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  - Đurašević, Mirjana M.
AU  - Čeliković, Igor T.
AU  - Kandić, Irina
AU  - Milanović, Tamara
AU  - Samolov, Aleksandra
AU  - Mladenović Nikolić, Nataša
AU  - Kandić, Aleksandar
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11794
AB  - Fourteen samples of nine different species were collected in the region of Fruška gora, the suburban areas of Belgrade, and the vicinity of Vlasina Lake (Serbia) have been analyzed from the radiological point of view. Specific activities of radionuclides 210Pb, 137Cs, and 40K were measured using a semiconductor HPGe spectrometer system in these wild mushroom samples. The activity concentrations of all measured dried wild mushrooms are for 210Pb: between 2.05 Bq/kg and 9.74 Bq/kg; for 137Cs: between < 0.2 Bq/kg and 19.3 Bq/kg; for 40K between 704 Bq/kg and 2530 Bq/kg. The total individual annual effective doses due to ingestion of 210Pb, 137Cs, and 40K radionuclides within a 0.5 kg dry mass of the wild mushrooms is between 3.99 µSv and 10.81 µSv, and are much lower than the recommended level for the public (1 mSv/y).
PB  - University of Belgrade, Technical Faculty in Bor
C3  - EcoTER’23 : 30th International Conference Ecological Truth and Environmental Research : Proceedings
T1  - Activity Concentrations of 210Pb, 137Cs, and 40K In Wild Mushrooms From Serbia and Their Effective Dose to Ingestion
SP  - 69
EP  - 74
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11794
ER  - 

@conference{
author = "Đurašević, Mirjana M. and Čeliković, Igor T. and Kandić, Irina and Milanović, Tamara and Samolov, Aleksandra and Mladenović Nikolić, Nataša and Kandić, Aleksandar",
year = "2023",
abstract = "Fourteen samples of nine different species were collected in the region of Fruška gora, the suburban areas of Belgrade, and the vicinity of Vlasina Lake (Serbia) have been analyzed from the radiological point of view. Specific activities of radionuclides 210Pb, 137Cs, and 40K were measured using a semiconductor HPGe spectrometer system in these wild mushroom samples. The activity concentrations of all measured dried wild mushrooms are for 210Pb: between 2.05 Bq/kg and 9.74 Bq/kg; for 137Cs: between < 0.2 Bq/kg and 19.3 Bq/kg; for 40K between 704 Bq/kg and 2530 Bq/kg. The total individual annual effective doses due to ingestion of 210Pb, 137Cs, and 40K radionuclides within a 0.5 kg dry mass of the wild mushrooms is between 3.99 µSv and 10.81 µSv, and are much lower than the recommended level for the public (1 mSv/y).",
publisher = "University of Belgrade, Technical Faculty in Bor",
journal = "EcoTER’23 : 30th International Conference Ecological Truth and Environmental Research : Proceedings",
title = "Activity Concentrations of 210Pb, 137Cs, and 40K In Wild Mushrooms From Serbia and Their Effective Dose to Ingestion",
pages = "69-74",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11794"
}

Đurašević, M. M., Čeliković, I. T., Kandić, I., Milanović, T., Samolov, A., Mladenović Nikolić, N.,& Kandić, A.. (2023). Activity Concentrations of 210Pb, 137Cs, and 40K In Wild Mushrooms From Serbia and Their Effective Dose to Ingestion. in EcoTER’23 : 30th International Conference Ecological Truth and Environmental Research : Proceedings
University of Belgrade, Technical Faculty in Bor., 69-74.
https://hdl.handle.net/21.15107/rcub_vinar_11794

Đurašević MM, Čeliković IT, Kandić I, Milanović T, Samolov A, Mladenović Nikolić N, Kandić A. Activity Concentrations of 210Pb, 137Cs, and 40K In Wild Mushrooms From Serbia and Their Effective Dose to Ingestion. in EcoTER’23 : 30th International Conference Ecological Truth and Environmental Research : Proceedings. 2023;:69-74.
https://hdl.handle.net/21.15107/rcub_vinar_11794 .

Đurašević, Mirjana M., Čeliković, Igor T., Kandić, Irina, Milanović, Tamara, Samolov, Aleksandra, Mladenović Nikolić, Nataša, Kandić, Aleksandar, "Activity Concentrations of 210Pb, 137Cs, and 40K In Wild Mushrooms From Serbia and Their Effective Dose to Ingestion" in EcoTER’23 : 30th International Conference Ecological Truth and Environmental Research : Proceedings (2023):69-74,
https://hdl.handle.net/21.15107/rcub_vinar_11794 .

TY  - CONF
AU  - Mladenović Nikolić, Nataša
AU  - Trivunac, Katarina
AU  - Nenadović, Miloš
AU  - Dolenec, Sabina
AU  - Mrak, Maruša
AU  - Vukanac, Ivana
AU  - Nenadović, Snežana
AU  - Kljajević, Ljiljana M.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12174
AB  - In this study, fly ash (FA) from the active and passive cassette TENT A (Nikola Tesla power plant, Obrenovac) is characterized from physicochemical and radiological aspects.Samples of FA consisted of amorphous phase followed by quartz, mullite, plagioclase, K-feldspar, hematite and calcite. As indicated by laser granulometry, the fraction D50 of investigated samples are about 80μm, so based on the above, they belong to coarse ashes.Very important parameter which defines chemical composition of the fly ash as precursor material of clinker or alkali activated materialsis presence of organic matter which is expressed by total organic content (TOC).Assessment of radiation exposure during coal combustion depends on the concentration of radioactive elements in the coal and in the resulting fly ash. Fly ash as industrial waste contains certain concentrations of natural radionuclides that are considered naturally occurring radioactive materials (NORM). The results showed that fly ash has satisfactory radiological properties and can be used as an addition to clinkers, but also as a potential precursor of a new class of alkaline activated materials that can be used in the construction sector.
AB  - Procena izloženosti zračenju pri sagorevanju uglja zavisi od koncentracije radioaktivnih elemenata u uglju i u letećem pepelu koji nastaje. Uzorci letećeg pepela se sastoje od amorfne faze praćene kvarcom, mulitom, plagioklasom, K-feldspatom, hematinom, kalcitom. Kao rezultat laserske granulometrije, frakcija D50 za ispitivane uzorke je približno 80 μm, tako da na osnovu navedenog, leteći pepeli predstavljaju pepele krupnih čestica. Veoma važan parametar je prisustvo organske materije koje se izražava ukupnim organskim sadržajem. Leteći pepeli kao industrijski ostaci sadrže određene koncentracije prirodnih radionuklida koji se smatraju prirodnim radioaktivnim materijalima (NORM). U ovojm istraživanju, leteći pepeo iz aktivne i pasivne kasete TENT A (termoelektrana Nikola Tesla, Obrenovac) karakteriše se sa radiološkog i fizičko-hemijskog aspekta. Rezultati su pokazali da leteći pepeo ima zadovoljavajuća radiološka svojstva i da se može koristiti kao dodatak klinkerima, ali i kao potencijalni precursor nove klase alkalno aktiviranih materijala koji se mogu primeniti u građevinskom sektoru.
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  - Fly-Ash for Usage in the Building Material Industry
T1  - Upotreba letećeg pepela u industriji građevinskog materijala
SP  - 128
EP  - 136
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12174
ER  - 

@conference{
author = "Mladenović Nikolić, Nataša and Trivunac, Katarina and Nenadović, Miloš and Dolenec, Sabina and Mrak, Maruša and Vukanac, Ivana and Nenadović, Snežana and Kljajević, Ljiljana M.",
year = "2023",
abstract = "In this study, fly ash (FA) from the active and passive cassette TENT A (Nikola Tesla power plant, Obrenovac) is characterized from physicochemical and radiological aspects.Samples of FA consisted of amorphous phase followed by quartz, mullite, plagioclase, K-feldspar, hematite and calcite. As indicated by laser granulometry, the fraction D50 of investigated samples are about 80μm, so based on the above, they belong to coarse ashes.Very important parameter which defines chemical composition of the fly ash as precursor material of clinker or alkali activated materialsis presence of organic matter which is expressed by total organic content (TOC).Assessment of radiation exposure during coal combustion depends on the concentration of radioactive elements in the coal and in the resulting fly ash. Fly ash as industrial waste contains certain concentrations of natural radionuclides that are considered naturally occurring radioactive materials (NORM). The results showed that fly ash has satisfactory radiological properties and can be used as an addition to clinkers, but also as a potential precursor of a new class of alkaline activated materials that can be used in the construction sector., Procena izloženosti zračenju pri sagorevanju uglja zavisi od koncentracije radioaktivnih elemenata u uglju i u letećem pepelu koji nastaje. Uzorci letećeg pepela se sastoje od amorfne faze praćene kvarcom, mulitom, plagioklasom, K-feldspatom, hematinom, kalcitom. Kao rezultat laserske granulometrije, frakcija D50 za ispitivane uzorke je približno 80 μm, tako da na osnovu navedenog, leteći pepeli predstavljaju pepele krupnih čestica. Veoma važan parametar je prisustvo organske materije koje se izražava ukupnim organskim sadržajem. Leteći pepeli kao industrijski ostaci sadrže određene koncentracije prirodnih radionuklida koji se smatraju prirodnim radioaktivnim materijalima (NORM). U ovojm istraživanju, leteći pepeo iz aktivne i pasivne kasete TENT A (termoelektrana Nikola Tesla, Obrenovac) karakteriše se sa radiološkog i fizičko-hemijskog aspekta. Rezultati su pokazali da leteći pepeo ima zadovoljavajuća radiološka svojstva i da se može koristiti kao dodatak klinkerima, ali i kao potencijalni precursor nove klase alkalno aktiviranih materijala koji se mogu primeniti u građevinskom sektoru.",
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 = "Fly-Ash for Usage in the Building Material Industry, Upotreba letećeg pepela u industriji građevinskog materijala",
pages = "128-136",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12174"
}

Mladenović Nikolić, N., Trivunac, K., Nenadović, M., Dolenec, S., Mrak, M., Vukanac, I., Nenadović, S.,& Kljajević, L. M.. (2023). Fly-Ash for Usage in the Building Material Industry. in 32. simpozijum DZZSCG : zbornik radova
Beograd : Univerzitet u Beogradu, Institut za nuklearne nauke "Vinča"., 128-136.
https://hdl.handle.net/21.15107/rcub_vinar_12174

Mladenović Nikolić N, Trivunac K, Nenadović M, Dolenec S, Mrak M, Vukanac I, Nenadović S, Kljajević LM. Fly-Ash for Usage in the Building Material Industry. in 32. simpozijum DZZSCG : zbornik radova. 2023;:128-136.
https://hdl.handle.net/21.15107/rcub_vinar_12174 .

Mladenović Nikolić, Nataša, Trivunac, Katarina, Nenadović, Miloš, Dolenec, Sabina, Mrak, Maruša, Vukanac, Ivana, Nenadović, Snežana, Kljajević, Ljiljana M., "Fly-Ash for Usage in the Building Material Industry" in 32. simpozijum DZZSCG : zbornik radova (2023):128-136,
https://hdl.handle.net/21.15107/rcub_vinar_12174 .

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  - JOUR
AU  - Mladenović-Nikolić, Nataša
AU  - Kandić, Aleksandar
AU  - Trivunac, Katarina V.
AU  - Mirković, Miljana M.
AU  - Vukanac, Ivana
AU  - Nenadović, Snežana S.
AU  - Kljajević, Ljiljana M.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10480
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.
T2  - Sustainability
T1  - Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends
VL  - 14
IS  - 20
SP  - 12960
DO  - 10.3390/su142012960
ER  - 

@article{
author = "Mladenović-Nikolić, Nataša and Kandić, Aleksandar and Trivunac, Katarina V. and Mirković, Miljana M. and Vukanac, Ivana 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.",
journal = "Sustainability",
title = "Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends",
volume = "14",
number = "20",
pages = "12960",
doi = "10.3390/su142012960"
}

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

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

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

TY  - JOUR
AU  - Kljajević, Ljiljana M.
AU  - Nenadović, Miloš
AU  - Ivanović, Marija M.
AU  - Bučevac, Dušan
AU  - Mirković, Miljana M.
AU  - Mladenović-Nikolić, Nataša
AU  - Nenadović, Snežana S.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10635
AB  - In this paper, raw natural metakaolin (MK, Serbia) clay was used as a starting material for the synthesis of geopolymers for thermal treatment. Metakaolin was obtained by calcination of kaolin at 750 °C for 1 h while geopolymer samples were calcined at 900 °C, which is the key transition temperature. Metakaolin was activated by a solution of NaOH of various concentrations and sodium silicate. During the controlled heat treatment, the geopolymer samples began to melt slightly and coagulate locally. The high-temperature exposure of geopolymer samples (900 °C) caused a significant reduction in oxygen, and even more sodium, which led to the formation of a complex porous structure. As the concentration of NaOH (6 mol dm−3 and 8 mol dm−3) increased, new semi-crystalline phases of nepheline and sanidine were formed. Thermal properties were increasingly used to better understand and improve the properties of geopolymers at high temperatures. Temperature changes were monitored by simultaneous use of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The loss of mass of the investigated samples at 900 °C was in the range of 8–16%. Thermal treatment of geopolymers at 900 °C did not have much effect on the change in compressive strength of investigated samples. The results of thermal treatment of geopolymers at 900 °C showed that this is approximately the temperature at which the structure of the geopolymer turns into a ceramic-like structure. All investigated properties of the geopolymers are closely connected to the precursors and the constituents of the geopolymers.
T2  - Gels
T1  - Heat Treatment of Geopolymer Samples Obtained by Varying Concentration of Sodium Hydroxide as Constituent of Alkali Activator
VL  - 8
SP  - 333
DO  - 10.3390/gels8060333
ER  - 

@article{
author = "Kljajević, Ljiljana M. and Nenadović, Miloš and Ivanović, Marija M. and Bučevac, Dušan and Mirković, Miljana M. and Mladenović-Nikolić, Nataša and Nenadović, Snežana S.",
year = "2022",
abstract = "In this paper, raw natural metakaolin (MK, Serbia) clay was used as a starting material for the synthesis of geopolymers for thermal treatment. Metakaolin was obtained by calcination of kaolin at 750 °C for 1 h while geopolymer samples were calcined at 900 °C, which is the key transition temperature. Metakaolin was activated by a solution of NaOH of various concentrations and sodium silicate. During the controlled heat treatment, the geopolymer samples began to melt slightly and coagulate locally. The high-temperature exposure of geopolymer samples (900 °C) caused a significant reduction in oxygen, and even more sodium, which led to the formation of a complex porous structure. As the concentration of NaOH (6 mol dm−3 and 8 mol dm−3) increased, new semi-crystalline phases of nepheline and sanidine were formed. Thermal properties were increasingly used to better understand and improve the properties of geopolymers at high temperatures. Temperature changes were monitored by simultaneous use of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The loss of mass of the investigated samples at 900 °C was in the range of 8–16%. Thermal treatment of geopolymers at 900 °C did not have much effect on the change in compressive strength of investigated samples. The results of thermal treatment of geopolymers at 900 °C showed that this is approximately the temperature at which the structure of the geopolymer turns into a ceramic-like structure. All investigated properties of the geopolymers are closely connected to the precursors and the constituents of the geopolymers.",
journal = "Gels",
title = "Heat Treatment of Geopolymer Samples Obtained by Varying Concentration of Sodium Hydroxide as Constituent of Alkali Activator",
volume = "8",
pages = "333",
doi = "10.3390/gels8060333"
}

Kljajević, L. M., Nenadović, M., Ivanović, M. M., Bučevac, D., Mirković, M. M., Mladenović-Nikolić, N.,& Nenadović, S. S.. (2022). Heat Treatment of Geopolymer Samples Obtained by Varying Concentration of Sodium Hydroxide as Constituent of Alkali Activator. in Gels, 8, 333.
https://doi.org/10.3390/gels8060333

Kljajević LM, Nenadović M, Ivanović MM, Bučevac D, Mirković MM, Mladenović-Nikolić N, Nenadović SS. Heat Treatment of Geopolymer Samples Obtained by Varying Concentration of Sodium Hydroxide as Constituent of Alkali Activator. in Gels. 2022;8:333.
doi:10.3390/gels8060333 .

Kljajević, Ljiljana M., Nenadović, Miloš, Ivanović, Marija M., Bučevac, Dušan, Mirković, Miljana M., Mladenović-Nikolić, Nataša, Nenadović, Snežana S., "Heat Treatment of Geopolymer Samples Obtained by Varying Concentration of Sodium Hydroxide as Constituent of Alkali Activator" in Gels, 8 (2022):333,
https://doi.org/10.3390/gels8060333 . .

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  - JOUR
AU  - Kljajević, Ljiljana M.
AU  - Nenadović, Miloš
AU  - Petković, Marijana
AU  - Bučevac, Dušan
AU  - Pavlović, Vladimir B.
AU  - Mladenović-Nikolić, Nataša
AU  - Nenadović, Snežana B.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10246
AB  - The effect of zircon (ZrSiO4) on the physico-chemical and mechanical properties of geopolymer/zircon composites was examined in this study. Four geopolymer/zircon composites containing 10, 20, 30 and 40 wt.% zircon were prepared from metakaolin with alkali activators. Characterization of the obtained geopolymers was performed by X-ray diffraction (XRD), Scanning electron microscope (SEM-EDS), Fourier transform infrared spectroscopy (FTIR) and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). XRD results did not confirmed the formation of interconnected phases between added zircon, starting aluminum silicates and alkali activators. Compressive strength of prepared geopolymer was examined. The maximum obtained compressive strength of 70.15 MPa was measured in sample containing the smallest fraction of zircon, i.e., 10 wt.%. Addition of larger amount of zircon (20 wt.%) hinders the progress of geopolymerization reaction and consequently decreases compressive strength.
T2  - Science of Sintering
T1  - Physico-chemical and mechanical properties of geopolymer/zircon composites
VL  - 54
IS  - 1
SP  - 11
EP  - 24
DO  - 10.2298/SOS2201011K
ER  - 

@article{
author = "Kljajević, Ljiljana M. and Nenadović, Miloš and Petković, Marijana and Bučevac, Dušan and Pavlović, Vladimir B. and Mladenović-Nikolić, Nataša and Nenadović, Snežana B.",
year = "2022",
abstract = "The effect of zircon (ZrSiO4) on the physico-chemical and mechanical properties of geopolymer/zircon composites was examined in this study. Four geopolymer/zircon composites containing 10, 20, 30 and 40 wt.% zircon were prepared from metakaolin with alkali activators. Characterization of the obtained geopolymers was performed by X-ray diffraction (XRD), Scanning electron microscope (SEM-EDS), Fourier transform infrared spectroscopy (FTIR) and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). XRD results did not confirmed the formation of interconnected phases between added zircon, starting aluminum silicates and alkali activators. Compressive strength of prepared geopolymer was examined. The maximum obtained compressive strength of 70.15 MPa was measured in sample containing the smallest fraction of zircon, i.e., 10 wt.%. Addition of larger amount of zircon (20 wt.%) hinders the progress of geopolymerization reaction and consequently decreases compressive strength.",
journal = "Science of Sintering",
title = "Physico-chemical and mechanical properties of geopolymer/zircon composites",
volume = "54",
number = "1",
pages = "11-24",
doi = "10.2298/SOS2201011K"
}

Kljajević, L. M., Nenadović, M., Petković, M., Bučevac, D., Pavlović, V. B., Mladenović-Nikolić, N.,& Nenadović, S. B.. (2022). Physico-chemical and mechanical properties of geopolymer/zircon composites. in Science of Sintering, 54(1), 11-24.
https://doi.org/10.2298/SOS2201011K

Kljajević LM, Nenadović M, Petković M, Bučevac D, Pavlović VB, Mladenović-Nikolić N, Nenadović SB. Physico-chemical and mechanical properties of geopolymer/zircon composites. in Science of Sintering. 2022;54(1):11-24.
doi:10.2298/SOS2201011K .

Kljajević, Ljiljana M., Nenadović, Miloš, Petković, Marijana, Bučevac, Dušan, Pavlović, Vladimir B., Mladenović-Nikolić, Nataša, Nenadović, Snežana B., "Physico-chemical and mechanical properties of geopolymer/zircon composites" in Science of Sintering, 54, no. 1 (2022):11-24,
https://doi.org/10.2298/SOS2201011K . .

TY  - JOUR
AU  - Vukanac, Ivana
AU  - Šešlak, Bojan Ž.
AU  - Kandić, Aleksandar
AU  - Čeliković, Igor T.
AU  - Mladenović-Nikolić, Nataša
AU  - Milanović, Tamara J.
AU  - Obradović, Zorica
AU  - Đurašević, Mirjana M.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10096
AB  - In order to compare alpha-particle and gamma-ray spectrometry, the activity concentrations of 235U, 238U and 226Ra in samples of coal, slag and fly-ash from the thermal power plant “Nikola Tesla A”, Serbia, were determined by these two methods. Methods were compared and discussed from the point of view of its precision, difficulty to apply and complexity. Gamma-ray spectrometry was performed with HPGe (High Purity Germanium) spectrometer, while alpha activity was measured by PIPS (Passivated Implanted Planar Silicon) detector. For the alpha-particle spectrometry, the chemical procedures applied were chromatographic resin extraction for uranium isotopes and micro-coprecipitation for 226Ra. Thin alpha sources were prepared by electrodeposition and filtration through polypropylene membrane filter for uranium determination, while filtration technique was performed for radium sources. For the evaluation of the statistical difference between individual measurement results obtained by application of two methods Z - test was used. In order to evaluate the difference between two methods used, paired samples t-test and F-test were applied. Results show that there is no statistical difference between two methods used and that gamma-ray spectrometry is a valid alternative to time consuming alpha spectrometry.
T2  - Radiation Physics and Chemistry
T1  - A comparison of alpha-particle and gamma-ray spectrometry methods for determination of 235U, 238U and 226Ra activity concentration in samples of coal, slag and fly-ash
VL  - 193
SP  - 109933
DO  - 10.1016/j.radphyschem.2021.109933
ER  - 

@article{
author = "Vukanac, Ivana and Šešlak, Bojan Ž. and Kandić, Aleksandar and Čeliković, Igor T. and Mladenović-Nikolić, Nataša and Milanović, Tamara J. and Obradović, Zorica and Đurašević, Mirjana M.",
year = "2022",
abstract = "In order to compare alpha-particle and gamma-ray spectrometry, the activity concentrations of 235U, 238U and 226Ra in samples of coal, slag and fly-ash from the thermal power plant “Nikola Tesla A”, Serbia, were determined by these two methods. Methods were compared and discussed from the point of view of its precision, difficulty to apply and complexity. Gamma-ray spectrometry was performed with HPGe (High Purity Germanium) spectrometer, while alpha activity was measured by PIPS (Passivated Implanted Planar Silicon) detector. For the alpha-particle spectrometry, the chemical procedures applied were chromatographic resin extraction for uranium isotopes and micro-coprecipitation for 226Ra. Thin alpha sources were prepared by electrodeposition and filtration through polypropylene membrane filter for uranium determination, while filtration technique was performed for radium sources. For the evaluation of the statistical difference between individual measurement results obtained by application of two methods Z - test was used. In order to evaluate the difference between two methods used, paired samples t-test and F-test were applied. Results show that there is no statistical difference between two methods used and that gamma-ray spectrometry is a valid alternative to time consuming alpha spectrometry.",
journal = "Radiation Physics and Chemistry",
title = "A comparison of alpha-particle and gamma-ray spectrometry methods for determination of 235U, 238U and 226Ra activity concentration in samples of coal, slag and fly-ash",
volume = "193",
pages = "109933",
doi = "10.1016/j.radphyschem.2021.109933"
}

Vukanac, I., Šešlak, B. Ž., Kandić, A., Čeliković, I. T., Mladenović-Nikolić, N., Milanović, T. J., Obradović, Z.,& Đurašević, M. M.. (2022). A comparison of alpha-particle and gamma-ray spectrometry methods for determination of 235U, 238U and 226Ra activity concentration in samples of coal, slag and fly-ash. in Radiation Physics and Chemistry, 193, 109933.
https://doi.org/10.1016/j.radphyschem.2021.109933

Vukanac I, Šešlak BŽ, Kandić A, Čeliković IT, Mladenović-Nikolić N, Milanović TJ, Obradović Z, Đurašević MM. A comparison of alpha-particle and gamma-ray spectrometry methods for determination of 235U, 238U and 226Ra activity concentration in samples of coal, slag and fly-ash. in Radiation Physics and Chemistry. 2022;193:109933.
doi:10.1016/j.radphyschem.2021.109933 .

Vukanac, Ivana, Šešlak, Bojan Ž., Kandić, Aleksandar, Čeliković, Igor T., Mladenović-Nikolić, Nataša, Milanović, Tamara J., Obradović, Zorica, Đurašević, Mirjana M., "A comparison of alpha-particle and gamma-ray spectrometry methods for determination of 235U, 238U and 226Ra activity concentration in samples of coal, slag and fly-ash" in Radiation Physics and Chemistry, 193 (2022):109933,
https://doi.org/10.1016/j.radphyschem.2021.109933 . .

TY  - CONF
AU  - Đurašević, Mirjana M.
AU  - Kandić, Aleksandar
AU  - Vukanac, Ivana
AU  - Čeliković, Igor T.
AU  - Mladenović-Nikolić, Nataša
AU  - Milanović, Tamara J.
AU  - Obradović, Zorica
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10011
AB  - Da bi se postigla tačnost i preciznost dobijenih rezultata pri gamaspektrometrijskom merenju uzoraka iz životne sredine neophodno je obezbediti odgovarajuće kalibracione standarde. Imajući u vidu da i sami standardi vremenom gube na kvalitetu zbog degradacije matriksa, od izuzetne je važnosti praćenje stabilnosti standarda koji se koriste. U ovom radu prikazani su rezultati ispitivanja karakteristika krivih efikasnosti u odnosu na starenje matriksa. Napravljeni su radni kalibracioni standardi sa tri različita matriksa (aktivni ugalj, zemlja i pesak), upakovani u cilindričnu geometriju kutijice od 120 ml i 250 ml i mereni na poluprovodničkom HPGe detektoru. Isti standardi ponovo su mereni nakon četiri godine u kontakt geometriji u odnosu na detektor i izvrnuto sa poklopcem kutijice ka detektoru. Analiza dobijenih rezultata pokazala je odstupanja u vrednostima efikasnosti, što ukazuje na degradaciju svih standarda u smislu narušavanja njihove homogenosti. Takvi standardi se ne mogu smatrati pouzdanim za korišćenje.
AB  - The gammaspectrometric measurement of the environmental samples requires the use of appropriate calibration standards in order to achieve the accuracy and precision of the obtained results. Taking into account that the standards lose their quality over time due to the degradation of the matrix, it is extremely important to keep tracking their stability. Comprehensive reconsideration on efficiency curves with respect to the ageing of calibration standards is presented in this paper. Spiked laboratory standards of different matrices (active coal, soil and sand) were prepared in two measurement geometries, PVC cylindrical 120 ml and 250 ml boxes. The same standards were measured after four years in contact geometry on the detector and upside down (box cover towards the detector). The analysis of the obtained results showed discrepancies in efficiency values and it indicates that the homogeneity of standards is disturbed. Such standards are not reliable for use.
PB  - Institut za nuklearne nauke "Vinča"
PB  - Društvo za zaštitu od zračenja Srbije i Crne Gore
C3  - 31. симпозијум ДЗЗСЦГ : зборник радова
T1  - Dugovremenska stabilnost kalibracionih standarda različitih matriksa u gamaspektrometriji
T1  - On the Long-Term Stability of the Calibration Standards in Different Matrices for Gamma-Ray Spectrometry
SP  - 181
EP  - 186
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10011
ER  - 

@conference{
author = "Đurašević, Mirjana M. and Kandić, Aleksandar and Vukanac, Ivana and Čeliković, Igor T. and Mladenović-Nikolić, Nataša and Milanović, Tamara J. and Obradović, Zorica",
year = "2021",
abstract = "Da bi se postigla tačnost i preciznost dobijenih rezultata pri gamaspektrometrijskom merenju uzoraka iz životne sredine neophodno je obezbediti odgovarajuće kalibracione standarde. Imajući u vidu da i sami standardi vremenom gube na kvalitetu zbog degradacije matriksa, od izuzetne je važnosti praćenje stabilnosti standarda koji se koriste. U ovom radu prikazani su rezultati ispitivanja karakteristika krivih efikasnosti u odnosu na starenje matriksa. Napravljeni su radni kalibracioni standardi sa tri različita matriksa (aktivni ugalj, zemlja i pesak), upakovani u cilindričnu geometriju kutijice od 120 ml i 250 ml i mereni na poluprovodničkom HPGe detektoru. Isti standardi ponovo su mereni nakon četiri godine u kontakt geometriji u odnosu na detektor i izvrnuto sa poklopcem kutijice ka detektoru. Analiza dobijenih rezultata pokazala je odstupanja u vrednostima efikasnosti, što ukazuje na degradaciju svih standarda u smislu narušavanja njihove homogenosti. Takvi standardi se ne mogu smatrati pouzdanim za korišćenje., The gammaspectrometric measurement of the environmental samples requires the use of appropriate calibration standards in order to achieve the accuracy and precision of the obtained results. Taking into account that the standards lose their quality over time due to the degradation of the matrix, it is extremely important to keep tracking their stability. Comprehensive reconsideration on efficiency curves with respect to the ageing of calibration standards is presented in this paper. Spiked laboratory standards of different matrices (active coal, soil and sand) were prepared in two measurement geometries, PVC cylindrical 120 ml and 250 ml boxes. The same standards were measured after four years in contact geometry on the detector and upside down (box cover towards the detector). The analysis of the obtained results showed discrepancies in efficiency values and it indicates that the homogeneity of standards is disturbed. Such standards are not reliable for use.",
publisher = "Institut za nuklearne nauke "Vinča", Društvo za zaštitu od zračenja Srbije i Crne Gore",
journal = "31. симпозијум ДЗЗСЦГ : зборник радова",
title = "Dugovremenska stabilnost kalibracionih standarda različitih matriksa u gamaspektrometriji, On the Long-Term Stability of the Calibration Standards in Different Matrices for Gamma-Ray Spectrometry",
pages = "181-186",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10011"
}

Đurašević, M. M., Kandić, A., Vukanac, I., Čeliković, I. T., Mladenović-Nikolić, N., Milanović, T. J.,& Obradović, Z.. (2021). Dugovremenska stabilnost kalibracionih standarda različitih matriksa u gamaspektrometriji. in 31. симпозијум ДЗЗСЦГ : зборник радова
Institut za nuklearne nauke "Vinča"., 181-186.
https://hdl.handle.net/21.15107/rcub_vinar_10011

Đurašević MM, Kandić A, Vukanac I, Čeliković IT, Mladenović-Nikolić N, Milanović TJ, Obradović Z. Dugovremenska stabilnost kalibracionih standarda različitih matriksa u gamaspektrometriji. in 31. симпозијум ДЗЗСЦГ : зборник радова. 2021;:181-186.
https://hdl.handle.net/21.15107/rcub_vinar_10011 .

Đurašević, Mirjana M., Kandić, Aleksandar, Vukanac, Ivana, Čeliković, Igor T., Mladenović-Nikolić, Nataša, Milanović, Tamara J., Obradović, Zorica, "Dugovremenska stabilnost kalibracionih standarda različitih matriksa u gamaspektrometriji" in 31. симпозијум ДЗЗСЦГ : зборник радова (2021):181-186,
https://hdl.handle.net/21.15107/rcub_vinar_10011 .

TY  - JOUR
AU  - Mladenović, Nataša
AU  - Kljajević, Ljiljana M.
AU  - Nenadović, Snežana S.
AU  - Ivanović, Marija M.
AU  - Čalija, Bojan
AU  - Gulicovski, Jelena J.
AU  - Trivunac, Katarina V.
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8561
AB  - Fundamental research of inorganic polymers prepared from available aluminosilicate precursors represent an innovative class of materials characterized by low energy consumption for production. This is just one of the reasons why their use is focused in protecting the environment for removing of heavy metals from aqueous solutions. The concentration of hydroxide as activator solution plays an important role in the geopolymerization process. The present study examined the use of geopolymer materials, obtained in reaction of geopolymerizations of metakaolin as precursor activated with NaOH concentration 2.0, 4.0, 6.0 and 8.0 mol/dm3 for removal of cadmium ions from aqueous solutions. The structure and properties of the obtained geopolymer samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflection infrared spectroscopy (DRIFTS). To investigate the surface charge of geopolymers the zeta potential measurements were performed. Batch adsorption experiments conducted at room temperature (23 ± 1 °C) showed that the adsorption pattern followed the Freundlich isotherm model. The maximum removal of cadmium obtained from batch studies was 84.1% for GP6M at pH ≈ 6.7. The results generally showed that geopolymer samples could be considered as a potential adsorbent for cadmium removal from aqueous solutions. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
T2  - Journal of Inorganic and Organometallic Polymers and Materials
T1  - The Applications of New Inorganic Polymer for Adsorption Cadmium from Waste Water
VL  - 30
IS  - 2
SP  - 554
EP  - 563
DO  - 10.1007/s10904-019-01215-y
ER  - 

@article{
author = "Mladenović, Nataša and Kljajević, Ljiljana M. and Nenadović, Snežana S. and Ivanović, Marija M. and Čalija, Bojan and Gulicovski, Jelena J. and Trivunac, Katarina V.",
year = "2020",
abstract = "Fundamental research of inorganic polymers prepared from available aluminosilicate precursors represent an innovative class of materials characterized by low energy consumption for production. This is just one of the reasons why their use is focused in protecting the environment for removing of heavy metals from aqueous solutions. The concentration of hydroxide as activator solution plays an important role in the geopolymerization process. The present study examined the use of geopolymer materials, obtained in reaction of geopolymerizations of metakaolin as precursor activated with NaOH concentration 2.0, 4.0, 6.0 and 8.0 mol/dm3 for removal of cadmium ions from aqueous solutions. The structure and properties of the obtained geopolymer samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflection infrared spectroscopy (DRIFTS). To investigate the surface charge of geopolymers the zeta potential measurements were performed. Batch adsorption experiments conducted at room temperature (23 ± 1 °C) showed that the adsorption pattern followed the Freundlich isotherm model. The maximum removal of cadmium obtained from batch studies was 84.1% for GP6M at pH ≈ 6.7. The results generally showed that geopolymer samples could be considered as a potential adsorbent for cadmium removal from aqueous solutions. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.",
journal = "Journal of Inorganic and Organometallic Polymers and Materials",
title = "The Applications of New Inorganic Polymer for Adsorption Cadmium from Waste Water",
volume = "30",
number = "2",
pages = "554-563",
doi = "10.1007/s10904-019-01215-y"
}

Mladenović, N., Kljajević, L. M., Nenadović, S. S., Ivanović, M. M., Čalija, B., Gulicovski, J. J.,& Trivunac, K. V.. (2020). The Applications of New Inorganic Polymer for Adsorption Cadmium from Waste Water. in Journal of Inorganic and Organometallic Polymers and Materials, 30(2), 554-563.
https://doi.org/10.1007/s10904-019-01215-y

Mladenović N, Kljajević LM, Nenadović SS, Ivanović MM, Čalija B, Gulicovski JJ, Trivunac KV. The Applications of New Inorganic Polymer for Adsorption Cadmium from Waste Water. in Journal of Inorganic and Organometallic Polymers and Materials. 2020;30(2):554-563.
doi:10.1007/s10904-019-01215-y .

Mladenović, Nataša, Kljajević, Ljiljana M., Nenadović, Snežana S., Ivanović, Marija M., Čalija, Bojan, Gulicovski, Jelena J., Trivunac, Katarina V., "The Applications of New Inorganic Polymer for Adsorption Cadmium from Waste Water" in Journal of Inorganic and Organometallic Polymers and Materials, 30, no. 2 (2020):554-563,
https://doi.org/10.1007/s10904-019-01215-y . .