TY  - JOUR
AU  - Zdujić, Miodrag
AU  - Lukić, Ivana
AU  - Kesić, Željka
AU  - Janković-Častvan, Ivona
AU  - Marković, Smilja
AU  - Jovalekić, Čedomir
AU  - Skala, Dejan
PY  - 2019
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4261
AB  - The powder mixtures of calcium oxide (CaO) and silica gel (SiO2) in molar ratios of 1:1, 1.5:1, 2:1 and 3:1 were mechanochemically treated with the addition of water, and were subsequently calcined with a goal of synthesizing CaSiO3, Ca3Si2O7, Ca2SiO4 compounds and CaO/Ca2SiO4 two-phase mixture. The prepared materials were characterized by XRD, FTIR, SEM/EDS, particle size laser diffraction (PSLD), UV-vis diffuse reflectance spectroscopy (DRS), N-2 adsorption/desorption isotherms, Hammett indicator for basic strength and volumetric analysis for free CaO content. The catalytic activity of calcium silicates with different Ca/Si ratios was tested in the transesterification of triacylglycerols (sunflower oil) with methanol. Samples obtained with initial composition 2CaO center dot SiO2 and 3CaO center dot SiO2 calcined at 700 degrees C, and 3CaO center dot SiO2 calcined at 900 degrees C had high catalytic activity, resulting with triacylglycerols conversion and fatty acids methyl ester formation (FAME or biodiesel) above 96%. The activity of these samples can be attributed to the existence of free CaO defined by CaO/Ca2SiO4 complex mixture. The effect of different amount of catalyst used for transesterification (0.2-2 wt%) was analyzed using the most active catalyst i.e. 3CaO center dot SiO2 calcined at 700 degrees C as well as possibility of its reuse for biodiesel synthesis. It was also found that CaSiO3, Ca3Si2O7 and Ca2SiO4, phases did not possess catalytic activity.
PB  - Elsevier Science Bv, Amsterdam
T2  - Advanced Powder Technology
T1  - Synthesis of CaO-SiO2 compounds and their testing as heterogeneous catalysts for transesterification of sunflower oil
EP  - 1150
IS  - 6
SP  - 1141
VL  - 30
DO  - 10.1016/j.apt.2019.03.009
ER  - 

@article{
author = "Zdujić, Miodrag and Lukić, Ivana and Kesić, Željka and Janković-Častvan, Ivona and Marković, Smilja and Jovalekić, Čedomir and Skala, Dejan",
year = "2019",
abstract = "The powder mixtures of calcium oxide (CaO) and silica gel (SiO2) in molar ratios of 1:1, 1.5:1, 2:1 and 3:1 were mechanochemically treated with the addition of water, and were subsequently calcined with a goal of synthesizing CaSiO3, Ca3Si2O7, Ca2SiO4 compounds and CaO/Ca2SiO4 two-phase mixture. The prepared materials were characterized by XRD, FTIR, SEM/EDS, particle size laser diffraction (PSLD), UV-vis diffuse reflectance spectroscopy (DRS), N-2 adsorption/desorption isotherms, Hammett indicator for basic strength and volumetric analysis for free CaO content. The catalytic activity of calcium silicates with different Ca/Si ratios was tested in the transesterification of triacylglycerols (sunflower oil) with methanol. Samples obtained with initial composition 2CaO center dot SiO2 and 3CaO center dot SiO2 calcined at 700 degrees C, and 3CaO center dot SiO2 calcined at 900 degrees C had high catalytic activity, resulting with triacylglycerols conversion and fatty acids methyl ester formation (FAME or biodiesel) above 96%. The activity of these samples can be attributed to the existence of free CaO defined by CaO/Ca2SiO4 complex mixture. The effect of different amount of catalyst used for transesterification (0.2-2 wt%) was analyzed using the most active catalyst i.e. 3CaO center dot SiO2 calcined at 700 degrees C as well as possibility of its reuse for biodiesel synthesis. It was also found that CaSiO3, Ca3Si2O7 and Ca2SiO4, phases did not possess catalytic activity.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Advanced Powder Technology",
title = "Synthesis of CaO-SiO2 compounds and their testing as heterogeneous catalysts for transesterification of sunflower oil",
pages = "1150-1141",
number = "6",
volume = "30",
doi = "10.1016/j.apt.2019.03.009"
}

Zdujić, M., Lukić, I., Kesić, Ž., Janković-Častvan, I., Marković, S., Jovalekić, Č.,& Skala, D.. (2019). Synthesis of CaO-SiO2 compounds and their testing as heterogeneous catalysts for transesterification of sunflower oil. in Advanced Powder Technology
Elsevier Science Bv, Amsterdam., 30(6), 1141-1150.
https://doi.org/10.1016/j.apt.2019.03.009

Zdujić M, Lukić I, Kesić Ž, Janković-Častvan I, Marković S, Jovalekić Č, Skala D. Synthesis of CaO-SiO2 compounds and their testing as heterogeneous catalysts for transesterification of sunflower oil. in Advanced Powder Technology. 2019;30(6):1141-1150.
doi:10.1016/j.apt.2019.03.009 .

Zdujić, Miodrag, Lukić, Ivana, Kesić, Željka, Janković-Častvan, Ivona, Marković, Smilja, Jovalekić, Čedomir, Skala, Dejan, "Synthesis of CaO-SiO2 compounds and their testing as heterogeneous catalysts for transesterification of sunflower oil" in Advanced Powder Technology, 30, no. 6 (2019):1141-1150,
https://doi.org/10.1016/j.apt.2019.03.009 . .

TY  - JOUR
AU  - Kesić, Željka
AU  - Lukić, Ivana
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
AU  - Veljković, Vlada B.
AU  - Skala, Dejan
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3383
AB  - Calcium-containing perovskites CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 were synthesized by calcination of mechanochemically treated stoichiometric mixtures of CaCO3 and either TiO2, MnO2, ZrO2 or Fe2O3 powders. X-ray diffraction analysis revealed a pure single perovskite phase for all four samples after calcination. This study proved that the pure perovskite phase exhibited low or no catalytic activity at 60 degrees C for the methanolysis of sunflower oil. However, at 165 degrees C FAME yield of more than 90% was reached after 2 h using CaTiO3, CaMnO3 and CaZrO3 as catalyst. Contrary to inactive pure perovskites at 60 degrees C, the CaTiO3 and Ca2Fe2O5 samples containing a very small amount of "free" CaO also showed methanolysis activity at 60 degrees C. This fact can be used to explain some contradictory statements reported in literature related to the perovskites as catalyst for biodiesel synthesis at mild temperatures.
PB  - Elsevier Science Bv, Amsterdam
T2  - Fuel Processing Technology
T1  - Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis
EP  - 168
SP  - 162
VL  - 143
DO  - 10.1016/j.fuproc.2015.11.018
ER  - 

@article{
author = "Kesić, Željka and Lukić, Ivana and Zdujić, Miodrag and Jovalekić, Čedomir and Veljković, Vlada B. and Skala, Dejan",
year = "2016",
abstract = "Calcium-containing perovskites CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 were synthesized by calcination of mechanochemically treated stoichiometric mixtures of CaCO3 and either TiO2, MnO2, ZrO2 or Fe2O3 powders. X-ray diffraction analysis revealed a pure single perovskite phase for all four samples after calcination. This study proved that the pure perovskite phase exhibited low or no catalytic activity at 60 degrees C for the methanolysis of sunflower oil. However, at 165 degrees C FAME yield of more than 90% was reached after 2 h using CaTiO3, CaMnO3 and CaZrO3 as catalyst. Contrary to inactive pure perovskites at 60 degrees C, the CaTiO3 and Ca2Fe2O5 samples containing a very small amount of "free" CaO also showed methanolysis activity at 60 degrees C. This fact can be used to explain some contradictory statements reported in literature related to the perovskites as catalyst for biodiesel synthesis at mild temperatures.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Fuel Processing Technology",
title = "Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis",
pages = "168-162",
volume = "143",
doi = "10.1016/j.fuproc.2015.11.018"
}

Kesić, Ž., Lukić, I., Zdujić, M., Jovalekić, Č., Veljković, V. B.,& Skala, D.. (2016). Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis. in Fuel Processing Technology
Elsevier Science Bv, Amsterdam., 143, 162-168.
https://doi.org/10.1016/j.fuproc.2015.11.018

Kesić Ž, Lukić I, Zdujić M, Jovalekić Č, Veljković VB, Skala D. Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis. in Fuel Processing Technology. 2016;143:162-168.
doi:10.1016/j.fuproc.2015.11.018 .

Kesić, Željka, Lukić, Ivana, Zdujić, Miodrag, Jovalekić, Čedomir, Veljković, Vlada B., Skala, Dejan, "Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis" in Fuel Processing Technology, 143 (2016):162-168,
https://doi.org/10.1016/j.fuproc.2015.11.018 . .

TY  - JOUR
AU  - Kesić, Željka
AU  - Lukić, Ivana
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
AU  - Liu, Hui
AU  - Skala, Dejan
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2921
AB  - The goal of this study was to prepare a CaO·ZnO catalyst containing a small amount of K2CO3 and analyze its activity for biodiesel synthesis. The catalyst was prepared using the following procedure: CaO and ZnO (mole ratio of 1:2), water and K2CO3 (in various amounts) were mechanochemically treated and after milling heated at 700°C in air atmosphere for obtaining mixed CaO·ZnO/xK2CO3 oxides (x = 0, 1, 2 and 4 mol of K2CO3 per 10 mol of CaO). All the samples were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), scanning electron microscopy/ energy-dispersive spectroscopy (SEM/EDS), particle size laser diffraction (PSLD) distribution, solubility measurement of Ca, Zn and K ions in methanol as well as by determination of their alkalinity (Hammett indicator method). Prepared CaO·ZnO/xK2CO3 composite powders were tested as catalysts for methanolysis of sunflower oil at 70 °C using mole ratio of sunflower oil to methanol of 1:10 and with 2 mass% of catalyst based on oil weight. The presence of K2CO3 in prepared samples was found to increase the activity of catalyst, and that such effect is caused by homogeneous-heterogeneous catalysis of biodiesel synthesis.
AB  - Cilj ovih istraživanja bio je da se pripremi CaO·ZnO katalizator koji sadrži malu količinu K2CO3 i analizira njegova aktivnost u sintezi biodizela. Katalizator je pripremljen prema sledećoj proceduri: CaO i ZnO (molski odnos 1:2), voda i K2CO3 (u različitoj količini) su tretirani mehanohemijski i nakon mlevenja zagrevani na 700 °C u atmosferi vazduha da bi se dobila smeša oksida CaO·ZnO/xK2CO3 (x = 0, 1, 2 i 4 mol K2CO3 na 10 mol CaO). Karakterizacija pripremljenih katalizatora izvršena je metodama rendgenske difrakcije (XRD), indukovane kuplovane plazme (ICP), spektroskopije fotoelektrona dobijenih X-zracima (XPS), termogravimetrijske analize (TGA), infracrvene spektroskopije (FTIR), skenirajuće elektronske mikroskopije i energetske disperzione spektroskopije (SEM/EDS), raspodele veličine čestica (PSLD), merenjem rastvorljivosti katalizatora odnosno Ca, Zn i K jona u metanolu, kao i određivanjem njihove baznosti (metodom Hametovih indikatora). Pripremljeni CaO·ZnO/xK2CO3 kompozitni prahovi testirani su kao katalizatori u reakciji metanolize suncokretovog ulja na 70 °C, pri molarnom odnosu suncokretovog ulja i metanola od 1:10 i sa 2 mas.% katalizatora u odnosu na masu ulja. Pokazano je da prisustvo K2CO3 u pripremljenim uzorcima povećava aktivnost katalizatora i da je takav efekat posledica homogeno-heterogene katalize u sintezi biodizela.
PB  - Association of the Chemical Engineers of Serbia
T2  - Chemical Industry & Chemical Engineering Quarterly
T1  - Mechanochemical synthesis of CaO·ZnO.K2CO3 catalyst: Characterization and activity for methanolysis of sunflower oil
T1  - Mehanohemijska sinteza CaO·ZnO.K2CO3, katalizatora - karakterizacija i aktivnost u metanolizi suncokretovog ulja
EP  - 12
IS  - 1-1
SP  - 1
VL  - 21
DO  - 10.2298/CICEQ131026041K
ER  - 

@article{
author = "Kesić, Željka and Lukić, Ivana and Zdujić, Miodrag and Jovalekić, Čedomir and Liu, Hui and Skala, Dejan",
year = "2015",
abstract = "The goal of this study was to prepare a CaO·ZnO catalyst containing a small amount of K2CO3 and analyze its activity for biodiesel synthesis. The catalyst was prepared using the following procedure: CaO and ZnO (mole ratio of 1:2), water and K2CO3 (in various amounts) were mechanochemically treated and after milling heated at 700°C in air atmosphere for obtaining mixed CaO·ZnO/xK2CO3 oxides (x = 0, 1, 2 and 4 mol of K2CO3 per 10 mol of CaO). All the samples were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), scanning electron microscopy/ energy-dispersive spectroscopy (SEM/EDS), particle size laser diffraction (PSLD) distribution, solubility measurement of Ca, Zn and K ions in methanol as well as by determination of their alkalinity (Hammett indicator method). Prepared CaO·ZnO/xK2CO3 composite powders were tested as catalysts for methanolysis of sunflower oil at 70 °C using mole ratio of sunflower oil to methanol of 1:10 and with 2 mass% of catalyst based on oil weight. The presence of K2CO3 in prepared samples was found to increase the activity of catalyst, and that such effect is caused by homogeneous-heterogeneous catalysis of biodiesel synthesis., Cilj ovih istraživanja bio je da se pripremi CaO·ZnO katalizator koji sadrži malu količinu K2CO3 i analizira njegova aktivnost u sintezi biodizela. Katalizator je pripremljen prema sledećoj proceduri: CaO i ZnO (molski odnos 1:2), voda i K2CO3 (u različitoj količini) su tretirani mehanohemijski i nakon mlevenja zagrevani na 700 °C u atmosferi vazduha da bi se dobila smeša oksida CaO·ZnO/xK2CO3 (x = 0, 1, 2 i 4 mol K2CO3 na 10 mol CaO). Karakterizacija pripremljenih katalizatora izvršena je metodama rendgenske difrakcije (XRD), indukovane kuplovane plazme (ICP), spektroskopije fotoelektrona dobijenih X-zracima (XPS), termogravimetrijske analize (TGA), infracrvene spektroskopije (FTIR), skenirajuće elektronske mikroskopije i energetske disperzione spektroskopije (SEM/EDS), raspodele veličine čestica (PSLD), merenjem rastvorljivosti katalizatora odnosno Ca, Zn i K jona u metanolu, kao i određivanjem njihove baznosti (metodom Hametovih indikatora). Pripremljeni CaO·ZnO/xK2CO3 kompozitni prahovi testirani su kao katalizatori u reakciji metanolize suncokretovog ulja na 70 °C, pri molarnom odnosu suncokretovog ulja i metanola od 1:10 i sa 2 mas.% katalizatora u odnosu na masu ulja. Pokazano je da prisustvo K2CO3 u pripremljenim uzorcima povećava aktivnost katalizatora i da je takav efekat posledica homogeno-heterogene katalize u sintezi biodizela.",
publisher = "Association of the Chemical Engineers of Serbia",
journal = "Chemical Industry & Chemical Engineering Quarterly",
title = "Mechanochemical synthesis of CaO·ZnO.K2CO3 catalyst: Characterization and activity for methanolysis of sunflower oil, Mehanohemijska sinteza CaO·ZnO.K2CO3, katalizatora - karakterizacija i aktivnost u metanolizi suncokretovog ulja",
pages = "12-1",
number = "1-1",
volume = "21",
doi = "10.2298/CICEQ131026041K"
}

Kesić, Ž., Lukić, I., Zdujić, M., Jovalekić, Č., Liu, H.,& Skala, D.. (2015). Mechanochemical synthesis of CaO·ZnO.K2CO3 catalyst: Characterization and activity for methanolysis of sunflower oil. in Chemical Industry & Chemical Engineering Quarterly
Association of the Chemical Engineers of Serbia., 21(1-1), 1-12.
https://doi.org/10.2298/CICEQ131026041K

Kesić Ž, Lukić I, Zdujić M, Jovalekić Č, Liu H, Skala D. Mechanochemical synthesis of CaO·ZnO.K2CO3 catalyst: Characterization and activity for methanolysis of sunflower oil. in Chemical Industry & Chemical Engineering Quarterly. 2015;21(1-1):1-12.
doi:10.2298/CICEQ131026041K .

Kesić, Željka, Lukić, Ivana, Zdujić, Miodrag, Jovalekić, Čedomir, Liu, Hui, Skala, Dejan, "Mechanochemical synthesis of CaO·ZnO.K2CO3 catalyst: Characterization and activity for methanolysis of sunflower oil" in Chemical Industry & Chemical Engineering Quarterly, 21, no. 1-1 (2015):1-12,
https://doi.org/10.2298/CICEQ131026041K . .

TY  - JOUR
AU  - Zdujić, Miodrag
AU  - Poleti, Dejan
AU  - Jovalekić, Čedomir
AU  - Karanović, Ljiljana
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5532
AB  - A powder mixture of α-Bi2O3 and HfO2, in the molar ratio 2:3, was mechanochemically treated in a planetary ball mill under air, using zirconium oxide vials and balls as the milling medium. After 50 h of milling, the mechanochemical reaction led to the formation of a nanocrystalline δ-Bi2O3 phase (fluorite-type solid solution Bi0.78Hf0.59Zr0.63O3.61), with a crystallite size of 20 nm. The mechanochemical reaction started at a very beginning of milling accompanied by an accumulation of ZrO2 arising from the milling tools. The samples prepared after various milling times were characterized by X-ray powder diffraction and DSC analysis. The electrical properties of the as-milled and pressed Bi0.78Hf0.59Zr0.63O3.61 powder were studied using impedance spectroscopy in the temperature range from 100 to 700°C under air. The electrical conductivity was determined to be 9.43×10-6 and 0.080 S cm-1 for the temperatures of 300 and 700°C, respectively.
AB  - Smeša prahova α-Bi2O3 i HfO2 u molarnom odnosu 2:3 mehanohemijski je tretirana u planetarnom mlinu u atmosferi vazduha, koristeći cirkonijumske posude i kuglice kao medijum za mlevenje. Posle 50 h mlevenja, mehanohemijska reakcija dovodi do stvaranja nanokristalne δ-Bi2O3 faze (čvrsti rastvor fluoritske strukture Bi0,78Hf0,59Zr0,63O3,61), veličine kristalita 20 nm. Mehanohemijska reakcija otpočinje u samom početku mlevenja i praćena je akumulacijum ZrO2 koji potiče od medijuma za mlevenje. Uzorci dobijeni posle različitih vremena mlevenja karakterisani su rendgenskom strukturnom i termijskom analizom. Električna svojstva mlevenih i presovanih Bi0,78Hf0,59Zr0,63O3,61 prahova ispitivana su impedansnom spektroskopijom u temperaturnom opsegu od 100 do 700°C. Dobijena električna provodnost je 9,43·10-6 i 0,080 S cm-1 za temperaturu 300 i 700°C, redom.
PB  - Belgrade : Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2
EP  - 1411
IS  - 12
SP  - 1401
VL  - 74
DO  - 10.2298/JSC0912401Z
UR  - https://hdl.handle.net/21.15107/rcub_dais_174
ER  - 

@article{
author = "Zdujić, Miodrag and Poleti, Dejan and Jovalekić, Čedomir and Karanović, Ljiljana",
year = "2009",
abstract = "A powder mixture of α-Bi2O3 and HfO2, in the molar ratio 2:3, was mechanochemically treated in a planetary ball mill under air, using zirconium oxide vials and balls as the milling medium. After 50 h of milling, the mechanochemical reaction led to the formation of a nanocrystalline δ-Bi2O3 phase (fluorite-type solid solution Bi0.78Hf0.59Zr0.63O3.61), with a crystallite size of 20 nm. The mechanochemical reaction started at a very beginning of milling accompanied by an accumulation of ZrO2 arising from the milling tools. The samples prepared after various milling times were characterized by X-ray powder diffraction and DSC analysis. The electrical properties of the as-milled and pressed Bi0.78Hf0.59Zr0.63O3.61 powder were studied using impedance spectroscopy in the temperature range from 100 to 700°C under air. The electrical conductivity was determined to be 9.43×10-6 and 0.080 S cm-1 for the temperatures of 300 and 700°C, respectively., Smeša prahova α-Bi2O3 i HfO2 u molarnom odnosu 2:3 mehanohemijski je tretirana u planetarnom mlinu u atmosferi vazduha, koristeći cirkonijumske posude i kuglice kao medijum za mlevenje. Posle 50 h mlevenja, mehanohemijska reakcija dovodi do stvaranja nanokristalne δ-Bi2O3 faze (čvrsti rastvor fluoritske strukture Bi0,78Hf0,59Zr0,63O3,61), veličine kristalita 20 nm. Mehanohemijska reakcija otpočinje u samom početku mlevenja i praćena je akumulacijum ZrO2 koji potiče od medijuma za mlevenje. Uzorci dobijeni posle različitih vremena mlevenja karakterisani su rendgenskom strukturnom i termijskom analizom. Električna svojstva mlevenih i presovanih Bi0,78Hf0,59Zr0,63O3,61 prahova ispitivana su impedansnom spektroskopijom u temperaturnom opsegu od 100 do 700°C. Dobijena električna provodnost je 9,43·10-6 i 0,080 S cm-1 za temperaturu 300 i 700°C, redom.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2",
pages = "1411-1401",
number = "12",
volume = "74",
doi = "10.2298/JSC0912401Z",
url = "https://hdl.handle.net/21.15107/rcub_dais_174"
}

Zdujić, M., Poleti, D., Jovalekić, Č.,& Karanović, L.. (2009). Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2. in Journal of the Serbian Chemical Society
Belgrade : Serbian Chemical Society., 74(12), 1401-1411.
https://doi.org/10.2298/JSC0912401Z
https://hdl.handle.net/21.15107/rcub_dais_174

Zdujić M, Poleti D, Jovalekić Č, Karanović L. Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2. in Journal of the Serbian Chemical Society. 2009;74(12):1401-1411.
doi:10.2298/JSC0912401Z
https://hdl.handle.net/21.15107/rcub_dais_174 .

Zdujić, Miodrag, Poleti, Dejan, Jovalekić, Čedomir, Karanović, Ljiljana, "Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2" in Journal of the Serbian Chemical Society, 74, no. 12 (2009):1401-1411,
https://doi.org/10.2298/JSC0912401Z .,
https://hdl.handle.net/21.15107/rcub_dais_174 .

TY  - JOUR
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
AU  - Poleti, Dejan
AU  - Veljković, Ivana
AU  - Karanović, Ljiljana
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5533
AB  - Concurrent milling of Bi4Ti3O12 was carried out in a planetary ball mill with hardened-steel 13 or 6 mm diameter balls with a goal to investigate how the system responds to the constrains imposed by milling. Milling intensity for various milling parameters was derived from the electrical power measurement. The reverse amorphous ↔ crystalline phase transition induced by milling is governed by impact energy and frequency. Below a certain threshold value of impact energy crystallization does not occur, whereas a higher impact frequency accelerates amorphization. Mechanochemical reactions are predominantly discrete processes, which occur at the moment of impact. © 2009 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Materials Letters
T1  - Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound
EP  - 2544
IS  - 29
SP  - 2542
VL  - 63
DO  - 10.1016/j.matlet.2009.08.055
UR  - https://hdl.handle.net/21.15107/rcub_dais_3454
ER  - 

@article{
author = "Zdujić, Miodrag and Jovalekić, Čedomir and Poleti, Dejan and Veljković, Ivana and Karanović, Ljiljana",
year = "2009",
abstract = "Concurrent milling of Bi4Ti3O12 was carried out in a planetary ball mill with hardened-steel 13 or 6 mm diameter balls with a goal to investigate how the system responds to the constrains imposed by milling. Milling intensity for various milling parameters was derived from the electrical power measurement. The reverse amorphous ↔ crystalline phase transition induced by milling is governed by impact energy and frequency. Below a certain threshold value of impact energy crystallization does not occur, whereas a higher impact frequency accelerates amorphization. Mechanochemical reactions are predominantly discrete processes, which occur at the moment of impact. © 2009 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Materials Letters",
title = "Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound",
pages = "2544-2542",
number = "29",
volume = "63",
doi = "10.1016/j.matlet.2009.08.055",
url = "https://hdl.handle.net/21.15107/rcub_dais_3454"
}

Zdujić, M., Jovalekić, Č., Poleti, D., Veljković, I.,& Karanović, L.. (2009). Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound. in Materials Letters
Elsevier., 63(29), 2542-2544.
https://doi.org/10.1016/j.matlet.2009.08.055
https://hdl.handle.net/21.15107/rcub_dais_3454

Zdujić M, Jovalekić Č, Poleti D, Veljković I, Karanović L. Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound. in Materials Letters. 2009;63(29):2542-2544.
doi:10.1016/j.matlet.2009.08.055
https://hdl.handle.net/21.15107/rcub_dais_3454 .

Zdujić, Miodrag, Jovalekić, Čedomir, Poleti, Dejan, Veljković, Ivana, Karanović, Ljiljana, "Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound" in Materials Letters, 63, no. 29 (2009):2542-2544,
https://doi.org/10.1016/j.matlet.2009.08.055 .,
https://hdl.handle.net/21.15107/rcub_dais_3454 .

TY  - JOUR
AU  - Zdujić, Miodrag
AU  - Poleti, Dejan
AU  - Jovalekić, Čedomir
AU  - Karanović, Ljiljana
PY  - 2006
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5466
AB  - Concurrent mechanochemical treatment of either a stoichiometric 2Bi 2 O 3 · 3TiO 2 powder mixture or (pulverized) Bi 4 Ti 3 O 12 compound was performed in a planetary ball mill. Relevant structural parameters: crystallite size, amount of amorphous phase and the transformed fraction (as a result of chemical reaction between Bi 2 O 3 and TiO 2 ) of the powders milled for various milling times and intensities were derived from X-ray powder diffraction data. The obtained structural parameters were used to follow the kinetics of the reduction of crystallite size, amorphous phase formation and chemical reaction. In the powder mixture, during the early stage of mechanochemical treatment the Bi 2 (CO 3 )O 2 phase was found as an intermediate product which transformed into the highly amorphized Bi 4 Ti 3 O 12 phase as the milling progressed. On the other hand, mechanochemical treatment of Bi 4 Ti 3 O 12 powder induced a gradual deformation of the crystal lattice and destruction of the perovskite-type structure. However, in both cases, after a certain milling time, a very disordered, amorphous/nanocrystalline structure was obtained. It was demonstrated that in the steady state, the amorphous/nanocrystalline phase ratio depends on the milling conditions. Higher milling intensities induce 'nanocrystallization' of the amorphous phase, i.e., precipitation of crystallites with an average size below 20 nm. A kinetic model involving a nanocrystalline ↔ amorphous reaction, in which the forward and reverse reaction were first-order was postulated and used to analyze the formation of an amorphous phase.
PB  - Elsevier
T2  - Journal of Non-Crystalline Solids
T1  - The evolution of structure induced by intensive milling in the system 2Bi 2 O 3 · 3TiO 2
EP  - 3068
IS  - 28-29
SP  - 3058
VL  - 352
DO  - 10.1016/j.jnoncrysol.2006.03.072
ER  - 

@article{
author = "Zdujić, Miodrag and Poleti, Dejan and Jovalekić, Čedomir and Karanović, Ljiljana",
year = "2006",
abstract = "Concurrent mechanochemical treatment of either a stoichiometric 2Bi 2 O 3 · 3TiO 2 powder mixture or (pulverized) Bi 4 Ti 3 O 12 compound was performed in a planetary ball mill. Relevant structural parameters: crystallite size, amount of amorphous phase and the transformed fraction (as a result of chemical reaction between Bi 2 O 3 and TiO 2 ) of the powders milled for various milling times and intensities were derived from X-ray powder diffraction data. The obtained structural parameters were used to follow the kinetics of the reduction of crystallite size, amorphous phase formation and chemical reaction. In the powder mixture, during the early stage of mechanochemical treatment the Bi 2 (CO 3 )O 2 phase was found as an intermediate product which transformed into the highly amorphized Bi 4 Ti 3 O 12 phase as the milling progressed. On the other hand, mechanochemical treatment of Bi 4 Ti 3 O 12 powder induced a gradual deformation of the crystal lattice and destruction of the perovskite-type structure. However, in both cases, after a certain milling time, a very disordered, amorphous/nanocrystalline structure was obtained. It was demonstrated that in the steady state, the amorphous/nanocrystalline phase ratio depends on the milling conditions. Higher milling intensities induce 'nanocrystallization' of the amorphous phase, i.e., precipitation of crystallites with an average size below 20 nm. A kinetic model involving a nanocrystalline ↔ amorphous reaction, in which the forward and reverse reaction were first-order was postulated and used to analyze the formation of an amorphous phase.",
publisher = "Elsevier",
journal = "Journal of Non-Crystalline Solids",
title = "The evolution of structure induced by intensive milling in the system 2Bi 2 O 3 · 3TiO 2",
pages = "3068-3058",
number = "28-29",
volume = "352",
doi = "10.1016/j.jnoncrysol.2006.03.072"
}

Zdujić, M., Poleti, D., Jovalekić, Č.,& Karanović, L.. (2006). The evolution of structure induced by intensive milling in the system 2Bi 2 O 3 · 3TiO 2. in Journal of Non-Crystalline Solids
Elsevier., 352(28-29), 3058-3068.
https://doi.org/10.1016/j.jnoncrysol.2006.03.072

Zdujić M, Poleti D, Jovalekić Č, Karanović L. The evolution of structure induced by intensive milling in the system 2Bi 2 O 3 · 3TiO 2. in Journal of Non-Crystalline Solids. 2006;352(28-29):3058-3068.
doi:10.1016/j.jnoncrysol.2006.03.072 .

Zdujić, Miodrag, Poleti, Dejan, Jovalekić, Čedomir, Karanović, Ljiljana, "The evolution of structure induced by intensive milling in the system 2Bi 2 O 3 · 3TiO 2" in Journal of Non-Crystalline Solids, 352, no. 28-29 (2006):3058-3068,
https://doi.org/10.1016/j.jnoncrysol.2006.03.072 . .

TY  - JOUR
AU  - Poleti, Dejan
AU  - Karanović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
AU  - Branković, Zorica
PY  - 2004
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5416
AB  - A series of gamma-Bi2O3 phases doped with Zn, Si, Pb and Fe was prepared by mechanochemical treatment of corresponding oxide mixtures with a nominal composition 6Bi(2)O(3) (.) MOx (MOx = ZnO, SiO2, PbO) and 12Bi(2)O(3) (.) Fe2O3 using high-energy ball mill. The products are characterized by X-ray powder diffraction technique. Influence of milling conditions: milling time from 5 min to 10 h, milling medium (steel or ZrO2) and injected mechanical power on unit-cell parameters and crystallinity of products, as well as on reaction kinetics are investigated and discussed.
PB  - Amsterdam : Elsevier
T2  - Solid State Sciences
T1  - Mechanochemical synthesis of gamma-Bi2O3
EP  - 245
IS  - 3
SP  - 239
VL  - 6
DO  - 10.1016/j.solidstatesciences.2003.12.003
UR  - https://hdl.handle.net/21.15107/rcub_dais_12880
ER  - 

@article{
author = "Poleti, Dejan and Karanović, Ljiljana and Zdujić, Miodrag and Jovalekić, Čedomir and Branković, Zorica",
year = "2004",
abstract = "A series of gamma-Bi2O3 phases doped with Zn, Si, Pb and Fe was prepared by mechanochemical treatment of corresponding oxide mixtures with a nominal composition 6Bi(2)O(3) (.) MOx (MOx = ZnO, SiO2, PbO) and 12Bi(2)O(3) (.) Fe2O3 using high-energy ball mill. The products are characterized by X-ray powder diffraction technique. Influence of milling conditions: milling time from 5 min to 10 h, milling medium (steel or ZrO2) and injected mechanical power on unit-cell parameters and crystallinity of products, as well as on reaction kinetics are investigated and discussed.",
publisher = "Amsterdam : Elsevier",
journal = "Solid State Sciences",
title = "Mechanochemical synthesis of gamma-Bi2O3",
pages = "245-239",
number = "3",
volume = "6",
doi = "10.1016/j.solidstatesciences.2003.12.003",
url = "https://hdl.handle.net/21.15107/rcub_dais_12880"
}

Poleti, D., Karanović, L., Zdujić, M., Jovalekić, Č.,& Branković, Z.. (2004). Mechanochemical synthesis of gamma-Bi2O3. in Solid State Sciences
Amsterdam : Elsevier., 6(3), 239-245.
https://doi.org/10.1016/j.solidstatesciences.2003.12.003
https://hdl.handle.net/21.15107/rcub_dais_12880

Poleti D, Karanović L, Zdujić M, Jovalekić Č, Branković Z. Mechanochemical synthesis of gamma-Bi2O3. in Solid State Sciences. 2004;6(3):239-245.
doi:10.1016/j.solidstatesciences.2003.12.003
https://hdl.handle.net/21.15107/rcub_dais_12880 .

Poleti, Dejan, Karanović, Ljiljana, Zdujić, Miodrag, Jovalekić, Čedomir, Branković, Zorica, "Mechanochemical synthesis of gamma-Bi2O3" in Solid State Sciences, 6, no. 3 (2004):239-245,
https://doi.org/10.1016/j.solidstatesciences.2003.12.003 .,
https://hdl.handle.net/21.15107/rcub_dais_12880 .