TY  - JOUR
AU  - Nenadović, Miloš
AU  - Ivanović, Marija
AU  - Kisić, Danilo
AU  - Bundaleski, Nenad
AU  - Pavlović, Vera
AU  - Knežević, Sanja
AU  - Kljajević, Ljiljana
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12727
AB  - In the present paper, polymerization of alkali activated metakaolin (MK) and its structural changing, using 2M NaOH, 8M NaOH, and 16M NaOH solutions were followed by means of X-ray photoelectron spectroscopy (XPS), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy and Scanning electron microscopy (SEM). XPS analysis revealed that changing of NaOH concentration did not affect the types of formed bonds in the material. At the same time, the amount of sodium and aluminum increased with the NaOH molarity. The latter steps could be especially interesting because it may indicate the possibility of 'dosing' the amount of Al incorporated by changing the NaOH concentration in the solution. DRIFT analysis revealed that the absorption band for AlIV located at 800 cm-1 is shifted towards the smaller values. Changing the concentration of NaOH, the chemical content did not change, but the structural changes are observed. Raman spectroscopy detected that the most dominant peaks at ∼400 cm-1 and 519 cm-1 originate from Si-O-Al and Si-O-Si bending modes. With increasing the NaOH concentration, peaks at 1019-1060 cm-1 become more prominent as a result of polymerization. Both analyzes (DRIFT and Raman) confirmed the presence of quartz. SEM analysis showed that different structures are created by changing the concentration of NaOH.
AB  - У овом раду, праћена је полимеризација алкално активираног метакаолина (МК) и његове структурне промене, коришћењем 2М NaOH, 8М NaOH и 16М раствора NaOH. Промене су праћене рендгенском фотоелектронском спектроскопијом (XPS), дифузном рефлексијом инфрацрвене Фуријеове трансформације (DRIFT), Рамановом спектроскопијом и скенирајућом електронском микроскопијом (SEM). XPS анализа је показала да промена концентрације NaOH није утицала на типове формираних веза у материјалу. Истовремено, количина натријума и алуминијума се повећавала са моларношћу NaOH. Последњи кораци могу бити посебно интересантни јер могу указивати на могућност 'дозирања' количине Al инкорпорираног променом концентрације NaOH у раствору. DRIFT анализа је открила да је опсег апсорпције за AlIV који се налази на 800 cm-1 померен ка мањим вредностима. Променом концентрације NaOH, хемијски садржај се није мењао, али су уочене структурне промене. Раманова спектроскопија је открила да најдоминантнији пикови на 400 cm-1 и 519 cm-1 потичу из Si-О-Al и Si-О-Si начина савијања хемијских веза. Са повећањем концентрације NaOH, пикови на 1019-1060 cm-1 постају све израженији као резултат полимеризације. Обе анализе (DRIFT и Раман) потврдиле су присуство кварца. SEM анализа је показала да се променом концентрације NaOH стварају различите структуре.
T2  - Science of Sintering
T1  - Changes in the physicochemical properties of geopolymer gels as a function of NaOH concentration
VL  - 55
IS  - 4
SP  - 509
EP  - 519
DO  - 10.2298/SOS220624020N
ER  - 

@article{
author = "Nenadović, Miloš and Ivanović, Marija and Kisić, Danilo and Bundaleski, Nenad and Pavlović, Vera and Knežević, Sanja and Kljajević, Ljiljana",
year = "2024",
abstract = "In the present paper, polymerization of alkali activated metakaolin (MK) and its structural changing, using 2M NaOH, 8M NaOH, and 16M NaOH solutions were followed by means of X-ray photoelectron spectroscopy (XPS), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy and Scanning electron microscopy (SEM). XPS analysis revealed that changing of NaOH concentration did not affect the types of formed bonds in the material. At the same time, the amount of sodium and aluminum increased with the NaOH molarity. The latter steps could be especially interesting because it may indicate the possibility of 'dosing' the amount of Al incorporated by changing the NaOH concentration in the solution. DRIFT analysis revealed that the absorption band for AlIV located at 800 cm-1 is shifted towards the smaller values. Changing the concentration of NaOH, the chemical content did not change, but the structural changes are observed. Raman spectroscopy detected that the most dominant peaks at ∼400 cm-1 and 519 cm-1 originate from Si-O-Al and Si-O-Si bending modes. With increasing the NaOH concentration, peaks at 1019-1060 cm-1 become more prominent as a result of polymerization. Both analyzes (DRIFT and Raman) confirmed the presence of quartz. SEM analysis showed that different structures are created by changing the concentration of NaOH., У овом раду, праћена је полимеризација алкално активираног метакаолина (МК) и његове структурне промене, коришћењем 2М NaOH, 8М NaOH и 16М раствора NaOH. Промене су праћене рендгенском фотоелектронском спектроскопијом (XPS), дифузном рефлексијом инфрацрвене Фуријеове трансформације (DRIFT), Рамановом спектроскопијом и скенирајућом електронском микроскопијом (SEM). XPS анализа је показала да промена концентрације NaOH није утицала на типове формираних веза у материјалу. Истовремено, количина натријума и алуминијума се повећавала са моларношћу NaOH. Последњи кораци могу бити посебно интересантни јер могу указивати на могућност 'дозирања' количине Al инкорпорираног променом концентрације NaOH у раствору. DRIFT анализа је открила да је опсег апсорпције за AlIV који се налази на 800 cm-1 померен ка мањим вредностима. Променом концентрације NaOH, хемијски садржај се није мењао, али су уочене структурне промене. Раманова спектроскопија је открила да најдоминантнији пикови на 400 cm-1 и 519 cm-1 потичу из Si-О-Al и Si-О-Si начина савијања хемијских веза. Са повећањем концентрације NaOH, пикови на 1019-1060 cm-1 постају све израженији као резултат полимеризације. Обе анализе (DRIFT и Раман) потврдиле су присуство кварца. SEM анализа је показала да се променом концентрације NaOH стварају различите структуре.",
journal = "Science of Sintering",
title = "Changes in the physicochemical properties of geopolymer gels as a function of NaOH concentration",
volume = "55",
number = "4",
pages = "509-519",
doi = "10.2298/SOS220624020N"
}

Nenadović, M., Ivanović, M., Kisić, D., Bundaleski, N., Pavlović, V., Knežević, S.,& Kljajević, L.. (2024). Changes in the physicochemical properties of geopolymer gels as a function of NaOH concentration. in Science of Sintering, 55(4), 509-519.
https://doi.org/10.2298/SOS220624020N

Nenadović M, Ivanović M, Kisić D, Bundaleski N, Pavlović V, Knežević S, Kljajević L. Changes in the physicochemical properties of geopolymer gels as a function of NaOH concentration. in Science of Sintering. 2024;55(4):509-519.
doi:10.2298/SOS220624020N .

Nenadović, Miloš, Ivanović, Marija, Kisić, Danilo, Bundaleski, Nenad, Pavlović, Vera, Knežević, Sanja, Kljajević, Ljiljana, "Changes in the physicochemical properties of geopolymer gels as a function of NaOH concentration" in Science of Sintering, 55, no. 4 (2024):509-519,
https://doi.org/10.2298/SOS220624020N . .

TY  - JOUR
AU  - Ivanović, Marija M.
AU  - Knežević, Sanja
AU  - Mirković, Miljana M.
AU  - Kljajević, Ljiljana M.
AU  - Bučevac, Dušan
AU  - Pavlović, Vladimir B.
AU  - Nenadović, Miloš
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10741
AB  - It is well known that geopolymers are a new group of binder materials of alumosilicate origin. Geopolymers are made by the reaction of precursor aluminosilicate materials with alkaline activator solutions. The current research relates to a low-cost and eco-friendly procedure, suitable of being implemented in two easy steps. The first step is the production of a solid phase based on fly ash (Obrenovac, Serbia) and eggshell ash as waste materials rich in calcium. The second step is alkali activating the solid phase using an alkaline activator (a mixture of NaOH and Na2SiO3) and procedures in proper laboratory conditions. Four samples with different eggshell ash content were synthesized. The concentration of used NaOH was 12 mol dm−3. The structural properties of all investigated samples were analyzed by XRD (X-ray diffraction), DRIFT (diffuse reflectance infrared Fourier transform), SEM (scanning electron microscopy) and UV/Vis spectroscopy analysis. XRD determined the amorphous halo with the presence of quartz as the crystal phase in all of the investigated samples. These results were confirmed by DRIFT analysis. The morphology of the samples was determined by SEM analysis. UV/Vis showed that the material could be a potential adsorbent.
T2  - Sustainability
T1  - Structural Characterization of Geopolymers with the Addition of Eggshell Ash
VL  - 15
IS  - 6
SP  - 5419
DO  - 10.3390/su15065419
ER  - 

@article{
author = "Ivanović, Marija M. and Knežević, Sanja and Mirković, Miljana M. and Kljajević, Ljiljana M. and Bučevac, Dušan and Pavlović, Vladimir B. and Nenadović, Miloš",
year = "2023",
abstract = "It is well known that geopolymers are a new group of binder materials of alumosilicate origin. Geopolymers are made by the reaction of precursor aluminosilicate materials with alkaline activator solutions. The current research relates to a low-cost and eco-friendly procedure, suitable of being implemented in two easy steps. The first step is the production of a solid phase based on fly ash (Obrenovac, Serbia) and eggshell ash as waste materials rich in calcium. The second step is alkali activating the solid phase using an alkaline activator (a mixture of NaOH and Na2SiO3) and procedures in proper laboratory conditions. Four samples with different eggshell ash content were synthesized. The concentration of used NaOH was 12 mol dm−3. The structural properties of all investigated samples were analyzed by XRD (X-ray diffraction), DRIFT (diffuse reflectance infrared Fourier transform), SEM (scanning electron microscopy) and UV/Vis spectroscopy analysis. XRD determined the amorphous halo with the presence of quartz as the crystal phase in all of the investigated samples. These results were confirmed by DRIFT analysis. The morphology of the samples was determined by SEM analysis. UV/Vis showed that the material could be a potential adsorbent.",
journal = "Sustainability",
title = "Structural Characterization of Geopolymers with the Addition of Eggshell Ash",
volume = "15",
number = "6",
pages = "5419",
doi = "10.3390/su15065419"
}

Ivanović, M. M., Knežević, S., Mirković, M. M., Kljajević, L. M., Bučevac, D., Pavlović, V. B.,& Nenadović, M.. (2023). Structural Characterization of Geopolymers with the Addition of Eggshell Ash. in Sustainability, 15(6), 5419.
https://doi.org/10.3390/su15065419

Ivanović MM, Knežević S, Mirković MM, Kljajević LM, Bučevac D, Pavlović VB, Nenadović M. Structural Characterization of Geopolymers with the Addition of Eggshell Ash. in Sustainability. 2023;15(6):5419.
doi:10.3390/su15065419 .

Ivanović, Marija M., Knežević, Sanja, Mirković, Miljana M., Kljajević, Ljiljana M., Bučevac, Dušan, Pavlović, Vladimir B., Nenadović, Miloš, "Structural Characterization of Geopolymers with the Addition of Eggshell Ash" in Sustainability, 15, no. 6 (2023):5419,
https://doi.org/10.3390/su15065419 . .

TY  - JOUR
AU  - Ivanović, Marija M.
AU  - Knežević, Sanja
AU  - Radović, Ivona
AU  - Kljajević, Ljiljana M.
AU  - Mirković, Miljana M.
AU  - Nenadović, Miloš
AU  - Nenadović, Snežana S.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10742
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.
T2  - Sustainability
T1  - Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA
VL  - 15
IS  - 5
SP  - 4441
DO  - 10.3390/su15054441
ER  - 

@article{
author = "Ivanović, Marija M. and Knežević, Sanja and Radović, Ivona and Kljajević, Ljiljana M. and Mirković, Miljana M. and Nenadović, Miloš and Nenadović, Snežana S.",
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.",
journal = "Sustainability",
title = "Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA",
volume = "15",
number = "5",
pages = "4441",
doi = "10.3390/su15054441"
}

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

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

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

TY  - CONF
AU  - Perić, Marko
AU  - Vuković, George
AU  - Knežević, Sanja
AU  - Nikolić, Milan
AU  - Šuljagić, Marija
AU  - Anđelković, Ljubica
AU  - Nenadović, Snežana
AU  - Ivanović, Marija M.
AU  - Mirković, Miljana
AU  - Pavlović, Vladmir B.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11279
AB  - Radiation shielding is a crucial precautionary measure in decreasing the dose of exposure medical personnel experience. The physical dimensions of these shields, specifically thickness and shape, are dependent on the type of radiation, energy and specific radioactivity. Currently, the most common radiation shielding equipment is made of lead, tungsten or uranium. Although these heavy metals have favorable shielding properties against ionizing radiation, protective garments such as lead aprons are heavy to wear and can pose significant health risks. Taking this into account, the primary goal of this study is to understand the radiation shielding properties of lead-free polymer geopolymer-polyurethane based composites. The geopolymer was synthesized using an 80%-20% mixture of fly ash and a bio-polyol substrate which was subsequently homogenized using MDI44. As a result, 6 samples of the geopolymer-polyurethane based composites were fabricated of which 5 were 90%-10% compositions between the mixture and varying concentrations of BaSO4 and Bi2O3 respectively. The last sample consisted of the pure fly ash/bio-polyol mixture. XRF and ICP analysis was used to chemically characterize the fly ash. The composite structures were analyzed using XRD, while the microstructural morphology was investigated using SEM techniques. Utilizing an energy-dispersive x-ray spectrometer (EDS), elemental abundance and agglomerating behavior was analyzed for each composite variant. The X-ray attenuation measurements pointed out that the obtained composites have the potential for a design of lead-free protective clothing against X-ray shielding in medical applications.
PB  - Bucharest: SRMNIM
C3  - Abstracts E-Book, 10th Balkan Congress of Nuclear Medicine & 5th Romanian Congress of Nuclear Medicine, 15-18 March, 2023, Bucharest, Romania
T1  - Lead Free Polymer Composites for Radiation Shielding
SP  - 17
EP  - 17
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11279
ER  - 

@conference{
author = "Perić, Marko and Vuković, George and Knežević, Sanja and Nikolić, Milan and Šuljagić, Marija and Anđelković, Ljubica and Nenadović, Snežana and Ivanović, Marija M. and Mirković, Miljana and Pavlović, Vladmir B.",
year = "2023",
abstract = "Radiation shielding is a crucial precautionary measure in decreasing the dose of exposure medical personnel experience. The physical dimensions of these shields, specifically thickness and shape, are dependent on the type of radiation, energy and specific radioactivity. Currently, the most common radiation shielding equipment is made of lead, tungsten or uranium. Although these heavy metals have favorable shielding properties against ionizing radiation, protective garments such as lead aprons are heavy to wear and can pose significant health risks. Taking this into account, the primary goal of this study is to understand the radiation shielding properties of lead-free polymer geopolymer-polyurethane based composites. The geopolymer was synthesized using an 80%-20% mixture of fly ash and a bio-polyol substrate which was subsequently homogenized using MDI44. As a result, 6 samples of the geopolymer-polyurethane based composites were fabricated of which 5 were 90%-10% compositions between the mixture and varying concentrations of BaSO4 and Bi2O3 respectively. The last sample consisted of the pure fly ash/bio-polyol mixture. XRF and ICP analysis was used to chemically characterize the fly ash. The composite structures were analyzed using XRD, while the microstructural morphology was investigated using SEM techniques. Utilizing an energy-dispersive x-ray spectrometer (EDS), elemental abundance and agglomerating behavior was analyzed for each composite variant. The X-ray attenuation measurements pointed out that the obtained composites have the potential for a design of lead-free protective clothing against X-ray shielding in medical applications.",
publisher = "Bucharest: SRMNIM",
journal = "Abstracts E-Book, 10th Balkan Congress of Nuclear Medicine & 5th Romanian Congress of Nuclear Medicine, 15-18 March, 2023, Bucharest, Romania",
title = "Lead Free Polymer Composites for Radiation Shielding",
pages = "17-17",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11279"
}

Perić, M., Vuković, G., Knežević, S., Nikolić, M., Šuljagić, M., Anđelković, L., Nenadović, S., Ivanović, M. M., Mirković, M.,& Pavlović, V. B.. (2023). Lead Free Polymer Composites for Radiation Shielding. in Abstracts E-Book, 10th Balkan Congress of Nuclear Medicine & 5th Romanian Congress of Nuclear Medicine, 15-18 March, 2023, Bucharest, Romania
Bucharest: SRMNIM., 17-17.
https://hdl.handle.net/21.15107/rcub_vinar_11279

Perić M, Vuković G, Knežević S, Nikolić M, Šuljagić M, Anđelković L, Nenadović S, Ivanović MM, Mirković M, Pavlović VB. Lead Free Polymer Composites for Radiation Shielding. in Abstracts E-Book, 10th Balkan Congress of Nuclear Medicine & 5th Romanian Congress of Nuclear Medicine, 15-18 March, 2023, Bucharest, Romania. 2023;:17-17.
https://hdl.handle.net/21.15107/rcub_vinar_11279 .

Perić, Marko, Vuković, George, Knežević, Sanja, Nikolić, Milan, Šuljagić, Marija, Anđelković, Ljubica, Nenadović, Snežana, Ivanović, Marija M., Mirković, Miljana, Pavlović, Vladmir B., "Lead Free Polymer Composites for Radiation Shielding" in Abstracts E-Book, 10th Balkan Congress of Nuclear Medicine & 5th Romanian Congress of Nuclear Medicine, 15-18 March, 2023, Bucharest, Romania (2023):17-17,
https://hdl.handle.net/21.15107/rcub_vinar_11279 .

TY  - CONF
AU  - Mladenović Nikolić, Nataša
AU  - Knežević, Sanja
AU  - Ivanović, Marija M.
AU  - Mirković, Miljana
AU  - Maletić, M.
AU  - Kljajević, Ljiljana
AU  - Trivunac, K.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11754
AB  - The aim of this paper is to show the possibility of using waste materials, blends of (wood ash, fly ash, from thermal power plant, and metakaolin) for the production of alkali activated materials that can be used to purify wastewater from different kinds of pollutants such as heavy metals. Heavy metals are toxic, especially cadmium, so they must be removed from wastewater to prevent or minimize contact with the environment and humans. The synthesis of the alkali activated materials was performed by mixing solid precursors with a liquid alkali activator. Two- and three-component systems of wood ash, fly ash and metakaolin (wood ash/fly ash, wood ash/metakaolin, fly ash/metakaolin and wood ash/fly ash/metakaolin) were used as precursor materials. The alkali activator solution was a mixture of sodium silicate solution and sodium hydroxide solution of concentrations (6M and 12M). The characterization of alkali activated materials was studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of investigated samples showed a characteristic halo between 18 and 35º 2 with a dominant crystal phase of quartz. FTIR spectroscopy showed that the main vibration band of all investigated samples appeared between 1037-996 cm-1, and corresponds to Si-O-Si/Si-O-Al bands. SEM/EDS analysis was used to determine the microstructure of the samples. The adsorption efficiency of the investigated alkali activated materials for removing cadmium ions from aqueous solution was tested under different conditions: initial concentration of cadmium ions in the range of 20-100 mg/l, pH values from 3 to 7 and mass of adsorbents from 0.02-0.05 g.
PB  - Society of Chemists and Technologists of Macedonia
C3  - 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
T1  - Structural Characteristics and Adsorption Properties of Alkali Activated Blends Ashes/Metakaolin
SP  - 29
EP  - 29
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11754
ER  - 

@conference{
author = "Mladenović Nikolić, Nataša and Knežević, Sanja and Ivanović, Marija M. and Mirković, Miljana and Maletić, M. and Kljajević, Ljiljana and Trivunac, K.",
year = "2023",
abstract = "The aim of this paper is to show the possibility of using waste materials, blends of (wood ash, fly ash, from thermal power plant, and metakaolin) for the production of alkali activated materials that can be used to purify wastewater from different kinds of pollutants such as heavy metals. Heavy metals are toxic, especially cadmium, so they must be removed from wastewater to prevent or minimize contact with the environment and humans. The synthesis of the alkali activated materials was performed by mixing solid precursors with a liquid alkali activator. Two- and three-component systems of wood ash, fly ash and metakaolin (wood ash/fly ash, wood ash/metakaolin, fly ash/metakaolin and wood ash/fly ash/metakaolin) were used as precursor materials. The alkali activator solution was a mixture of sodium silicate solution and sodium hydroxide solution of concentrations (6M and 12M). The characterization of alkali activated materials was studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of investigated samples showed a characteristic halo between 18 and 35º 2 with a dominant crystal phase of quartz. FTIR spectroscopy showed that the main vibration band of all investigated samples appeared between 1037-996 cm-1, and corresponds to Si-O-Si/Si-O-Al bands. SEM/EDS analysis was used to determine the microstructure of the samples. The adsorption efficiency of the investigated alkali activated materials for removing cadmium ions from aqueous solution was tested under different conditions: initial concentration of cadmium ions in the range of 20-100 mg/l, pH values from 3 to 7 and mass of adsorbents from 0.02-0.05 g.",
publisher = "Society of Chemists and Technologists of Macedonia",
journal = "26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia",
title = "Structural Characteristics and Adsorption Properties of Alkali Activated Blends Ashes/Metakaolin",
pages = "29-29",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11754"
}

Mladenović Nikolić, N., Knežević, S., Ivanović, M. M., Mirković, M., Maletić, M., Kljajević, L.,& Trivunac, K.. (2023). Structural Characteristics and Adsorption Properties of Alkali Activated Blends Ashes/Metakaolin. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
Society of Chemists and Technologists of Macedonia., 29-29.
https://hdl.handle.net/21.15107/rcub_vinar_11754

Mladenović Nikolić N, Knežević S, Ivanović MM, Mirković M, Maletić M, Kljajević L, Trivunac K. Structural Characteristics and Adsorption Properties of Alkali Activated Blends Ashes/Metakaolin. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia. 2023;:29-29.
https://hdl.handle.net/21.15107/rcub_vinar_11754 .

Mladenović Nikolić, Nataša, Knežević, Sanja, Ivanović, Marija M., Mirković, Miljana, Maletić, M., Kljajević, Ljiljana, Trivunac, K., "Structural Characteristics and Adsorption Properties of Alkali Activated Blends Ashes/Metakaolin" in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia (2023):29-29,
https://hdl.handle.net/21.15107/rcub_vinar_11754 .

TY  - CONF
AU  - Ivanović, Marija
AU  - Knežević, Sanja
AU  - Mirković, Miljana
AU  - Kljajević, Ljiljana
AU  - Nenadović, Miloš
AU  - Mladenović Nikolić, Nataša
AU  - Nenadović, Snežana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11756
AB  - Recently, there has been a growing interest in mixing two different systems, organic and inorganic, which would contribute to some improved properties, such as adjustment time, reduced shrinkage, improved mechanical properties and durability. A new class of geopolymer composites with an organic matrix has been developed with the main goal of improving the fire resistance of organic polymers and reducing the production of smoke resulting from their combustion, as well as improving mechanical properties. For the synthesis of hybrid geopolymer materials, metakaolin with the addition of organic phase poly (vinyl alcohol) (PVA) was used as the starting material. For the synthesis of alkaline activator, a solution of NaOH with a molarity of 12 mol / dm3 was used. The chemical composition of the samples was determined by XRF analysis. 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. 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 is far more porous than the basic sample, and we can conclude that we have synthesized a material that shows good mechanical properties.
PB  - Society of Chemists and Technologists of Macedonia
C3  - 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
T1  - Physico-Chemical Properties of Geopolymers Based on Metakaolin with The Addition of Organic Phase PVA
SP  - 32
EP  - 32
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11756
ER  - 

@conference{
author = "Ivanović, Marija and Knežević, Sanja and Mirković, Miljana and Kljajević, Ljiljana and Nenadović, Miloš and Mladenović Nikolić, Nataša and Nenadović, Snežana",
year = "2023",
abstract = "Recently, there has been a growing interest in mixing two different systems, organic and inorganic, which would contribute to some improved properties, such as adjustment time, reduced shrinkage, improved mechanical properties and durability. A new class of geopolymer composites with an organic matrix has been developed with the main goal of improving the fire resistance of organic polymers and reducing the production of smoke resulting from their combustion, as well as improving mechanical properties. For the synthesis of hybrid geopolymer materials, metakaolin with the addition of organic phase poly (vinyl alcohol) (PVA) was used as the starting material. For the synthesis of alkaline activator, a solution of NaOH with a molarity of 12 mol / dm3 was used. The chemical composition of the samples was determined by XRF analysis. 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. 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 is far more porous than the basic sample, and we can conclude that we have synthesized a material that shows good mechanical properties.",
publisher = "Society of Chemists and Technologists of Macedonia",
journal = "26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia",
title = "Physico-Chemical Properties of Geopolymers Based on Metakaolin with The Addition of Organic Phase PVA",
pages = "32-32",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11756"
}

Ivanović, M., Knežević, S., Mirković, M., Kljajević, L., Nenadović, M., Mladenović Nikolić, N.,& Nenadović, S.. (2023). Physico-Chemical Properties of Geopolymers Based on Metakaolin with The Addition of Organic Phase PVA. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
Society of Chemists and Technologists of Macedonia., 32-32.
https://hdl.handle.net/21.15107/rcub_vinar_11756

Ivanović M, Knežević S, Mirković M, Kljajević L, Nenadović M, Mladenović Nikolić N, Nenadović S. Physico-Chemical Properties of Geopolymers Based on Metakaolin with The Addition of Organic Phase PVA. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia. 2023;:32-32.
https://hdl.handle.net/21.15107/rcub_vinar_11756 .

Ivanović, Marija, Knežević, Sanja, Mirković, Miljana, Kljajević, Ljiljana, Nenadović, Miloš, Mladenović Nikolić, Nataša, Nenadović, Snežana, "Physico-Chemical Properties of Geopolymers Based on Metakaolin with The Addition of Organic Phase PVA" in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia (2023):32-32,
https://hdl.handle.net/21.15107/rcub_vinar_11756 .

TY  - CONF
AU  - Kljajević, Ljiljana
AU  - Mladenović Nikolić, Nataša
AU  - Kandić, Aleksandar
AU  - Vukanac, Ivana
AU  - Ivanović, Marija M.
AU  - Knežević, Sanja
AU  - Mirković, Miljana
AU  - Nenadović, Snežana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12091
AB  - Improperly storage of fly ash as industrial wastes has been a cause of land contamination issues. These wastes or by-products have the potential to be used as secondary raw materials in construction, promoting the concept of a circular economy that will avoid land contamination. Here we evaluate radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as fly ash and wood ash are made into 'green cements' such as geopolymers or alkali-activated materials (AAMs). Alkali-activated materials were formed by alkali-activation reaction of wood and fly ash, as a solid precours, and alkali activator solution, sodium hydroxide and sodium silicate. Three differente concentration of alkali solution were used. Determination of radionuclide content was performed by means of gamma-ray spectrometry. The external absorbed gamma dose rate was 68.6-98.1 nGy/h, and external radiation hazard index for alkali-activated material AAM4, AAM6 and AAM12 were 0.544 Bq/kg, 0.575 Bq/kg and 0.403 Bq/kg, respectively. The results of activity concentration measurements in alkali-activated materials indicate potential of their safe application in building constructions. In terms of some the structural characterizations the obtained alkali activated materials were examined.
AB  - Nepravilno skladištenje letećeg pepela kao industrijskog otpada je uzrok problema kontaminacije zemljišta. Ovaj otpad ili nusproizvodi imaju potencijal da se koriste kao sekundarne sirovine u građevinarstvu, promovišući koncept kružne ekonomije kako bi se izbegla kontaminaciju zemljišta. U ovom radu procenjuje se radiološki uticaj na životnu sredinu kada se otpad koji sadrži povišene nivoe prirodnih radionuklida kao što su leteći pepeo i drveni pepeo pretvara u zelene cemente kao što su geopolimeri ili alkalno aktivirani materijali (AAM). Alkalno-aktivirani materijali nastali su reakcijom alkalne aktivacije drvenog i elektrofilterskog pepela, kao čvrstih prekursora, i rastvora alkalnog aktivatora, natrijum hidroksida i natrijum silikata. Korišćene su tri različite koncentracije ratvora alkalnog aktivatora. Određivanje sadržaja radionuklida urađeno je spektrometrijom gama zraka. Jačina apsorbovane doze bila je 68,6-98,1 nGy/h, a Hex (Bq/kg ) za alkalno aktivirane materijale AAM4, AAM6 i AAM12 je bio 0,544 Bq/kg, 0,575 Bq/kg i 0,403 Bq/kg, respektivno. Rezultati merenja koncentracije aktivnosti u alkalno aktiviranim materijalima ukazuju na potencijal njihove bezbedne primene u građevinskim konstrukcijama. Alkalno aktivirani materijali su ispitani i u pogledu nekih strukturnih karakteristika.
PB  - Beograd : Univerzitet u Beogradu, Institut za nuklearne nauke "Vinča"
PB  - Društvo za zaštitu od zračenja Srbije i Crne Gore
C3  - 32. simpozijum DZZSCG : zbornik radova
T1  - Radiological Characterization of Alkali Activated Materials Containing Wood and Fly Ash
T1  - Radiološka karakterizacija alkalno aktivnih materijala koji sadrže drveni i leteći pepeo
SP  - 71
EP  - 79
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12091
ER  - 

@conference{
author = "Kljajević, Ljiljana and Mladenović Nikolić, Nataša and Kandić, Aleksandar and Vukanac, Ivana and Ivanović, Marija M. and Knežević, Sanja and Mirković, Miljana and Nenadović, Snežana",
year = "2023",
abstract = "Improperly storage of fly ash as industrial wastes has been a cause of land contamination issues. These wastes or by-products have the potential to be used as secondary raw materials in construction, promoting the concept of a circular economy that will avoid land contamination. Here we evaluate radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as fly ash and wood ash are made into 'green cements' such as geopolymers or alkali-activated materials (AAMs). Alkali-activated materials were formed by alkali-activation reaction of wood and fly ash, as a solid precours, and alkali activator solution, sodium hydroxide and sodium silicate. Three differente concentration of alkali solution were used. Determination of radionuclide content was performed by means of gamma-ray spectrometry. The external absorbed gamma dose rate was 68.6-98.1 nGy/h, and external radiation hazard index for alkali-activated material AAM4, AAM6 and AAM12 were 0.544 Bq/kg, 0.575 Bq/kg and 0.403 Bq/kg, respectively. The results of activity concentration measurements in alkali-activated materials indicate potential of their safe application in building constructions. In terms of some the structural characterizations the obtained alkali activated materials were examined., Nepravilno skladištenje letećeg pepela kao industrijskog otpada je uzrok problema kontaminacije zemljišta. Ovaj otpad ili nusproizvodi imaju potencijal da se koriste kao sekundarne sirovine u građevinarstvu, promovišući koncept kružne ekonomije kako bi se izbegla kontaminaciju zemljišta. U ovom radu procenjuje se radiološki uticaj na životnu sredinu kada se otpad koji sadrži povišene nivoe prirodnih radionuklida kao što su leteći pepeo i drveni pepeo pretvara u zelene cemente kao što su geopolimeri ili alkalno aktivirani materijali (AAM). Alkalno-aktivirani materijali nastali su reakcijom alkalne aktivacije drvenog i elektrofilterskog pepela, kao čvrstih prekursora, i rastvora alkalnog aktivatora, natrijum hidroksida i natrijum silikata. Korišćene su tri različite koncentracije ratvora alkalnog aktivatora. Određivanje sadržaja radionuklida urađeno je spektrometrijom gama zraka. Jačina apsorbovane doze bila je 68,6-98,1 nGy/h, a Hex (Bq/kg ) za alkalno aktivirane materijale AAM4, AAM6 i AAM12 je bio 0,544 Bq/kg, 0,575 Bq/kg i 0,403 Bq/kg, respektivno. Rezultati merenja koncentracije aktivnosti u alkalno aktiviranim materijalima ukazuju na potencijal njihove bezbedne primene u građevinskim konstrukcijama. Alkalno aktivirani materijali su ispitani i u pogledu nekih strukturnih karakteristika.",
publisher = "Beograd : Univerzitet u Beogradu, Institut za nuklearne nauke "Vinča", Društvo za zaštitu od zračenja Srbije i Crne Gore",
journal = "32. simpozijum DZZSCG : zbornik radova",
title = "Radiological Characterization of Alkali Activated Materials Containing Wood and Fly Ash, Radiološka karakterizacija alkalno aktivnih materijala koji sadrže drveni i leteći pepeo",
pages = "71-79",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12091"
}

Kljajević, L., Mladenović Nikolić, N., Kandić, A., Vukanac, I., Ivanović, M. M., Knežević, S., Mirković, M.,& Nenadović, S.. (2023). Radiological Characterization of Alkali Activated Materials Containing Wood and Fly Ash. in 32. simpozijum DZZSCG : zbornik radova
Beograd : Univerzitet u Beogradu, Institut za nuklearne nauke "Vinča"., 71-79.
https://hdl.handle.net/21.15107/rcub_vinar_12091

Kljajević L, Mladenović Nikolić N, Kandić A, Vukanac I, Ivanović MM, Knežević S, Mirković M, Nenadović S. Radiological Characterization of Alkali Activated Materials Containing Wood and Fly Ash. in 32. simpozijum DZZSCG : zbornik radova. 2023;:71-79.
https://hdl.handle.net/21.15107/rcub_vinar_12091 .

Kljajević, Ljiljana, Mladenović Nikolić, Nataša, Kandić, Aleksandar, Vukanac, Ivana, Ivanović, Marija M., Knežević, Sanja, Mirković, Miljana, Nenadović, Snežana, "Radiological Characterization of Alkali Activated Materials Containing Wood and Fly Ash" in 32. simpozijum DZZSCG : zbornik radova (2023):71-79,
https://hdl.handle.net/21.15107/rcub_vinar_12091 .

TY  - CONF
AU  - Knežević, Sanja
AU  - Nenadović, Miloš
AU  - Potočnik, Jelena
AU  - Kisić, Danilo
AU  - Rajačić, Milica
AU  - Nenadović, Snežana
AU  - Ivanović, Marija
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12326
AB  - This study focused on analyzing samples of aluminosilicate materials in which different percentages of samarium (III)-oxide were incorporated. Basic samples and thermally treated samples at 600 °C were analyzed. Introducing samarium (III)-oxide into the polymer matrix of aluminosilicates has been demonstrated to alter the fundamental structure of aluminosilicate materials. Interestingly, at elevated temperatures, these materials exhibit even more distinctive properties. The gamma ray spectrometric analysis results were used to conduct radiological analysis. Different methods monitor physico-chemical changes within the aluminosilicate materials. By introducing Sm3+ into the aluminosilicate matrix, the basic structure of the aluminosilicate is disturbed. The DRIFT method was used to analyze the structural properties. The analysis of the microstructural properties of the selected samples was carried out using a scanning electron microscope (SEM) and enabled the examination of the fine details of the structure of the materials thermally treated at 600 °C which resulted in the appearance of significant pores and cracks in the material.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - 21st Young Researchers' Conference Materials Sciences and Engineering : program and the book of abstracts
T1  - Radiological and structural analysis of aluminosilicate materials incorporated with samarium (III)-oxide
SP  - 55
EP  - 55
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12326
ER  - 

@conference{
author = "Knežević, Sanja and Nenadović, Miloš and Potočnik, Jelena and Kisić, Danilo and Rajačić, Milica and Nenadović, Snežana and Ivanović, Marija",
year = "2023",
abstract = "This study focused on analyzing samples of aluminosilicate materials in which different percentages of samarium (III)-oxide were incorporated. Basic samples and thermally treated samples at 600 °C were analyzed. Introducing samarium (III)-oxide into the polymer matrix of aluminosilicates has been demonstrated to alter the fundamental structure of aluminosilicate materials. Interestingly, at elevated temperatures, these materials exhibit even more distinctive properties. The gamma ray spectrometric analysis results were used to conduct radiological analysis. Different methods monitor physico-chemical changes within the aluminosilicate materials. By introducing Sm3+ into the aluminosilicate matrix, the basic structure of the aluminosilicate is disturbed. The DRIFT method was used to analyze the structural properties. The analysis of the microstructural properties of the selected samples was carried out using a scanning electron microscope (SEM) and enabled the examination of the fine details of the structure of the materials thermally treated at 600 °C which resulted in the appearance of significant pores and cracks in the material.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "21st Young Researchers' Conference Materials Sciences and Engineering : program and the book of abstracts",
title = "Radiological and structural analysis of aluminosilicate materials incorporated with samarium (III)-oxide",
pages = "55-55",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12326"
}

Knežević, S., Nenadović, M., Potočnik, J., Kisić, D., Rajačić, M., Nenadović, S.,& Ivanović, M.. (2023). Radiological and structural analysis of aluminosilicate materials incorporated with samarium (III)-oxide. in 21st Young Researchers' Conference Materials Sciences and Engineering : program and the book of abstracts
Belgrade : Institute of Technical Sciences of SASA., 55-55.
https://hdl.handle.net/21.15107/rcub_vinar_12326

Knežević S, Nenadović M, Potočnik J, Kisić D, Rajačić M, Nenadović S, Ivanović M. Radiological and structural analysis of aluminosilicate materials incorporated with samarium (III)-oxide. in 21st Young Researchers' Conference Materials Sciences and Engineering : program and the book of abstracts. 2023;:55-55.
https://hdl.handle.net/21.15107/rcub_vinar_12326 .

Knežević, Sanja, Nenadović, Miloš, Potočnik, Jelena, Kisić, Danilo, Rajačić, Milica, Nenadović, Snežana, Ivanović, Marija, "Radiological and structural analysis of aluminosilicate materials incorporated with samarium (III)-oxide" in 21st Young Researchers' Conference Materials Sciences and Engineering : program and the book of abstracts (2023):55-55,
https://hdl.handle.net/21.15107/rcub_vinar_12326 .

TY  - JOUR
AU  - Knežević, Sanja
AU  - Ivanović, Marija
AU  - Stanković, Dalibor M.
AU  - Kisić, Danilo
AU  - Nenadović, Snežana
AU  - Potočnik, Jelena
AU  - Nenadović, Miloš
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11074
AB  - The following investigation presents the thermal treatment of geopolymer at 300 °C, 600 °C and 900 °C. We investigated what happens to the geopolymer base when incorporated with 1% and 5% of neodymium in the form Nd2O3. A total of six samples were synthesized. Geopolymer 1 contained 1% and geopolymer 2 contained 5% Nd2O3, and these samples were treated at 300 °C; then, samples geopolymer 3 and geopolymer 4 also had the same percentage composition of Nd2O3 and were treated at 600 °C, while samples geopolymer 5 and geopolymer 6were treated at 900 °C. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers; however, with increased temperatures, these materials show even more unusual properties. Diffuse reflectance infrared Fourier transform (DRIFT) analysis showed that the intensity of the vibrational band decreases with the increase in temperature during thermal treatment, suggesting alterations in the chemical structure of the geopolymers. Transmission electron microscopy (TEM) analysis showed that the diameter of the nanoparticles containing Al2O3 is in the range 5–10 nm, while larger crystallites range from 30 to 80 nm. Scanning electron microscopy (SEM) analysis revealed that the temperature of the thermal treatment increases to 300 °C and 600 °C; the porosity of geopolymer increases in the form of the appearance of large pores and cracks in material. X-ray photoelectron spectroscopy (XPS) analysis was used to investigate the surface chemistry of geopolymers, including the chemical composition of the surface, the oxidation state of the elements, and the presence of functional groups. The UV/Vis spectra of the synthesized geopolymers doped with Nd3+ show interesting optical properties at 900 °C; the geopolymer matrix completely disintegrates and an amorphous phase with a rare-earth precipitate appears.
T2  - Nanomaterials
T1  - Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium
VL  - 13
IS  - 10
SP  - 1663
DO  - 10.3390/nano13101663
ER  - 

@article{
author = "Knežević, Sanja and Ivanović, Marija and Stanković, Dalibor M. and Kisić, Danilo and Nenadović, Snežana and Potočnik, Jelena and Nenadović, Miloš",
year = "2023",
abstract = "The following investigation presents the thermal treatment of geopolymer at 300 °C, 600 °C and 900 °C. We investigated what happens to the geopolymer base when incorporated with 1% and 5% of neodymium in the form Nd2O3. A total of six samples were synthesized. Geopolymer 1 contained 1% and geopolymer 2 contained 5% Nd2O3, and these samples were treated at 300 °C; then, samples geopolymer 3 and geopolymer 4 also had the same percentage composition of Nd2O3 and were treated at 600 °C, while samples geopolymer 5 and geopolymer 6were treated at 900 °C. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers; however, with increased temperatures, these materials show even more unusual properties. Diffuse reflectance infrared Fourier transform (DRIFT) analysis showed that the intensity of the vibrational band decreases with the increase in temperature during thermal treatment, suggesting alterations in the chemical structure of the geopolymers. Transmission electron microscopy (TEM) analysis showed that the diameter of the nanoparticles containing Al2O3 is in the range 5–10 nm, while larger crystallites range from 30 to 80 nm. Scanning electron microscopy (SEM) analysis revealed that the temperature of the thermal treatment increases to 300 °C and 600 °C; the porosity of geopolymer increases in the form of the appearance of large pores and cracks in material. X-ray photoelectron spectroscopy (XPS) analysis was used to investigate the surface chemistry of geopolymers, including the chemical composition of the surface, the oxidation state of the elements, and the presence of functional groups. The UV/Vis spectra of the synthesized geopolymers doped with Nd3+ show interesting optical properties at 900 °C; the geopolymer matrix completely disintegrates and an amorphous phase with a rare-earth precipitate appears.",
journal = "Nanomaterials",
title = "Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium",
volume = "13",
number = "10",
pages = "1663",
doi = "10.3390/nano13101663"
}

Knežević, S., Ivanović, M., Stanković, D. M., Kisić, D., Nenadović, S., Potočnik, J.,& Nenadović, M.. (2023). Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium. in Nanomaterials, 13(10), 1663.
https://doi.org/10.3390/nano13101663

Knežević S, Ivanović M, Stanković DM, Kisić D, Nenadović S, Potočnik J, Nenadović M. Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium. in Nanomaterials. 2023;13(10):1663.
doi:10.3390/nano13101663 .

Knežević, Sanja, Ivanović, Marija, Stanković, Dalibor M., Kisić, Danilo, Nenadović, Snežana, Potočnik, Jelena, Nenadović, Miloš, "Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium" in Nanomaterials, 13, no. 10 (2023):1663,
https://doi.org/10.3390/nano13101663 . .

TY  - CONF
AU  - Kljajević, Ljiljana
AU  - Nenadović, Miloš
AU  - Ivanović, M.
AU  - Knežević, Sanja
AU  - Mladenović Nikolić, Nataša
AU  - Vukanac, Ivana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11751
AB  - The main goal of this study was the evaluation of physical–chemical, as well as radiological properties of residual materials used for synthesis of alkali activated materials (AAMs) for the possible application as new materials in a civil engineering industry. Also, the purpose of this research was to investigate the hydrophobicity of new alumino-silicate materials and the influence of Si/Al ratio on their surface properties. Contact angle measurement (CAM) as reliable indicator of hydrophobicity was determined for synthesized AAMs using water and ethylene glycol as reference liquids. Alkali-activated materials were synthesized from various precursors: kaolin, bentonite and diatomite. Characterization of phase structure and microstructure was performed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy and Energy-dispersive X-ray (SEM/EDX) spectroscopy. Contact angle measurements confirmed that the alkali-activated materials synthesized from metakaolin are the most porous, which can be explained by the smallest Si/Al ratio. The maximum value of contact angle and free surface energy (110.2 mJ/m2 ) has been achieved for alkali-activated materials synthesized by diatomite (GPMD). Concentration of 40K and radionuclides from the 238U and 232Th decay series in waste precursors, their metaphases and AAM samples synthetized by alkali activation were determined together with corresponding absorbed dose rate (D˙) and the annual effective dose rate. Natural activity concentrations in the alkali-activated materials were found to be lower than that of both residual materials and calcined ones.
PB  - Society of Chemists and Technologists of Macedonia
C3  - 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
T1  - Green Alkali Activated Materials Based on The Different Precursors
SP  - 23
EP  - 23
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11751
ER  - 

@conference{
author = "Kljajević, Ljiljana and Nenadović, Miloš and Ivanović, M. and Knežević, Sanja and Mladenović Nikolić, Nataša and Vukanac, Ivana",
year = "2023",
abstract = "The main goal of this study was the evaluation of physical–chemical, as well as radiological properties of residual materials used for synthesis of alkali activated materials (AAMs) for the possible application as new materials in a civil engineering industry. Also, the purpose of this research was to investigate the hydrophobicity of new alumino-silicate materials and the influence of Si/Al ratio on their surface properties. Contact angle measurement (CAM) as reliable indicator of hydrophobicity was determined for synthesized AAMs using water and ethylene glycol as reference liquids. Alkali-activated materials were synthesized from various precursors: kaolin, bentonite and diatomite. Characterization of phase structure and microstructure was performed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy and Energy-dispersive X-ray (SEM/EDX) spectroscopy. Contact angle measurements confirmed that the alkali-activated materials synthesized from metakaolin are the most porous, which can be explained by the smallest Si/Al ratio. The maximum value of contact angle and free surface energy (110.2 mJ/m2 ) has been achieved for alkali-activated materials synthesized by diatomite (GPMD). Concentration of 40K and radionuclides from the 238U and 232Th decay series in waste precursors, their metaphases and AAM samples synthetized by alkali activation were determined together with corresponding absorbed dose rate (D˙) and the annual effective dose rate. Natural activity concentrations in the alkali-activated materials were found to be lower than that of both residual materials and calcined ones.",
publisher = "Society of Chemists and Technologists of Macedonia",
journal = "26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia",
title = "Green Alkali Activated Materials Based on The Different Precursors",
pages = "23-23",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11751"
}

Kljajević, L., Nenadović, M., Ivanović, M., Knežević, S., Mladenović Nikolić, N.,& Vukanac, I.. (2023). Green Alkali Activated Materials Based on The Different Precursors. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
Society of Chemists and Technologists of Macedonia., 23-23.
https://hdl.handle.net/21.15107/rcub_vinar_11751

Kljajević L, Nenadović M, Ivanović M, Knežević S, Mladenović Nikolić N, Vukanac I. Green Alkali Activated Materials Based on The Different Precursors. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia. 2023;:23-23.
https://hdl.handle.net/21.15107/rcub_vinar_11751 .

Kljajević, Ljiljana, Nenadović, Miloš, Ivanović, M., Knežević, Sanja, Mladenović Nikolić, Nataša, Vukanac, Ivana, "Green Alkali Activated Materials Based on The Different Precursors" in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia (2023):23-23,
https://hdl.handle.net/21.15107/rcub_vinar_11751 .

TY  - CONF
AU  - Knežević, Sanja
AU  - Ivanović, Marija
AU  - Kisić, Danilo
AU  - Nenadović, Snežana
AU  - Potočnik, Jelena
AU  - Nenadović, Miloš
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11748
AB  - The following investigation presents the thermal treatment of geopolymer based on metakaolin, with the addition of 1% and 5% of neodymium in the form Nd2O3, at 300˚C, 600˚C and 900˚C. Six samples were synthesized in total. Samples GT1 and GT2 containing 1% and 5% of Nd2O3, and they were treated at 300˚C, while the samples GT3 and GT4 also had the same percentage composition of Nd2O3 and were treated at 600˚C, and the samples GT5 and GT6 were treated at 900˚C with the same percentage of Nd2O3. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers, however, with increased temperature, these materials show even more unusual properties. DRIFT was employed to investigate the structural properties of thermally treated geopolymers. Additionally, TEM provided further insight into the structural changes induced by thermal treatment and Nd2O3 doping. SEM was used to observe the effect of thermal treatment temperature (300˚C and 600˚C) on geopolymer porosity, which resulted in the appearance of large pores and cracks in the material. The UV/Vis spectra of the synthesized Nd3+ doped geopolymers exhibited attractive optical properties. The photoexcitation of electrons from the valence band to the conduction band in the geopolymer structure is responsible for the absorbance observed at 260 nm, while the minor peaks at slightly longer wavelengths can be linked to Nd3+
PB  - Society of Chemists and Technologists of Macedonia
C3  - 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
T1  - Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium
SP  - 20
EP  - 20
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11748
ER  - 

@conference{
author = "Knežević, Sanja and Ivanović, Marija and Kisić, Danilo and Nenadović, Snežana and Potočnik, Jelena and Nenadović, Miloš",
year = "2023",
abstract = "The following investigation presents the thermal treatment of geopolymer based on metakaolin, with the addition of 1% and 5% of neodymium in the form Nd2O3, at 300˚C, 600˚C and 900˚C. Six samples were synthesized in total. Samples GT1 and GT2 containing 1% and 5% of Nd2O3, and they were treated at 300˚C, while the samples GT3 and GT4 also had the same percentage composition of Nd2O3 and were treated at 600˚C, and the samples GT5 and GT6 were treated at 900˚C with the same percentage of Nd2O3. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers, however, with increased temperature, these materials show even more unusual properties. DRIFT was employed to investigate the structural properties of thermally treated geopolymers. Additionally, TEM provided further insight into the structural changes induced by thermal treatment and Nd2O3 doping. SEM was used to observe the effect of thermal treatment temperature (300˚C and 600˚C) on geopolymer porosity, which resulted in the appearance of large pores and cracks in the material. The UV/Vis spectra of the synthesized Nd3+ doped geopolymers exhibited attractive optical properties. The photoexcitation of electrons from the valence band to the conduction band in the geopolymer structure is responsible for the absorbance observed at 260 nm, while the minor peaks at slightly longer wavelengths can be linked to Nd3+",
publisher = "Society of Chemists and Technologists of Macedonia",
journal = "26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia",
title = "Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium",
pages = "20-20",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11748"
}

Knežević, S., Ivanović, M., Kisić, D., Nenadović, S., Potočnik, J.,& Nenadović, M.. (2023). Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
Society of Chemists and Technologists of Macedonia., 20-20.
https://hdl.handle.net/21.15107/rcub_vinar_11748

Knežević S, Ivanović M, Kisić D, Nenadović S, Potočnik J, Nenadović M. Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia. 2023;:20-20.
https://hdl.handle.net/21.15107/rcub_vinar_11748 .

Knežević, Sanja, Ivanović, Marija, Kisić, Danilo, Nenadović, Snežana, Potočnik, Jelena, Nenadović, Miloš, "Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium" in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia (2023):20-20,
https://hdl.handle.net/21.15107/rcub_vinar_11748 .

TY  - CONF
AU  - Nenadović, Miloš
AU  - Kisić, Danilo
AU  - Ivanović, Marija M.
AU  - Knežević, Sanja
AU  - Nenadović, Snežana
AU  - Kljajević, Ljiljana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11749
AB  - The aim of this study was determination of physical-chemical, radiological and structural characteristics of kaolin, fly ash and the products of alkali-activated as well as thermally treated kaolin (alkali activated materials). Kaolin (raw material) and fly ash (industrial waste) used in the investigation showed the great potential for obtaining alkali activated materials as relatively new products to be used in construction and civil engineering as green cements. Physical-chemical and structural characterization was conducted using X ray diffraction (XRD), Fourier transform infra-red (FTIR) and X ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and High-resolution transmission electron microscopy (HR-TEM). Activity concentration of naturally occurring radionuclides in kaolin, metakaolin, fly ash and alkali activated materials were determined. The absorbed dose rate (D) and the annual effective dose rate (EDR), were calculated in accordance to the UNSCEAR 2000 report. Kaolin was thermally treated on 750°C, and specific activity of natural radionuclides in metakaolin increased up to 1.6, while specific activities in alkali activated materials were significantly reduced.
PB  - Society of Chemists and Technologists of Macedonia
C3  - 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
T1  - Physicochemical, Radiological and Structural Properties of Alkali Activated Materials – Future Trends and Applications
SP  - 21
EP  - 21
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11749
ER  - 

@conference{
author = "Nenadović, Miloš and Kisić, Danilo and Ivanović, Marija M. and Knežević, Sanja and Nenadović, Snežana and Kljajević, Ljiljana",
year = "2023",
abstract = "The aim of this study was determination of physical-chemical, radiological and structural characteristics of kaolin, fly ash and the products of alkali-activated as well as thermally treated kaolin (alkali activated materials). Kaolin (raw material) and fly ash (industrial waste) used in the investigation showed the great potential for obtaining alkali activated materials as relatively new products to be used in construction and civil engineering as green cements. Physical-chemical and structural characterization was conducted using X ray diffraction (XRD), Fourier transform infra-red (FTIR) and X ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and High-resolution transmission electron microscopy (HR-TEM). Activity concentration of naturally occurring radionuclides in kaolin, metakaolin, fly ash and alkali activated materials were determined. The absorbed dose rate (D) and the annual effective dose rate (EDR), were calculated in accordance to the UNSCEAR 2000 report. Kaolin was thermally treated on 750°C, and specific activity of natural radionuclides in metakaolin increased up to 1.6, while specific activities in alkali activated materials were significantly reduced.",
publisher = "Society of Chemists and Technologists of Macedonia",
journal = "26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia",
title = "Physicochemical, Radiological and Structural Properties of Alkali Activated Materials – Future Trends and Applications",
pages = "21-21",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11749"
}

Nenadović, M., Kisić, D., Ivanović, M. M., Knežević, S., Nenadović, S.,& Kljajević, L.. (2023). Physicochemical, Radiological and Structural Properties of Alkali Activated Materials – Future Trends and Applications. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia
Society of Chemists and Technologists of Macedonia., 21-21.
https://hdl.handle.net/21.15107/rcub_vinar_11749

Nenadović M, Kisić D, Ivanović MM, Knežević S, Nenadović S, Kljajević L. Physicochemical, Radiological and Structural Properties of Alkali Activated Materials – Future Trends and Applications. in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia. 2023;:21-21.
https://hdl.handle.net/21.15107/rcub_vinar_11749 .

Nenadović, Miloš, Kisić, Danilo, Ivanović, Marija M., Knežević, Sanja, Nenadović, Snežana, Kljajević, Ljiljana, "Physicochemical, Radiological and Structural Properties of Alkali Activated Materials – Future Trends and Applications" in 26th Congress of the Society of Chemists and Technologists of Macedonia : the book of abstracts; September 20-23, Ohrid, Macedonia (2023):21-21,
https://hdl.handle.net/21.15107/rcub_vinar_11749 .

TY  - CONF
AU  - Knežević, Sanja
AU  - Ivanović, Marija
AU  - Kljajević, Ljiljana M.
AU  - Nenadović, Snežana S.
AU  - Potočnik, Jelena
AU  - Mirković, Miljana M.
AU  - Nenadović, Miloš
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10803
AB  - Rare earth oxides have been broadly utilised in different research areas due to their unique properties. This research aims to examine the effect of Nd and Sm in the form of oxide addition in the metakaolin-based geopolymer matrix. Metakaolin-based geopolymers with the addition of different percentages of Sm2O3 and Nd2O3 (S1-S6) were synthesised. Samples contained 0.1% Sm; 1% Sm; 5% Sm, and 0.1% Nd, 1% Nd, and 5% Nd. The focus was on monitoring the polymerisation process using the DRIFT method for 7, 14, 21 and 28 days. The phase composition of the samples was confirmed by the XRD method, while the morphology of the samples was analysed by SEM analysis. After 28 days, due to the polymerisation process, the binding of Neodymium and Samarium ions were incorporated into the structure.
PB  - Belgrade : Serbian Ceramic Society
C3  - Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade
T1  - Crosslinking of rare earth ions into aluminosilicate inorganic polymer
SP  - 72
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10803
ER  - 

@conference{
author = "Knežević, Sanja and Ivanović, Marija and Kljajević, Ljiljana M. and Nenadović, Snežana S. and Potočnik, Jelena and Mirković, Miljana M. and Nenadović, Miloš",
year = "2022",
abstract = "Rare earth oxides have been broadly utilised in different research areas due to their unique properties. This research aims to examine the effect of Nd and Sm in the form of oxide addition in the metakaolin-based geopolymer matrix. Metakaolin-based geopolymers with the addition of different percentages of Sm2O3 and Nd2O3 (S1-S6) were synthesised. Samples contained 0.1% Sm; 1% Sm; 5% Sm, and 0.1% Nd, 1% Nd, and 5% Nd. The focus was on monitoring the polymerisation process using the DRIFT method for 7, 14, 21 and 28 days. The phase composition of the samples was confirmed by the XRD method, while the morphology of the samples was analysed by SEM analysis. After 28 days, due to the polymerisation process, the binding of Neodymium and Samarium ions were incorporated into the structure.",
publisher = "Belgrade : Serbian Ceramic Society",
journal = "Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade",
title = "Crosslinking of rare earth ions into aluminosilicate inorganic polymer",
pages = "72",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10803"
}

Knežević, S., Ivanović, M., Kljajević, L. M., Nenadović, S. S., Potočnik, J., Mirković, M. M.,& Nenadović, M.. (2022). Crosslinking of rare earth ions into aluminosilicate inorganic polymer. in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade
Belgrade : Serbian Ceramic Society., 72.
https://hdl.handle.net/21.15107/rcub_vinar_10803

Knežević S, Ivanović M, Kljajević LM, Nenadović SS, Potočnik J, Mirković MM, Nenadović M. Crosslinking of rare earth ions into aluminosilicate inorganic polymer. in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade. 2022;:72.
https://hdl.handle.net/21.15107/rcub_vinar_10803 .

Knežević, Sanja, Ivanović, Marija, Kljajević, Ljiljana M., Nenadović, Snežana S., Potočnik, Jelena, Mirković, Miljana M., Nenadović, Miloš, "Crosslinking of rare earth ions into aluminosilicate inorganic polymer" in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade (2022):72,
https://hdl.handle.net/21.15107/rcub_vinar_10803 .

TY  - CONF
AU  - Mladenović Nikolić, Nataša
AU  - Knežević, Sanja
AU  - Ivanović, Marija
AU  - Nenadović, Snežana S.
AU  - Mirković, Miljana M.
AU  - Pavlović, Vladimir B.
AU  - Kljajević, Ljiljana M.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10805
AB  - Presented research related to the structure of a different kind of alumosilicate matrix of alkali activated materials (AAM). Fly ash (FA), wood ash (WA) and metakaolin (MK) were used as a solid precursors of final AAM samples. Synthesis of the AAM was conducted by mixing in a determined ratio solid precursors and an alkali activator (sodium silicate solution, NaOH solutions concentration-4 mol dm-3 and 12 mol dm-3 ). AAM samples were synthesized by a two-component system: MK/FA and WA/MK. The ratio of components MK/FA and WA/MK was 0.9. The AAM samples were cured at determined laboratory conditions (time, temperature, humidity, aging) in covering mold. The X-ray diffraction (XRD), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and Scanning Electron Microscopy (SEM) were provided to the samples after twenty-eight days of geopolymerization process. The higher background of both MK/FA and WA/MK based AAM samples indicates the achievement of amorphization during the geopolymerization process. In investigated samples, the characteristic stretching asymmetric vibrations C=O, and carbonate vibrations were expected in highly alkaline FA/MK and WA/MK mixture. SEM morphology of all AAM samples noticed an amorphous phase with irregularly distributed, agglomerated particles, and some crystal phases originating from raw materials on the surface alumosilicate matrix.
PB  - Belgrade : Serbian Ceramic Society
C3  - Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade
T1  - Aluminosilicate matrix of alkali activated mixture of metakaolin/fly ash and wood ash/metakaolin
SP  - 73
EP  - 74
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10805
ER  - 

@conference{
author = "Mladenović Nikolić, Nataša and Knežević, Sanja and Ivanović, Marija and Nenadović, Snežana S. and Mirković, Miljana M. and Pavlović, Vladimir B. and Kljajević, Ljiljana M.",
year = "2022",
abstract = "Presented research related to the structure of a different kind of alumosilicate matrix of alkali activated materials (AAM). Fly ash (FA), wood ash (WA) and metakaolin (MK) were used as a solid precursors of final AAM samples. Synthesis of the AAM was conducted by mixing in a determined ratio solid precursors and an alkali activator (sodium silicate solution, NaOH solutions concentration-4 mol dm-3 and 12 mol dm-3 ). AAM samples were synthesized by a two-component system: MK/FA and WA/MK. The ratio of components MK/FA and WA/MK was 0.9. The AAM samples were cured at determined laboratory conditions (time, temperature, humidity, aging) in covering mold. The X-ray diffraction (XRD), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and Scanning Electron Microscopy (SEM) were provided to the samples after twenty-eight days of geopolymerization process. The higher background of both MK/FA and WA/MK based AAM samples indicates the achievement of amorphization during the geopolymerization process. In investigated samples, the characteristic stretching asymmetric vibrations C=O, and carbonate vibrations were expected in highly alkaline FA/MK and WA/MK mixture. SEM morphology of all AAM samples noticed an amorphous phase with irregularly distributed, agglomerated particles, and some crystal phases originating from raw materials on the surface alumosilicate matrix.",
publisher = "Belgrade : Serbian Ceramic Society",
journal = "Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade",
title = "Aluminosilicate matrix of alkali activated mixture of metakaolin/fly ash and wood ash/metakaolin",
pages = "73-74",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10805"
}

Mladenović Nikolić, N., Knežević, S., Ivanović, M., Nenadović, S. S., Mirković, M. M., Pavlović, V. B.,& Kljajević, L. M.. (2022). Aluminosilicate matrix of alkali activated mixture of metakaolin/fly ash and wood ash/metakaolin. in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade
Belgrade : Serbian Ceramic Society., 73-74.
https://hdl.handle.net/21.15107/rcub_vinar_10805

Mladenović Nikolić N, Knežević S, Ivanović M, Nenadović SS, Mirković MM, Pavlović VB, Kljajević LM. Aluminosilicate matrix of alkali activated mixture of metakaolin/fly ash and wood ash/metakaolin. in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade. 2022;:73-74.
https://hdl.handle.net/21.15107/rcub_vinar_10805 .

Mladenović Nikolić, Nataša, Knežević, Sanja, Ivanović, Marija, Nenadović, Snežana S., Mirković, Miljana M., Pavlović, Vladimir B., Kljajević, Ljiljana M., "Aluminosilicate matrix of alkali activated mixture of metakaolin/fly ash and wood ash/metakaolin" in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade (2022):73-74,
https://hdl.handle.net/21.15107/rcub_vinar_10805 .

TY  - CONF
AU  - Knežević, Sanja
AU  - Kosanović, Dejana
AU  - Živković, Irena
AU  - Ilić, Vesna
AU  - Dragačević, Luka
AU  - Hajduković, Ljiljana
AU  - Minić, Rajna
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11575
AB  - Streptococcus pneumoniae, the pneumococcus is an important human pathogen. It possesses a capsule which has been thoroughly studied, since it is an important factor in virulence. In this work S. pneumoniae ATCC 6301, belonging to Serogroup 1, was used as a model organism to determine the levels of different IgG isotypes specific to this bacterium in different sex and age groups. For this purpose an in‐house ELISA was used. Although IgG2 is a major antibacterial antibody subclass, acting against polysaccharide antigens, the level of pneumococcus‐specific IgG2 did not differ from the level of IgG2 specific to several tested lactic acid bacteria (LAB). On the other hand pneumococcus specific IgG1 level was significantly higher to the level of LAB specific IgG1. This is most likely a consequence of previous encounters with pathogenic pneumococcal microorganism and a distinguishing characteristic of this encounter. By analyzing different sex and age groups we found significantly lower anti‐pneumococcus IgG1 levels in men, implying lower protection against invasion with pneumococcus, which possibly translates to other encapsulated bacteria. The Covid‐19 pandemic has identified males as being at increased risk of hospital admission and death and lower levels of anti‐pneumococcus antibodies might be a contributing factor. Hence, we advocate the immunization with conjugate pneumococcal vaccines in male individuals, especially over the age of 50.
PB  - Wiley
C3  - European Journal of Immunology, Virtual ECI 2021 : Abstract Book
T1  - Report on lower anti-pneumococcus IgG1 levels in men, especially over the age of fifty
VL  - 51
IS  - Supplement S1
SP  - 337
EP  - 337
DO  - 10.1002/eji.202170200
ER  - 

@conference{
author = "Knežević, Sanja and Kosanović, Dejana and Živković, Irena and Ilić, Vesna and Dragačević, Luka and Hajduković, Ljiljana and Minić, Rajna",
year = "2021",
abstract = "Streptococcus pneumoniae, the pneumococcus is an important human pathogen. It possesses a capsule which has been thoroughly studied, since it is an important factor in virulence. In this work S. pneumoniae ATCC 6301, belonging to Serogroup 1, was used as a model organism to determine the levels of different IgG isotypes specific to this bacterium in different sex and age groups. For this purpose an in‐house ELISA was used. Although IgG2 is a major antibacterial antibody subclass, acting against polysaccharide antigens, the level of pneumococcus‐specific IgG2 did not differ from the level of IgG2 specific to several tested lactic acid bacteria (LAB). On the other hand pneumococcus specific IgG1 level was significantly higher to the level of LAB specific IgG1. This is most likely a consequence of previous encounters with pathogenic pneumococcal microorganism and a distinguishing characteristic of this encounter. By analyzing different sex and age groups we found significantly lower anti‐pneumococcus IgG1 levels in men, implying lower protection against invasion with pneumococcus, which possibly translates to other encapsulated bacteria. The Covid‐19 pandemic has identified males as being at increased risk of hospital admission and death and lower levels of anti‐pneumococcus antibodies might be a contributing factor. Hence, we advocate the immunization with conjugate pneumococcal vaccines in male individuals, especially over the age of 50.",
publisher = "Wiley",
journal = "European Journal of Immunology, Virtual ECI 2021 : Abstract Book",
title = "Report on lower anti-pneumococcus IgG1 levels in men, especially over the age of fifty",
volume = "51",
number = "Supplement S1",
pages = "337-337",
doi = "10.1002/eji.202170200"
}

Knežević, S., Kosanović, D., Živković, I., Ilić, V., Dragačević, L., Hajduković, L.,& Minić, R.. (2021). Report on lower anti-pneumococcus IgG1 levels in men, especially over the age of fifty. in European Journal of Immunology, Virtual ECI 2021 : Abstract Book
Wiley., 51(Supplement S1), 337-337.
https://doi.org/10.1002/eji.202170200

Knežević S, Kosanović D, Živković I, Ilić V, Dragačević L, Hajduković L, Minić R. Report on lower anti-pneumococcus IgG1 levels in men, especially over the age of fifty. in European Journal of Immunology, Virtual ECI 2021 : Abstract Book. 2021;51(Supplement S1):337-337.
doi:10.1002/eji.202170200 .

Knežević, Sanja, Kosanović, Dejana, Živković, Irena, Ilić, Vesna, Dragačević, Luka, Hajduković, Ljiljana, Minić, Rajna, "Report on lower anti-pneumococcus IgG1 levels in men, especially over the age of fifty" in European Journal of Immunology, Virtual ECI 2021 : Abstract Book, 51, no. Supplement S1 (2021):337-337,
https://doi.org/10.1002/eji.202170200 . .