TY  - JOUR
AU  - Mladenović Nikolić, Nataša
AU  - Kljajević, Ljiljana
AU  - Nenadović, Snežana S.
AU  - Potočnik, Jelena
AU  - Knežević, Sanja
AU  - Dolenec, Sabina
AU  - Trivunac, Katarina
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7502
AB  - The objective of this study was to demonstrate the potential utilization of fly ash (FA), wood ash (WA), and metakaolin (MK) in developing new alkali-activated materials (AAMs) for the removal of cadmium ions from waste water. The synthesis of AAMs involved the dissolution of solid precursors, FA, WA, and MK, by a liquid activator (Na2SiO3 and NaOH). In concentrated solutions of the activator, the formation of an aluminosilicate gel structure occurred. DRIFT spectroscopy of the AAMs indicated main vibration bands between 1036 cm−1 and 996 cm−1, corresponding to Si-O-Si/Si-O-Al bands. Shifting vibration bands were seen at 1028 cm−1 to 1021 cm−1, indicating that the Si-O-Si/Si-O-Al bond is elongating, and the bond angle is decreasing. Based on the X-ray diffraction results, alkali-activated samples consist of an amorphous phase and residual mineral phases. The characteristic “hump” of an amorphous phase in the range from 20 to 40° 2θ was observed in FA and in all AWAFA samples. By the XRD patterns of the AAMs obtained by the activation of a solid three-component system, a new crystalline phase, gehlenite, was identified. The efficiency of AAMs in removing cadmium ions from aqueous solutions was tested under various conditions. The highest values of adsorption capacity, 64.76 mg/g (AWAFA6), 67.02 mg/g (AWAFAMK6), and 72.84 mg/g mg/g (AWAMK6), were obtained for materials activated with a 6 M NaOH solution in the alkali activator. The Langmuir adsorption isotherm and pseudo-second kinetic order provided the best fit for all investigated AAMs.
PB  - MDPI
T2  - Gels
T1  - Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials
IS  - 5
SP  - 317
VL  - 10
DO  - 10.3390/gels10050317
ER  - 

@article{
author = "Mladenović Nikolić, Nataša and Kljajević, Ljiljana and Nenadović, Snežana S. and Potočnik, Jelena and Knežević, Sanja and Dolenec, Sabina and Trivunac, Katarina",
year = "2024",
abstract = "The objective of this study was to demonstrate the potential utilization of fly ash (FA), wood ash (WA), and metakaolin (MK) in developing new alkali-activated materials (AAMs) for the removal of cadmium ions from waste water. The synthesis of AAMs involved the dissolution of solid precursors, FA, WA, and MK, by a liquid activator (Na2SiO3 and NaOH). In concentrated solutions of the activator, the formation of an aluminosilicate gel structure occurred. DRIFT spectroscopy of the AAMs indicated main vibration bands between 1036 cm−1 and 996 cm−1, corresponding to Si-O-Si/Si-O-Al bands. Shifting vibration bands were seen at 1028 cm−1 to 1021 cm−1, indicating that the Si-O-Si/Si-O-Al bond is elongating, and the bond angle is decreasing. Based on the X-ray diffraction results, alkali-activated samples consist of an amorphous phase and residual mineral phases. The characteristic “hump” of an amorphous phase in the range from 20 to 40° 2θ was observed in FA and in all AWAFA samples. By the XRD patterns of the AAMs obtained by the activation of a solid three-component system, a new crystalline phase, gehlenite, was identified. The efficiency of AAMs in removing cadmium ions from aqueous solutions was tested under various conditions. The highest values of adsorption capacity, 64.76 mg/g (AWAFA6), 67.02 mg/g (AWAFAMK6), and 72.84 mg/g mg/g (AWAMK6), were obtained for materials activated with a 6 M NaOH solution in the alkali activator. The Langmuir adsorption isotherm and pseudo-second kinetic order provided the best fit for all investigated AAMs.",
publisher = "MDPI",
journal = "Gels",
title = "Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials",
number = "5",
pages = "317",
volume = "10",
doi = "10.3390/gels10050317"
}

Mladenović Nikolić, N., Kljajević, L., Nenadović, S. S., Potočnik, J., Knežević, S., Dolenec, S.,& Trivunac, K.. (2024). Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials. in Gels
MDPI., 10(5), 317.
https://doi.org/10.3390/gels10050317

Mladenović Nikolić N, Kljajević L, Nenadović SS, Potočnik J, Knežević S, Dolenec S, Trivunac K. Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials. in Gels. 2024;10(5):317.
doi:10.3390/gels10050317 .

Mladenović Nikolić, Nataša, Kljajević, Ljiljana, Nenadović, Snežana S., Potočnik, Jelena, Knežević, Sanja, Dolenec, Sabina, Trivunac, Katarina, "Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials" in Gels, 10, no. 5 (2024):317,
https://doi.org/10.3390/gels10050317 . .

TY  - JOUR
AU  - Ivanović, Marija
AU  - Knežević, Sanja
AU  - Radović, Ivona
AU  - Kljajević, Ljiljana
AU  - Mirković, Miljana
AU  - Nenadović, Miloš
AU  - Nenadović, Snežana
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6311
AB  - Geopolymers have excellent physical and mechanical properties, so they can be used as a substitute for ordinary polymers. Geopolymers are ceramic materials, which exhibit the property of brittleness, which can be a limitation in some structural applications. To overcome this shortcoming, a new group of materials (organic geopolymers) was developed. The aim of this work is the synthesis of organic (hybrid) geopolymers. A geopolymer based on metakaolin was synthesized as a reference sample, while polyvinyl alcohol was added as an organic phase for synthesizing a hybrid geopolymer. It was concluded that the systems follow the rule of behavior in liquid systems. The chemical composition of the samples was determined by X-ray fluorescence analysis (XRF). Structural and phase characterization of hybrid and reference materials were analyzed using X-ray diffraction (XRD)and Fourier-transform infrared spectroscopy (FTIR), which revealed new phases in the PVA-added samples. The results show that the content of added PVA in the reaction mixture affects the phase composition of the synthesized materials. To examine the possibility of adsorption of the samples, Ultraviolet-visible spectroscopy (UV/VIS) was used. The morphology was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM/EDS), where efflorescence was observed and identified. After characterizing the geopolymer with the addition of PVA, we obtained a material that was far more porous than the basic sample, and we can conclude that we have synthesized a material that shows good mechanical properties.
PB  - MDPI
T2  - Sustainability (Switzerland)
T1  - Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA
IS  - 5
SP  - 4441
VL  - 15
DO  - 10.3390/su15054441
ER  - 

@article{
author = "Ivanović, Marija and Knežević, Sanja and Radović, Ivona and Kljajević, Ljiljana and Mirković, Miljana and Nenadović, Miloš and Nenadović, Snežana",
year = "2023",
abstract = "Geopolymers have excellent physical and mechanical properties, so they can be used as a substitute for ordinary polymers. Geopolymers are ceramic materials, which exhibit the property of brittleness, which can be a limitation in some structural applications. To overcome this shortcoming, a new group of materials (organic geopolymers) was developed. The aim of this work is the synthesis of organic (hybrid) geopolymers. A geopolymer based on metakaolin was synthesized as a reference sample, while polyvinyl alcohol was added as an organic phase for synthesizing a hybrid geopolymer. It was concluded that the systems follow the rule of behavior in liquid systems. The chemical composition of the samples was determined by X-ray fluorescence analysis (XRF). Structural and phase characterization of hybrid and reference materials were analyzed using X-ray diffraction (XRD)and Fourier-transform infrared spectroscopy (FTIR), which revealed new phases in the PVA-added samples. The results show that the content of added PVA in the reaction mixture affects the phase composition of the synthesized materials. To examine the possibility of adsorption of the samples, Ultraviolet-visible spectroscopy (UV/VIS) was used. The morphology was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM/EDS), where efflorescence was observed and identified. After characterizing the geopolymer with the addition of PVA, we obtained a material that was far more porous than the basic sample, and we can conclude that we have synthesized a material that shows good mechanical properties.",
publisher = "MDPI",
journal = "Sustainability (Switzerland)",
title = "Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA",
number = "5",
pages = "4441",
volume = "15",
doi = "10.3390/su15054441"
}

Ivanović, M., Knežević, S., Radović, I., Kljajević, L., Mirković, M., Nenadović, M.,& Nenadović, S.. (2023). Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA. in Sustainability (Switzerland)
MDPI., 15(5), 4441.
https://doi.org/10.3390/su15054441

Ivanović M, Knežević S, Radović I, Kljajević L, Mirković M, Nenadović M, Nenadović S. Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA. in Sustainability (Switzerland). 2023;15(5):4441.
doi:10.3390/su15054441 .

Ivanović, Marija, Knežević, Sanja, Radović, Ivona, Kljajević, Ljiljana, Mirković, Miljana, Nenadović, Miloš, Nenadović, Snežana, "Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA" in Sustainability (Switzerland), 15, no. 5 (2023):4441,
https://doi.org/10.3390/su15054441 . .