TY  - CONF
AU  - Lukić, Ivana
AU  - Kesić, Željka
AU  - Zdujić, Miodrag
AU  - Skala, Dejan
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6934
AB  - Biodiesel, a mixture of fatty acid methyl esters (FAME), is an excellent non-toxic, and biodegradable substitute for mineral diesel fuels produced from crude oil. It is made from renewable sources by transesterification of triglycerides with methanol, or by a reaction usually defined as methanolysis. Usage of low-quality feedstock, such as waste cooking oil (WCO), is challenging due to the undesirable side reactions as a result of the presence of free fatty acids (FFA), and water, thus a pretreatment stage before subjecting it to the transesterification process is usually required. In the present study, a two-step approach based on an adsorptive pretreatment with quicklime in order to remove FFA from WCO, followed by methanolysis using CaO∙ZnO as a heterogeneous catalyst was proposed. The first step was analyzed with the goal to define the optimal temperature of adsorption, the adsorbent particle size, calcination procedure, as well as the necessary amount of quicklime used. The analysis of adsorption kinetics was performed using pseudo-first and pseudo-second order kinetic models, and the efficiency of quicklime in the FFA removal from the WCO was also determined. The results showed that FFA from WCO could be successfully removed using quicklime as adsorbent at 30 °C for 1 h, with a removal efficiency of 72% and an adsorption capacity of 910 mg/g. The amount of Ca2+ ion present in the oil after the pretreatment was determined to be 12.64 mg/kg, showing that a very small amount of calcium from CaO was dissolved in treated WCO. The FTIR analysis of quicklime after the adsorption of FFA confirmed the interaction of the carboxyl group in FFA with the active site of the adsorbent. Adsorptive pretreatment had a positive effect on the rate of transesterification reaction with CaO∙ZnO as a catalyst, enabling the achievement of over 96% of FAME yield in only 15 min at 60 °C. The present study showed that quicklime, being cheap, available, and efficient, has considerable potential for the removal of FFA from the WCO. Besides, both the adsorption and the heterogeneously catalyzed methanolysis are environmentally and economically acceptable processes.
PB  - Valladolid : The lnstitute of Bioeconomy of University of Valladolid
C3  - Book of abstracts / 2nd Greenering International Conference, 21–23th March 2023, Valladolid, Spain
T1  - Adsorptive pretreatment of waste cooking oil using quicklime for two-step biodiesel production
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6934
ER  - 

@conference{
author = "Lukić, Ivana and Kesić, Željka and Zdujić, Miodrag and Skala, Dejan",
year = "2023",
abstract = "Biodiesel, a mixture of fatty acid methyl esters (FAME), is an excellent non-toxic, and biodegradable substitute for mineral diesel fuels produced from crude oil. It is made from renewable sources by transesterification of triglycerides with methanol, or by a reaction usually defined as methanolysis. Usage of low-quality feedstock, such as waste cooking oil (WCO), is challenging due to the undesirable side reactions as a result of the presence of free fatty acids (FFA), and water, thus a pretreatment stage before subjecting it to the transesterification process is usually required. In the present study, a two-step approach based on an adsorptive pretreatment with quicklime in order to remove FFA from WCO, followed by methanolysis using CaO∙ZnO as a heterogeneous catalyst was proposed. The first step was analyzed with the goal to define the optimal temperature of adsorption, the adsorbent particle size, calcination procedure, as well as the necessary amount of quicklime used. The analysis of adsorption kinetics was performed using pseudo-first and pseudo-second order kinetic models, and the efficiency of quicklime in the FFA removal from the WCO was also determined. The results showed that FFA from WCO could be successfully removed using quicklime as adsorbent at 30 °C for 1 h, with a removal efficiency of 72% and an adsorption capacity of 910 mg/g. The amount of Ca2+ ion present in the oil after the pretreatment was determined to be 12.64 mg/kg, showing that a very small amount of calcium from CaO was dissolved in treated WCO. The FTIR analysis of quicklime after the adsorption of FFA confirmed the interaction of the carboxyl group in FFA with the active site of the adsorbent. Adsorptive pretreatment had a positive effect on the rate of transesterification reaction with CaO∙ZnO as a catalyst, enabling the achievement of over 96% of FAME yield in only 15 min at 60 °C. The present study showed that quicklime, being cheap, available, and efficient, has considerable potential for the removal of FFA from the WCO. Besides, both the adsorption and the heterogeneously catalyzed methanolysis are environmentally and economically acceptable processes.",
publisher = "Valladolid : The lnstitute of Bioeconomy of University of Valladolid",
journal = "Book of abstracts / 2nd Greenering International Conference, 21–23th March 2023, Valladolid, Spain",
title = "Adsorptive pretreatment of waste cooking oil using quicklime for two-step biodiesel production",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6934"
}

Lukić, I., Kesić, Ž., Zdujić, M.,& Skala, D.. (2023). Adsorptive pretreatment of waste cooking oil using quicklime for two-step biodiesel production. in Book of abstracts / 2nd Greenering International Conference, 21–23th March 2023, Valladolid, Spain
Valladolid : The lnstitute of Bioeconomy of University of Valladolid..
https://hdl.handle.net/21.15107/rcub_technorep_6934

Lukić I, Kesić Ž, Zdujić M, Skala D. Adsorptive pretreatment of waste cooking oil using quicklime for two-step biodiesel production. in Book of abstracts / 2nd Greenering International Conference, 21–23th March 2023, Valladolid, Spain. 2023;.
https://hdl.handle.net/21.15107/rcub_technorep_6934 .

Lukić, Ivana, Kesić, Željka, Zdujić, Miodrag, Skala, Dejan, "Adsorptive pretreatment of waste cooking oil using quicklime for two-step biodiesel production" in Book of abstracts / 2nd Greenering International Conference, 21–23th March 2023, Valladolid, Spain (2023),
https://hdl.handle.net/21.15107/rcub_technorep_6934 .

TY  - JOUR
AU  - Lukić, Ivana
AU  - Kesić, Željka
AU  - Zdujić, Miodrag
AU  - Skala, Dejan
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6569
AB  - Synthesis of biodiesel from various plant oils is realized by the transesterification of triglycerides with methanol or by a reaction usually defined as methanolysis. The usage of low-quality oils, such as waste cooking oil (WCO), is followed by undesirable side reactions as a result of the increased content of free fatty acids (FFA), and water. The presence of FFA in WCO usually requires a pretreatment stage before subjecting it to methanolysis. In the present work, heterogeneously catalyzed methanolysis of WCO with and without pretreatment was investigated. Removal of FFA from WCO was conducted by using only quicklime or with the addition of a small amount of methanol (FFA to methanol = 1:3 molar ratio). The obtained results showed that pretreatment of WCO with quicklime at 30 °C after 1 h reduces the FFA content by 72 %, while the adsorption capacity was determined to be 910 mg g-1. The adsorptive pretreatment, as a simple operation, using low-cost quicklime under mild conditions, had a positive effect on the transesterification rate with CaO∙ZnO as a catalyst, enabling the achievement of over 96 % of biodiesel yield in only 15 min, compared to 1 h without the pretreatment. Furthermore, pretreated WCO allows an increase in repeated catalyst use and overall savings in the necessary amount of catalyst. The present study showed that quicklime is an economic, environmental-friendly, and sustainable material for FFA removal from WCO.
PB  - Association of the Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Adsorptive pretreatment of waste cooking oil using quicklime for fatty acid methyl esters synthesis
EP  - 84
IS  - 1
SP  - 69
VL  - 77
DO  - 10.2298/HEMIND220628005L
ER  - 

@article{
author = "Lukić, Ivana and Kesić, Željka and Zdujić, Miodrag and Skala, Dejan",
year = "2023",
abstract = "Synthesis of biodiesel from various plant oils is realized by the transesterification of triglycerides with methanol or by a reaction usually defined as methanolysis. The usage of low-quality oils, such as waste cooking oil (WCO), is followed by undesirable side reactions as a result of the increased content of free fatty acids (FFA), and water. The presence of FFA in WCO usually requires a pretreatment stage before subjecting it to methanolysis. In the present work, heterogeneously catalyzed methanolysis of WCO with and without pretreatment was investigated. Removal of FFA from WCO was conducted by using only quicklime or with the addition of a small amount of methanol (FFA to methanol = 1:3 molar ratio). The obtained results showed that pretreatment of WCO with quicklime at 30 °C after 1 h reduces the FFA content by 72 %, while the adsorption capacity was determined to be 910 mg g-1. The adsorptive pretreatment, as a simple operation, using low-cost quicklime under mild conditions, had a positive effect on the transesterification rate with CaO∙ZnO as a catalyst, enabling the achievement of over 96 % of biodiesel yield in only 15 min, compared to 1 h without the pretreatment. Furthermore, pretreated WCO allows an increase in repeated catalyst use and overall savings in the necessary amount of catalyst. The present study showed that quicklime is an economic, environmental-friendly, and sustainable material for FFA removal from WCO.",
publisher = "Association of the Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Adsorptive pretreatment of waste cooking oil using quicklime for fatty acid methyl esters synthesis",
pages = "84-69",
number = "1",
volume = "77",
doi = "10.2298/HEMIND220628005L"
}

Lukić, I., Kesić, Ž., Zdujić, M.,& Skala, D.. (2023). Adsorptive pretreatment of waste cooking oil using quicklime for fatty acid methyl esters synthesis. in Hemijska industrija
Association of the Chemical Engineers of Serbia., 77(1), 69-84.
https://doi.org/10.2298/HEMIND220628005L

Lukić I, Kesić Ž, Zdujić M, Skala D. Adsorptive pretreatment of waste cooking oil using quicklime for fatty acid methyl esters synthesis. in Hemijska industrija. 2023;77(1):69-84.
doi:10.2298/HEMIND220628005L .

Lukić, Ivana, Kesić, Željka, Zdujić, Miodrag, Skala, Dejan, "Adsorptive pretreatment of waste cooking oil using quicklime for fatty acid methyl esters synthesis" in Hemijska industrija, 77, no. 1 (2023):69-84,
https://doi.org/10.2298/HEMIND220628005L . .

TY  - JOUR
AU  - Poleti, Dejan
AU  - Karanović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5720
AB  - Powder mixtures of α-Bi2O3 containing 2, 5 and 10 mole % of TiO2, ZrO2 or HfO2 were homogenized, heated at 820ºC for 24 h and quenched in air. X-ray powder diffraction technique was used to characterize the prepared samples. In all cases metastable Bi2O3 polymorphs, γ-Bi2O3 or β-Bi2O3, are found as single or major phases. Addition of Ti4+ ions stabilizes γ-Bi2O3 polymorph, while either Zr4+ or Hf4+ ions stabilize β-Bi2O3 polymorph. In the samples with 2 and 5 mole % of TiO2 the presence of even two γ-Bi2O3 phases (Bi12TiO20 compound and a very low Ti-doped γ-Bi2O3) was established. Similarly, in the sample with 2 mole % of HfO2 two β-Bi2O3 phases were found. Phase composition of prepared samples, values of unit cell parameters and the appearance of two polymorphs with identical crystal structure but different unit cell parameters are discussed and compared with known data.
PB  - Belgrade : Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Phase composition of Bi2O3 specimens doped with Ti, Zr and Hf
EP  - 1096
IS  - 8
SP  - 1091
VL  - 77
DO  - 10.2298/JSC110914215P
UR  - https://hdl.handle.net/21.15107/rcub_dais_270
ER  - 

@article{
author = "Poleti, Dejan and Karanović, Ljiljana and Zdujić, Miodrag and Jovalekić, Čedomir",
year = "2012",
abstract = "Powder mixtures of α-Bi2O3 containing 2, 5 and 10 mole % of TiO2, ZrO2 or HfO2 were homogenized, heated at 820ºC for 24 h and quenched in air. X-ray powder diffraction technique was used to characterize the prepared samples. In all cases metastable Bi2O3 polymorphs, γ-Bi2O3 or β-Bi2O3, are found as single or major phases. Addition of Ti4+ ions stabilizes γ-Bi2O3 polymorph, while either Zr4+ or Hf4+ ions stabilize β-Bi2O3 polymorph. In the samples with 2 and 5 mole % of TiO2 the presence of even two γ-Bi2O3 phases (Bi12TiO20 compound and a very low Ti-doped γ-Bi2O3) was established. Similarly, in the sample with 2 mole % of HfO2 two β-Bi2O3 phases were found. Phase composition of prepared samples, values of unit cell parameters and the appearance of two polymorphs with identical crystal structure but different unit cell parameters are discussed and compared with known data.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Phase composition of Bi2O3 specimens doped with Ti, Zr and Hf",
pages = "1096-1091",
number = "8",
volume = "77",
doi = "10.2298/JSC110914215P",
url = "https://hdl.handle.net/21.15107/rcub_dais_270"
}

Poleti, D., Karanović, L., Zdujić, M.,& Jovalekić, Č.. (2012). Phase composition of Bi2O3 specimens doped with Ti, Zr and Hf. in Journal of the Serbian Chemical Society
Belgrade : Serbian Chemical Society., 77(8), 1091-1096.
https://doi.org/10.2298/JSC110914215P
https://hdl.handle.net/21.15107/rcub_dais_270

Poleti D, Karanović L, Zdujić M, Jovalekić Č. Phase composition of Bi2O3 specimens doped with Ti, Zr and Hf. in Journal of the Serbian Chemical Society. 2012;77(8):1091-1096.
doi:10.2298/JSC110914215P
https://hdl.handle.net/21.15107/rcub_dais_270 .

Poleti, Dejan, Karanović, Ljiljana, Zdujić, Miodrag, Jovalekić, Čedomir, "Phase composition of Bi2O3 specimens doped with Ti, Zr and Hf" in Journal of the Serbian Chemical Society, 77, no. 8 (2012):1091-1096,
https://doi.org/10.2298/JSC110914215P .,
https://hdl.handle.net/21.15107/rcub_dais_270 .

TY  - JOUR
AU  - Veljković, Ivana
AU  - Poleti, Dejan
AU  - Karanović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Branković, Goran
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5656
AB  - Extra phase-pure Li4Ti5O12 spinel with particle sizes less than 500 nm was synthesized by solid state reaction of mechanochemicaly activated mixture of nano anatase and Li2CO3 for a very short annealing time, 4 h at 800°C. Structural and microstructural properties, the mechanism of solid state reaction between anatase and Li2CO3 as well as thermal stability of prepared spinel were investigated using XRPD, SEM and TG/DSC analysis. The mechanism of reaction implies decomposition of Li2CO3 below 250ºC, formation of monoclinic Li2TiO3 as intermediate product between 400 and 600°C and its transformation to Li4Ti5O12 between 600-800ºC. The spinel structure is stable up to 1000ºC when it is decomposed due to Li2O evaporation.
PB  - Belgrade : International Institute for the Science of Sintering
T2  - Science of Sintering
T1  - Solid state synthesis of extra phase-pure Li4Ti5O12 spinel
EP  - 351
IS  - 3
SP  - 343
VL  - 43
DO  - 10.2298/SOS1103343V
UR  - https://hdl.handle.net/21.15107/rcub_dais_199
ER  - 

@article{
author = "Veljković, Ivana and Poleti, Dejan and Karanović, Ljiljana and Zdujić, Miodrag and Branković, Goran",
year = "2011",
abstract = "Extra phase-pure Li4Ti5O12 spinel with particle sizes less than 500 nm was synthesized by solid state reaction of mechanochemicaly activated mixture of nano anatase and Li2CO3 for a very short annealing time, 4 h at 800°C. Structural and microstructural properties, the mechanism of solid state reaction between anatase and Li2CO3 as well as thermal stability of prepared spinel were investigated using XRPD, SEM and TG/DSC analysis. The mechanism of reaction implies decomposition of Li2CO3 below 250ºC, formation of monoclinic Li2TiO3 as intermediate product between 400 and 600°C and its transformation to Li4Ti5O12 between 600-800ºC. The spinel structure is stable up to 1000ºC when it is decomposed due to Li2O evaporation.",
publisher = "Belgrade : International Institute for the Science of Sintering",
journal = "Science of Sintering",
title = "Solid state synthesis of extra phase-pure Li4Ti5O12 spinel",
pages = "351-343",
number = "3",
volume = "43",
doi = "10.2298/SOS1103343V",
url = "https://hdl.handle.net/21.15107/rcub_dais_199"
}

Veljković, I., Poleti, D., Karanović, L., Zdujić, M.,& Branković, G.. (2011). Solid state synthesis of extra phase-pure Li4Ti5O12 spinel. in Science of Sintering
Belgrade : International Institute for the Science of Sintering., 43(3), 343-351.
https://doi.org/10.2298/SOS1103343V
https://hdl.handle.net/21.15107/rcub_dais_199

Veljković I, Poleti D, Karanović L, Zdujić M, Branković G. Solid state synthesis of extra phase-pure Li4Ti5O12 spinel. in Science of Sintering. 2011;43(3):343-351.
doi:10.2298/SOS1103343V
https://hdl.handle.net/21.15107/rcub_dais_199 .

Veljković, Ivana, Poleti, Dejan, Karanović, Ljiljana, Zdujić, Miodrag, Branković, Goran, "Solid state synthesis of extra phase-pure Li4Ti5O12 spinel" in Science of Sintering, 43, no. 3 (2011):343-351,
https://doi.org/10.2298/SOS1103343V .,
https://hdl.handle.net/21.15107/rcub_dais_199 .

TY  - JOUR
AU  - Veljković, Ivana
AU  - Poleti, Dejan
AU  - Zdujić, Miodrag
AU  - Karanović, Ljiljana
AU  - Jovalekić, Čedomir
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5567
AB  - Nanocrystalline cubic titanium monoxide, TiOx (0.92 < x < 1.19), with mean crystallite size of ≈ 6 nm, was synthesized by mechanochemical treatment of Ti and TiO2 (rutile) powder mixtures with molar ratios of 1:1, 1.10:1 and 1.25:1. The mechanochemical solid state reaction in a high-energy planetary ball mill was completed for 2 h in either air or argon atmosphere. During heating in vacuum at 900 and 1000 °C for 24 h, nanocrystalline TiOx transforms to a well-crystallized, cubic or monoclinic TiOx. The materials prepared were characterized by XRPD, TGA/DSC and SEM/EDS analysis. © 2008 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Materials Letters
T1  - Mechanochemical synthesis of nanocrystalline titanium monoxide
EP  - 2771
IS  - 17-18
SP  - 2769
VL  - 62
DO  - 10.1016/j.matlet.2008.01.039
UR  - https://hdl.handle.net/21.15107/rcub_dais_3580
ER  - 

@article{
author = "Veljković, Ivana and Poleti, Dejan and Zdujić, Miodrag and Karanović, Ljiljana and Jovalekić, Čedomir",
year = "2008",
abstract = "Nanocrystalline cubic titanium monoxide, TiOx (0.92 < x < 1.19), with mean crystallite size of ≈ 6 nm, was synthesized by mechanochemical treatment of Ti and TiO2 (rutile) powder mixtures with molar ratios of 1:1, 1.10:1 and 1.25:1. The mechanochemical solid state reaction in a high-energy planetary ball mill was completed for 2 h in either air or argon atmosphere. During heating in vacuum at 900 and 1000 °C for 24 h, nanocrystalline TiOx transforms to a well-crystallized, cubic or monoclinic TiOx. The materials prepared were characterized by XRPD, TGA/DSC and SEM/EDS analysis. © 2008 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Materials Letters",
title = "Mechanochemical synthesis of nanocrystalline titanium monoxide",
pages = "2771-2769",
number = "17-18",
volume = "62",
doi = "10.1016/j.matlet.2008.01.039",
url = "https://hdl.handle.net/21.15107/rcub_dais_3580"
}

Veljković, I., Poleti, D., Zdujić, M., Karanović, L.,& Jovalekić, Č.. (2008). Mechanochemical synthesis of nanocrystalline titanium monoxide. in Materials Letters
Elsevier., 62(17-18), 2769-2771.
https://doi.org/10.1016/j.matlet.2008.01.039
https://hdl.handle.net/21.15107/rcub_dais_3580

Veljković I, Poleti D, Zdujić M, Karanović L, Jovalekić Č. Mechanochemical synthesis of nanocrystalline titanium monoxide. in Materials Letters. 2008;62(17-18):2769-2771.
doi:10.1016/j.matlet.2008.01.039
https://hdl.handle.net/21.15107/rcub_dais_3580 .

Veljković, Ivana, Poleti, Dejan, Zdujić, Miodrag, Karanović, Ljiljana, Jovalekić, Čedomir, "Mechanochemical synthesis of nanocrystalline titanium monoxide" in Materials Letters, 62, no. 17-18 (2008):2769-2771,
https://doi.org/10.1016/j.matlet.2008.01.039 .,
https://hdl.handle.net/21.15107/rcub_dais_3580 .

TY  - JOUR
AU  - Jovalekić, Čedomir
AU  - Zdujić, Miodrag
AU  - Poleti, Dejan
AU  - Karanović, Ljiljana
AU  - Mitrić, Miodrag
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5578
AB  - Powder mixtures of α-Bi2O3 (bismite) and monoclinic m-ZrO2 (baddeleyite) in the molar ratio 2:3 were mechanochemically and thermally treated with the goal to examine the phases, which may appear during such procedures. The prepared samples were characterized by X-ray powder diffraction, differential scanning calorimetry (DSC), electrical measurements, as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanochemical reaction leads to the gradual formation of a nanocrystalline phase, which resembles δ-Bi2O3, a high-temperature Bi2O3 polymorph. Isothermal sintering in air at a temperature of 820 °C for 24 h followed by quenching to room temperature yielded a mixture of ZrO2-stabilized β-Bi2O3 and m-ZrO2 phases, whereas in slowly cooled products, the complete separation of the initial α-Bi2O3 and m-ZrO2 constituents was observed. The dielectric permittivity of the sintered samples significantly depended on the temperature. The sintered and quenched samples exhibited a hysteresis dependence of the dielectric shift, showing that the ZrO2-doped β-Bi2O3 phase possess ferroelectric properties, which were detected for the first time. This fact, together with Rietveld refinement of the β-Bi2O3/m-ZrO2 mixture based on neutron powder diffraction data showed that ZrO2-doped β-Bi2O3 has a non-centrosymmetric structure with P over(4, -) 21 c as the true space group. The ZrO2 content in the doped β-Bi2O3 and the crystal chemical reasons for the stabilization of the β-Bi2O3 phase by the addition of m-ZrO2 are discussed. © 2008 Elsevier Inc. All rights reserved.
T2  - Journal of Solid State Chemistry
T1  - Structural and electrical properties of the 2Bi2O3·3ZrO2 system
EP  - 1329
IS  - 6
SP  - 1321
VL  - 181
DO  - 10.1016/j.jssc.2008.02.038
UR  - https://hdl.handle.net/21.15107/rcub_dais_3582
ER  - 

@article{
author = "Jovalekić, Čedomir and Zdujić, Miodrag and Poleti, Dejan and Karanović, Ljiljana and Mitrić, Miodrag",
year = "2008",
abstract = "Powder mixtures of α-Bi2O3 (bismite) and monoclinic m-ZrO2 (baddeleyite) in the molar ratio 2:3 were mechanochemically and thermally treated with the goal to examine the phases, which may appear during such procedures. The prepared samples were characterized by X-ray powder diffraction, differential scanning calorimetry (DSC), electrical measurements, as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanochemical reaction leads to the gradual formation of a nanocrystalline phase, which resembles δ-Bi2O3, a high-temperature Bi2O3 polymorph. Isothermal sintering in air at a temperature of 820 °C for 24 h followed by quenching to room temperature yielded a mixture of ZrO2-stabilized β-Bi2O3 and m-ZrO2 phases, whereas in slowly cooled products, the complete separation of the initial α-Bi2O3 and m-ZrO2 constituents was observed. The dielectric permittivity of the sintered samples significantly depended on the temperature. The sintered and quenched samples exhibited a hysteresis dependence of the dielectric shift, showing that the ZrO2-doped β-Bi2O3 phase possess ferroelectric properties, which were detected for the first time. This fact, together with Rietveld refinement of the β-Bi2O3/m-ZrO2 mixture based on neutron powder diffraction data showed that ZrO2-doped β-Bi2O3 has a non-centrosymmetric structure with P over(4, -) 21 c as the true space group. The ZrO2 content in the doped β-Bi2O3 and the crystal chemical reasons for the stabilization of the β-Bi2O3 phase by the addition of m-ZrO2 are discussed. © 2008 Elsevier Inc. All rights reserved.",
journal = "Journal of Solid State Chemistry",
title = "Structural and electrical properties of the 2Bi2O3·3ZrO2 system",
pages = "1329-1321",
number = "6",
volume = "181",
doi = "10.1016/j.jssc.2008.02.038",
url = "https://hdl.handle.net/21.15107/rcub_dais_3582"
}

Jovalekić, Č., Zdujić, M., Poleti, D., Karanović, L.,& Mitrić, M.. (2008). Structural and electrical properties of the 2Bi2O3·3ZrO2 system. in Journal of Solid State Chemistry, 181(6), 1321-1329.
https://doi.org/10.1016/j.jssc.2008.02.038
https://hdl.handle.net/21.15107/rcub_dais_3582

Jovalekić Č, Zdujić M, Poleti D, Karanović L, Mitrić M. Structural and electrical properties of the 2Bi2O3·3ZrO2 system. in Journal of Solid State Chemistry. 2008;181(6):1321-1329.
doi:10.1016/j.jssc.2008.02.038
https://hdl.handle.net/21.15107/rcub_dais_3582 .

Jovalekić, Čedomir, Zdujić, Miodrag, Poleti, Dejan, Karanović, Ljiljana, Mitrić, Miodrag, "Structural and electrical properties of the 2Bi2O3·3ZrO2 system" in Journal of Solid State Chemistry, 181, no. 6 (2008):1321-1329,
https://doi.org/10.1016/j.jssc.2008.02.038 .,
https://hdl.handle.net/21.15107/rcub_dais_3582 .