  - 136
SP  - 70
EP  - 81
DO  - 10.1016/j.supflu.2018.02.014
ER  - 

@article{
author = "Pajnik, Jelena and Radetić, Maja and Stojanovic, Dusica B. and Janković-Častvan, Ivona and Tadić, Vanja and Stanković, Miroslav and Jovanović, Dušan M. and Žižović, Irena",
year = "2018",
abstract = "This study discusses the possibility of supercritical solvent impregnation of polypropylene and polyamide fabrics as well as cellulose acetate in the form of beads and films with pyrethrum extract in order to fabricate functionalized materials with repellent properties. Impregnation experiments were performed at temperature of 40 degrees C and pressures of 10 and 20 MPa in supercritical carbon dioxide. The time of impregnation was varied from 0.5 to 18 h. Loadings of pyrethrum extract into polypropylene fabrics and cellulose acetate films higher than 30% were attainable at 10 MPa. In the case of polyamide fabrics and cellulose acetate beads, the pressure of 20 MPa was needed for obtaining the loadings higher than 11%. Pyrethrum extract release study revealed different capabilities of the tested materials for the repellent release, implying a variety of their possible applications. The impregnated solids were characterized by SEM, DSC, FTIR, Mercury intrusion porosimetry analyses and HPLC analyses.",
publisher = "Elsevier",
journal = "Journal of Supercritical Fluids",
title = "Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide",
volume = "136",
pages = "70-81",
doi = "10.1016/j.supflu.2018.02.014"
}

Pajnik, J., Radetić, M., Stojanovic, D. B., Janković-Častvan, I., Tadić, V., Stanković, M., Jovanović, D. M.,& Žižović, I.. (2018). Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide. in Journal of Supercritical Fluids
Elsevier., 136, 70-81.
https://doi.org/10.1016/j.supflu.2018.02.014

Pajnik J, Radetić M, Stojanovic DB, Janković-Častvan I, Tadić V, Stanković M, Jovanović DM, Žižović I. Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide. in Journal of Supercritical Fluids. 2018;136:70-81.
doi:10.1016/j.supflu.2018.02.014 .

Pajnik, Jelena, Radetić, Maja, Stojanovic, Dusica B., Janković-Častvan, Ivona, Tadić, Vanja, Stanković, Miroslav, Jovanović, Dušan M., Žižović, Irena, "Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide" in Journal of Supercritical Fluids, 136 (2018):70-81,
https://doi.org/10.1016/j.supflu.2018.02.014 . .

TY  - JOUR
AU  - Marković, Smilja B.
AU  - Stankovic, Ana
AU  - Dostanić, Jasmina
AU  - Veselinović, Ljiljana
AU  - Mančić, Lidija
AU  - Skapin, Sreco Davor
AU  - Drazic, Goran
AU  - Janković-Častvan, Ivona
AU  - Uskoković, Dragan P.
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2169
AB  - Mechanical milling of commercial ZnO and SnO2 was used to produce a ZnO/SnO2 composite with a high density of surface defects; in particular, zinc interstitials (Zni) and oxygen vacancies (VO). To determine the impact of surface defects on photocatalytic activity, the relative concentration ratio of bulk defects to surface defects was modified by annealing at 400 and 700 degrees C. The possible application of the ZnO/SnO2 composite as a natural sunlight and UV- light driven photocatalyst was revealed via de-colorization of methylene blue. In both cases the ZnO/SnO2 composite exhibited enhanced photocatalytic activity as compared to the pristine ZnO. In order to investigate the origin of the enhancement, the pristine metal oxides and composites were characterized using a variety of techniques, including X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), laser diffraction particle size analysis, Brunauer-Emmett-Teller, UV-Vis diffuse reflectance and photoluminescence spectroscopy. High-resolution transmission electron microscopy (HRTEM) and elemental mapping analyses were used to reveal the presence of SnO2 nanocrystallites on the surface of larger ZnO particles. The enhanced photocatalytic activity of the composite can be attributed to the synergetic effect of the surface defects and the ZnO/SnO2 heterojunction particles, which facilitated charge separation, thereby hindering the recombination of photogenerated carriers. This study draws attention to mechanical activation as an inexpensive and environmentally friendly technique for the large-scale production of the composite with an enhanced photocatalytic activity under illumination of either UV or sunlight.
PB  - The Royal Society of Chemistry
T2  - RSC Advances
T1  - Simultaneous enhancement of natural sunlightand artificial UV-driven photocatalytic activity of a mechanically activated ZnO/SnO2 composite
VL  - 7
IS  - 68
SP  - 42725
EP  - 42737
DO  - 10.1039/c7ra06895f
ER  - 

@article{
author = "Marković, Smilja B. and Stankovic, Ana and Dostanić, Jasmina and Veselinović, Ljiljana and Mančić, Lidija and Skapin, Sreco Davor and Drazic, Goran and Janković-Častvan, Ivona and Uskoković, Dragan P.",
year = "2017",
abstract = "Mechanical milling of commercial ZnO and SnO2 was used to produce a ZnO/SnO2 composite with a high density of surface defects; in particular, zinc interstitials (Zni) and oxygen vacancies (VO). To determine the impact of surface defects on photocatalytic activity, the relative concentration ratio of bulk defects to surface defects was modified by annealing at 400 and 700 degrees C. The possible application of the ZnO/SnO2 composite as a natural sunlight and UV- light driven photocatalyst was revealed via de-colorization of methylene blue. In both cases the ZnO/SnO2 composite exhibited enhanced photocatalytic activity as compared to the pristine ZnO. In order to investigate the origin of the enhancement, the pristine metal oxides and composites were characterized using a variety of techniques, including X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), laser diffraction particle size analysis, Brunauer-Emmett-Teller, UV-Vis diffuse reflectance and photoluminescence spectroscopy. High-resolution transmission electron microscopy (HRTEM) and elemental mapping analyses were used to reveal the presence of SnO2 nanocrystallites on the surface of larger ZnO particles. The enhanced photocatalytic activity of the composite can be attributed to the synergetic effect of the surface defects and the ZnO/SnO2 heterojunction particles, which facilitated charge separation, thereby hindering the recombination of photogenerated carriers. This study draws attention to mechanical activation as an inexpensive and environmentally friendly technique for the large-scale production of the composite with an enhanced photocatalytic activity under illumination of either UV or sunlight.",
publisher = "The Royal Society of Chemistry",
journal = "RSC Advances",
title = "Simultaneous enhancement of natural sunlightand artificial UV-driven photocatalytic activity of a mechanically activated ZnO/SnO2 composite",
volume = "7",
number = "68",
pages = "42725-42737",
doi = "10.1039/c7ra06895f"
}

Marković, S. B., Stankovic, A., Dostanić, J., Veselinović, L., Mančić, L., Skapin, S. D., Drazic, G., Janković-Častvan, I.,& Uskoković, D. P.. (2017). Simultaneous enhancement of natural sunlightand artificial UV-driven photocatalytic activity of a mechanically activated ZnO/SnO2 composite. in RSC Advances
The Royal Society of Chemistry., 7(68), 42725-42737.
https://doi.org/10.1039/c7ra06895f

Marković SB, Stankovic A, Dostanić J, Veselinović L, Mančić L, Skapin SD, Drazic G, Janković-Častvan I, Uskoković DP. Simultaneous enhancement of natural sunlightand artificial UV-driven photocatalytic activity of a mechanically activated ZnO/SnO2 composite. in RSC Advances. 2017;7(68):42725-42737.
doi:10.1039/c7ra06895f .

Marković, Smilja B., Stankovic, Ana, Dostanić, Jasmina, Veselinović, Ljiljana, Mančić, Lidija, Skapin, Sreco Davor, Drazic, Goran, Janković-Častvan, Ivona, Uskoković, Dragan P., "Simultaneous enhancement of natural sunlightand artificial UV-driven photocatalytic activity of a mechanically activated ZnO/SnO2 composite" in RSC Advances, 7, no. 68 (2017):42725-42737,
https://doi.org/10.1039/c7ra06895f . .

TY  - JOUR
AU  - Juma, Habish Amal
AU  - Lazarević, Slavica
AU  - Janković-Častvan, Ivona
AU  - Potkonjak, Branislav
AU  - Janaćković, Đorđe
AU  - Petrović, Rada
PY  - 2015
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3874
AB  - In this study, the sorption of cadmium ions onto sepiolite modified with hydrated iron(III) oxide, Fe(III)-sepiolite, has been investigated in natural seawater, artificial seawater, aqueous solution of NaCl of the same ionic strength as the seawater and distilled water. The sorption experiments were performed as a function of the initial solution pH value, initial metal concentration, and equilibration time, using the batch method. The equilibrium sorption data were analyzed by the Langmuir, Freundlich and Sips isotherm models and the kinetics of sorption was analyzed using the pseudo-first-order and the pseudosecond-order kinetic models. The maximum sorption capacity and the strength of the sorbate-sorbent bonds at initial pH 7 were found to decrease in the following order: distilled water > NaCl solution > artificial seawater > natural seawater. The values of parameter nS in the Sips model, which fitted the equilibrium sorption results best, showed that heterogeneity of the sorbent surface was the highest in distilled water and the lowest in natural seawater. The sorption kinetic data fitted well with the pseudo-second-order kinetic model, which suggests that the rate-limiting step in Cd2+ sorption onto Fe(III)-sepiolite could be chemisorption. The low desorption percentage in both distilled water and 0.001 M HNO3 indicated that sorption occurred mainly by chemisorption mechanisms.
AB  - U ovom radu je proučavana sorpcija jona kadmijuma iz prirodne morske vode, laboratorijski pripremljene morske vode, vodenog rastvora NaCl iste jonske jačine kao morska voda i destilovane vode, na sepiolitu modifikovanom hidratisanim gvožđe(III)-oksidom. Eksperimenti su izvedeni u šaržnim uslovima, pri različitim početnim pH vrednostima, početnim koncentracijama jona kadmijuma i vremenima uravnotežavanja. Rezultati sorpcije u ravnotežnim uslovima su analizirani primenom modela Langmira, Frojndliha i Sipsa, a kinetika sorpcije je analizirana kinetičkim modelima pseudo-prvog i pseudo-drugog reda. Utvrđeno je da maksimalni adsorpcioni kapacitet i jačina veza sorbat-sorbent pri početnoj pH 7 opadaju u nizu: destilovana voda > NaCl rastvor > laboratorijski pripremljena morska voda > prirodna morska voda. Vrednosti parametra ns u modelu Sipsa, koji najbolje opisuje eksperimentalne rezultate, pokazuju da je heterogenost površine sorbenta najveća u destilovanoj vodi i najmanja u prirodnoj morskoj vodi. Rezultati ispitivanja kinetike sorpcije se bolje fituju modelom pseudo-drugog reda, što sugeriše da stupanj koji određuje brzinu sorpcije može biti hemisorpcija. Mali stepen desorpcije i u destilovanoj vodi i u 0.001 M HNO3 je potvrdio da se joni kadmijuma vezuju za modifikovani sepiolit uglavnom hemisorpcijom.
PB  - Belgrade : Association of the Chemical Engineers of Serbia
T2  - Chemical Industry and Chemical Engineering Quarterly
T1  - The effect of salinity on the sorption of cadmium ions from aqueous medium on Fe(III)-sepiolite
T1  - Uticaj saliniteta vode na sorpciju jona kadmijuma na Fe(III)-sepiolitu
VL  - 21
IS  - 2
SP  - 295
EP  - 303
DO  - 10.2298/CICEQ140130028H
ER  - 

@article{
author = "Juma, Habish Amal and Lazarević, Slavica and Janković-Častvan, Ivona and Potkonjak, Branislav and Janaćković, Đorđe and Petrović, Rada",
year = "2015",
abstract = "In this study, the sorption of cadmium ions onto sepiolite modified with hydrated iron(III) oxide, Fe(III)-sepiolite, has been investigated in natural seawater, artificial seawater, aqueous solution of NaCl of the same ionic strength as the seawater and distilled water. The sorption experiments were performed as a function of the initial solution pH value, initial metal concentration, and equilibration time, using the batch method. The equilibrium sorption data were analyzed by the Langmuir, Freundlich and Sips isotherm models and the kinetics of sorption was analyzed using the pseudo-first-order and the pseudosecond-order kinetic models. The maximum sorption capacity and the strength of the sorbate-sorbent bonds at initial pH 7 were found to decrease in the following order: distilled water > NaCl solution > artificial seawater > natural seawater. The values of parameter nS in the Sips model, which fitted the equilibrium sorption results best, showed that heterogeneity of the sorbent surface was the highest in distilled water and the lowest in natural seawater. The sorption kinetic data fitted well with the pseudo-second-order kinetic model, which suggests that the rate-limiting step in Cd2+ sorption onto Fe(III)-sepiolite could be chemisorption. The low desorption percentage in both distilled water and 0.001 M HNO3 indicated that sorption occurred mainly by chemisorption mechanisms., U ovom radu je proučavana sorpcija jona kadmijuma iz prirodne morske vode, laboratorijski pripremljene morske vode, vodenog rastvora NaCl iste jonske jačine kao morska voda i destilovane vode, na sepiolitu modifikovanom hidratisanim gvožđe(III)-oksidom. Eksperimenti su izvedeni u šaržnim uslovima, pri različitim početnim pH vrednostima, početnim koncentracijama jona kadmijuma i vremenima uravnotežavanja. Rezultati sorpcije u ravnotežnim uslovima su analizirani primenom modela Langmira, Frojndliha i Sipsa, a kinetika sorpcije je analizirana kinetičkim modelima pseudo-prvog i pseudo-drugog reda. Utvrđeno je da maksimalni adsorpcioni kapacitet i jačina veza sorbat-sorbent pri početnoj pH 7 opadaju u nizu: destilovana voda > NaCl rastvor > laboratorijski pripremljena morska voda > prirodna morska voda. Vrednosti parametra ns u modelu Sipsa, koji najbolje opisuje eksperimentalne rezultate, pokazuju da je heterogenost površine sorbenta najveća u destilovanoj vodi i najmanja u prirodnoj morskoj vodi. Rezultati ispitivanja kinetike sorpcije se bolje fituju modelom pseudo-drugog reda, što sugeriše da stupanj koji određuje brzinu sorpcije može biti hemisorpcija. Mali stepen desorpcije i u destilovanoj vodi i u 0.001 M HNO3 je potvrdio da se joni kadmijuma vezuju za modifikovani sepiolit uglavnom hemisorpcijom.",
publisher = "Belgrade : Association of the Chemical Engineers of Serbia",
journal = "Chemical Industry and Chemical Engineering Quarterly",
title = "The effect of salinity on the sorption of cadmium ions from aqueous medium on Fe(III)-sepiolite, Uticaj saliniteta vode na sorpciju jona kadmijuma na Fe(III)-sepiolitu",
volume = "21",
number = "2",
pages = "295-303",
doi = "10.2298/CICEQ140130028H"
}

Juma, H. A., Lazarević, S., Janković-Častvan, I., Potkonjak, B., Janaćković, Đ.,& Petrović, R.. (2015). The effect of salinity on the sorption of cadmium ions from aqueous medium on Fe(III)-sepiolite. in Chemical Industry and Chemical Engineering Quarterly
Belgrade : Association of the Chemical Engineers of Serbia., 21(2), 295-303.
https://doi.org/10.2298/CICEQ140130028H

Juma HA, Lazarević S, Janković-Častvan I, Potkonjak B, Janaćković Đ, Petrović R. The effect of salinity on the sorption of cadmium ions from aqueous medium on Fe(III)-sepiolite. in Chemical Industry and Chemical Engineering Quarterly. 2015;21(2):295-303.
doi:10.2298/CICEQ140130028H .

Juma, Habish Amal, Lazarević, Slavica, Janković-Častvan, Ivona, Potkonjak, Branislav, Janaćković, Đorđe, Petrović, Rada, "The effect of salinity on the sorption of cadmium ions from aqueous medium on Fe(III)-sepiolite" in Chemical Industry and Chemical Engineering Quarterly, 21, no. 2 (2015):295-303,
https://doi.org/10.2298/CICEQ140130028H . .

TY  - JOUR
AU  - Lazarević, Slavica
AU  - Janković-Častvan, Ivona
AU  - Onjia, Antonije E.
AU  - Krstić, Jugoslav
AU  - Janaćković, Đorđe
AU  - Petrovic, Rada
PY  - 2011
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/768
AB  - Inverse gas chromatography at infinite and finite surface coverages was applied to evaluate the surface properties of an iron-modified sepiolite sorbent, Fe-sepiolite. The adsorptions of different nonpolar and polar probes were measured in the infinite-dilution regime, in the temperature range 483-513 K. For the organic probes used, the thermodynamic parameters (free energy, enthalpy, and entropy) of adsorption and the dispersive and specific components of the free energy of adsorption were determined and are discussed in terms of specific reactions that can occur on the adsorbent surface. Following the approach of Gutmann (The Donor Acceptor Approach to Molecular Interactions; Plenum Press: New York, 1978), acid/base surface characteristics were determined. The adsorption isotherms of n-hexane, benzene, chloroform, and tetrahydrofuran were used to estimate the specific surface areas, isosteric heats of adsorption, and adsorption energy distributions for the adsorption of organic molecules.
PB  - American Chemical Society (ACS)
T2  - Industrial and Engineering Chemistry Research
T1  - Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography
VL  - 50
IS  - 20
SP  - 11467
EP  - 11475
DO  - 10.1021/ie200595n
ER  - 

@article{
author = "Lazarević, Slavica and Janković-Častvan, Ivona and Onjia, Antonije E. and Krstić, Jugoslav and Janaćković, Đorđe and Petrovic, Rada",
year = "2011",
abstract = "Inverse gas chromatography at infinite and finite surface coverages was applied to evaluate the surface properties of an iron-modified sepiolite sorbent, Fe-sepiolite. The adsorptions of different nonpolar and polar probes were measured in the infinite-dilution regime, in the temperature range 483-513 K. For the organic probes used, the thermodynamic parameters (free energy, enthalpy, and entropy) of adsorption and the dispersive and specific components of the free energy of adsorption were determined and are discussed in terms of specific reactions that can occur on the adsorbent surface. Following the approach of Gutmann (The Donor Acceptor Approach to Molecular Interactions; Plenum Press: New York, 1978), acid/base surface characteristics were determined. The adsorption isotherms of n-hexane, benzene, chloroform, and tetrahydrofuran were used to estimate the specific surface areas, isosteric heats of adsorption, and adsorption energy distributions for the adsorption of organic molecules.",
publisher = "American Chemical Society (ACS)",
journal = "Industrial and Engineering Chemistry Research",
title = "Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography",
volume = "50",
number = "20",
pages = "11467-11475",
doi = "10.1021/ie200595n"
}

Lazarević, S., Janković-Častvan, I., Onjia, A. E., Krstić, J., Janaćković, Đ.,& Petrovic, R.. (2011). Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography. in Industrial and Engineering Chemistry Research
American Chemical Society (ACS)., 50(20), 11467-11475.
https://doi.org/10.1021/ie200595n

Lazarević S, Janković-Častvan I, Onjia AE, Krstić J, Janaćković Đ, Petrovic R. Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography. in Industrial and Engineering Chemistry Research. 2011;50(20):11467-11475.
doi:10.1021/ie200595n .

Lazarević, Slavica, Janković-Častvan, Ivona, Onjia, Antonije E., Krstić, Jugoslav, Janaćković, Đorđe, Petrovic, Rada, "Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography" in Industrial and Engineering Chemistry Research, 50, no. 20 (2011):11467-11475,
https://doi.org/10.1021/ie200595n . .

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  - 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 . .