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 . .

TY  - JOUR
AU  - Obradović, Nina
AU  - Feng, Lun
AU  - Filipović, Suzana
AU  - Mirković, Miljana
AU  - Kosanović, Darko
AU  - Rogan, Jelena
AU  - Fahrenholtz, William G.
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6610
AB  - Zirconium carbide ceramics were prepared by carbothermal reduction of ZrO2 and C that were mixed by high-energy ball milling. Powders were milled for times from 0 to 120 min in air. As milling time increased, the surface area of the powders increased, indicating significant particle size reduction. Milled powders were reacted at 1600 °C and then densified by spark plasma sintering at 2000 °C, which was sufficient to convert the starting powders to zirconium carbide. Unmilled powders did not reach full density. Milled powders reached full density, but ZrO2 impurities were found for specimens prepared from powders milled for 60 and 120 min. Microstructure analysis showed that grain size was less than 2 µm for ceramics produced from powder milled for 15 min. Based on densification onset temperature and impurity levels, a milling time of 15 min gives the best balance of particle size reduction to promote densification while minimizing impurity levels.
PB  - Elsevier Ltd
T2  - Journal of the European Ceramic Society
T1  - Effect of mechanical activation on carbothermal synthesis and densification of ZrC
DO  - 10.1016/j.jeurceramsoc.2023.08.007
ER  - 

@article{
author = "Obradović, Nina and Feng, Lun and Filipović, Suzana and Mirković, Miljana and Kosanović, Darko and Rogan, Jelena and Fahrenholtz, William G.",
year = "2023",
abstract = "Zirconium carbide ceramics were prepared by carbothermal reduction of ZrO2 and C that were mixed by high-energy ball milling. Powders were milled for times from 0 to 120 min in air. As milling time increased, the surface area of the powders increased, indicating significant particle size reduction. Milled powders were reacted at 1600 °C and then densified by spark plasma sintering at 2000 °C, which was sufficient to convert the starting powders to zirconium carbide. Unmilled powders did not reach full density. Milled powders reached full density, but ZrO2 impurities were found for specimens prepared from powders milled for 60 and 120 min. Microstructure analysis showed that grain size was less than 2 µm for ceramics produced from powder milled for 15 min. Based on densification onset temperature and impurity levels, a milling time of 15 min gives the best balance of particle size reduction to promote densification while minimizing impurity levels.",
publisher = "Elsevier Ltd",
journal = "Journal of the European Ceramic Society",
title = "Effect of mechanical activation on carbothermal synthesis and densification of ZrC",
doi = "10.1016/j.jeurceramsoc.2023.08.007"
}

Obradović, N., Feng, L., Filipović, S., Mirković, M., Kosanović, D., Rogan, J.,& Fahrenholtz, W. G.. (2023). Effect of mechanical activation on carbothermal synthesis and densification of ZrC. in Journal of the European Ceramic Society
Elsevier Ltd..
https://doi.org/10.1016/j.jeurceramsoc.2023.08.007

Obradović N, Feng L, Filipović S, Mirković M, Kosanović D, Rogan J, Fahrenholtz WG. Effect of mechanical activation on carbothermal synthesis and densification of ZrC. in Journal of the European Ceramic Society. 2023;.
doi:10.1016/j.jeurceramsoc.2023.08.007 .

Obradović, Nina, Feng, Lun, Filipović, Suzana, Mirković, Miljana, Kosanović, Darko, Rogan, Jelena, Fahrenholtz, William G., "Effect of mechanical activation on carbothermal synthesis and densification of ZrC" in Journal of the European Ceramic Society (2023),
https://doi.org/10.1016/j.jeurceramsoc.2023.08.007 . .

TY  - JOUR
AU  - Mladenović Nikolić, Nataša N.
AU  - Kandić, Aleksandar B.
AU  - Trivunac, Katarina V.
AU  - Mirković, Miljana M.
AU  - Vukanac, Ivana S.
AU  - Nenadović, Snežana S.
AU  - Kljajević, Ljiljana M.
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5245
AB  - The aim of the presented research was to investigate the application possibility of wood ash and metakaolin to obtain alkali-activated materials as relatively new materials in the building industry. Thus, in order to assess the adequate use of these waste materials, structural and radiological characteristics should be considered. Until now, the focus has been on ash from thermal power plants produced by burning coal, but a large part of households in our country have individual fireplaces in which wood is used as the basic raw material; thus, it is very interesting to measure the activity concentration of radionuclide in wood ash as well as the possibility of reusing that ash for other purposes. All materials were studied, in terms of physical and chemical characteristics, by methods such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of wood ash samples showed that it consists of calcite and larnite. FTIR spectroscopy revealed a polymeric Si–O–Al framework in alkali-activated materials and Si–O bonding bands corresponding to silicon dioxide. Determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the alkaline activation process led to the decrease in the activity concentration of radionuclides detected in the measured samples. External radiation hazard index (Hex) for wood ash was reduced by more than 50% after alkali activation. The results of activity concentration measurements in alkali-activated materials indicate potential for their safe application in building construction.
PB  - MDPI
T2  - Sustainability (Switzerland)
T1  - Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends
IS  - 20
SP  - 12960
VL  - 14
DO  - 10.3390/su142012960
ER  - 

@article{
author = "Mladenović Nikolić, Nataša N. and Kandić, Aleksandar B. and Trivunac, Katarina V. and Mirković, Miljana M. and Vukanac, Ivana S. and Nenadović, Snežana S. and Kljajević, Ljiljana M.",
year = "2022",
abstract = "The aim of the presented research was to investigate the application possibility of wood ash and metakaolin to obtain alkali-activated materials as relatively new materials in the building industry. Thus, in order to assess the adequate use of these waste materials, structural and radiological characteristics should be considered. Until now, the focus has been on ash from thermal power plants produced by burning coal, but a large part of households in our country have individual fireplaces in which wood is used as the basic raw material; thus, it is very interesting to measure the activity concentration of radionuclide in wood ash as well as the possibility of reusing that ash for other purposes. All materials were studied, in terms of physical and chemical characteristics, by methods such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of wood ash samples showed that it consists of calcite and larnite. FTIR spectroscopy revealed a polymeric Si–O–Al framework in alkali-activated materials and Si–O bonding bands corresponding to silicon dioxide. Determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the alkaline activation process led to the decrease in the activity concentration of radionuclides detected in the measured samples. External radiation hazard index (Hex) for wood ash was reduced by more than 50% after alkali activation. The results of activity concentration measurements in alkali-activated materials indicate potential for their safe application in building construction.",
publisher = "MDPI",
journal = "Sustainability (Switzerland)",
title = "Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends",
number = "20",
pages = "12960",
volume = "14",
doi = "10.3390/su142012960"
}

Mladenović Nikolić, N. N., Kandić, A. B., Trivunac, K. V., Mirković, M. M., Vukanac, I. S., Nenadović, S. S.,& Kljajević, L. M.. (2022). Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends. in Sustainability (Switzerland)
MDPI., 14(20), 12960.
https://doi.org/10.3390/su142012960

Mladenović Nikolić NN, Kandić AB, Trivunac KV, Mirković MM, Vukanac IS, Nenadović SS, Kljajević LM. Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends. in Sustainability (Switzerland). 2022;14(20):12960.
doi:10.3390/su142012960 .

Mladenović Nikolić, Nataša N., Kandić, Aleksandar B., Trivunac, Katarina V., Mirković, Miljana M., Vukanac, Ivana S., Nenadović, Snežana S., Kljajević, Ljiljana M., "Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends" in Sustainability (Switzerland), 14, no. 20 (2022):12960,
https://doi.org/10.3390/su142012960 . .

TY  - JOUR
AU  - Trivunac, Katarina
AU  - Kljajević, Ljiljana M.
AU  - Nenadović, Snežana S.
AU  - Gulicovski, Jelena
AU  - Mirković, Miljana M.
AU  - Babić, Biljana M.
AU  - Stevanović, Slavica
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3340
AB  - The microstructural characterization and adsorption properties of metakaolin (MK) and alkali-activated metakaolin, known as geopolymer materials (GP) were investigated. The structure and properties of the metakaolin and obtained geopolymer were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of adsorption efficiency, microstructure and mineral structure, the difference between geopolymer and metakaolin on the performance of immobilizing heavy metals have been discussed. The kinetics of adsorption can be represented by pseudo-second order equation. The results of lead ions adsorption experiments were best fitted by Freundlich adsorption isotherm for both investigated adsorbents. The highest removal efficiencies of alkali-activated material based on metakaolin was found 97.5% at pH 4 and metakaolin removal efficiencies was found 92% at pH 5.5.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Microstructural Characterization and Adsorption Properties of Alkali-Activated Materials Based on Metakaolin
EP  - 220
IS  - 2
SP  - 209
VL  - 48
DO  - 10.2298/SOS1602209T
ER  - 

@article{
author = "Trivunac, Katarina and Kljajević, Ljiljana M. and Nenadović, Snežana S. and Gulicovski, Jelena and Mirković, Miljana M. and Babić, Biljana M. and Stevanović, Slavica",
year = "2016",
abstract = "The microstructural characterization and adsorption properties of metakaolin (MK) and alkali-activated metakaolin, known as geopolymer materials (GP) were investigated. The structure and properties of the metakaolin and obtained geopolymer were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of adsorption efficiency, microstructure and mineral structure, the difference between geopolymer and metakaolin on the performance of immobilizing heavy metals have been discussed. The kinetics of adsorption can be represented by pseudo-second order equation. The results of lead ions adsorption experiments were best fitted by Freundlich adsorption isotherm for both investigated adsorbents. The highest removal efficiencies of alkali-activated material based on metakaolin was found 97.5% at pH 4 and metakaolin removal efficiencies was found 92% at pH 5.5.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Microstructural Characterization and Adsorption Properties of Alkali-Activated Materials Based on Metakaolin",
pages = "220-209",
number = "2",
volume = "48",
doi = "10.2298/SOS1602209T"
}

Trivunac, K., Kljajević, L. M., Nenadović, S. S., Gulicovski, J., Mirković, M. M., Babić, B. M.,& Stevanović, S.. (2016). Microstructural Characterization and Adsorption Properties of Alkali-Activated Materials Based on Metakaolin. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 48(2), 209-220.
https://doi.org/10.2298/SOS1602209T

Trivunac K, Kljajević LM, Nenadović SS, Gulicovski J, Mirković MM, Babić BM, Stevanović S. Microstructural Characterization and Adsorption Properties of Alkali-Activated Materials Based on Metakaolin. in Science of Sintering. 2016;48(2):209-220.
doi:10.2298/SOS1602209T .

Trivunac, Katarina, Kljajević, Ljiljana M., Nenadović, Snežana S., Gulicovski, Jelena, Mirković, Miljana M., Babić, Biljana M., Stevanović, Slavica, "Microstructural Characterization and Adsorption Properties of Alkali-Activated Materials Based on Metakaolin" in Science of Sintering, 48, no. 2 (2016):209-220,
https://doi.org/10.2298/SOS1602209T . .