TY  - JOUR
AU  - Nježić, Zvonko
AU  - Kostić, Milan D.
AU  - Marić, Boško D.
AU  - Stamenković, Olivera
AU  - Šimurina, Olivera D.
AU  - Krstić, Jugoslav
AU  - Veljković, Vlada B.
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5399
AB  - A low-cost, highly active CaO-based catalyst was prepared from waste filter cake (WFC) from a sugar beet processing factory by calcination in air at 900 °C for 2 h, referred to as the calcined filter cake (CFC). It was used to catalyze the rapeseed oil transesterification with methanol under mild reaction conditions (methanol-to-oil molar ratio of 9:1, catalyst loading of 4–10 %, and reaction temperature of 40–60 °C). Rapeseed oil was characterized regarding the physicochemical properties and fatty acid profile. Low free fatty acid content (about 2.0 mg KOH/g) allowed the direct use of the base CFC catalyst for rapeseed oil transesterification. Rapeseed oil has more unsaturated fatty acids (about 93 %), with oleic acid as the most abundant, than saturated fatty acids (about 7 %). A simplified model combining the changing mechanism of the reaction and the triacylglycerols mass transfer limitation successfully describes the kinetics of transesterification. A good agreement between the model and the experiment was proved by the mean relative percentage deviation for the conversion degree of only ± 7.43 % (based on 42 data). The apparent reaction rate constant follows the Arrhenius equation with the activation energy of 51.9 kJ mol−1. The FAME content higher than 96.5 % can be obtained in wide ranges of the catalyst amount (4–10 %) and the reaction time (about 45–70 min). The following conditions were optimum: the reaction temperature of 59.2 °C, the catalyst loading of 9.1 % (based on the oil weight), and the reaction time of 47 min.
PB  - Elsevier
T2  - Fuel
T1  - Kinetics and optimization of biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing plant
VL  - 334
SP  - 126581
DO  - 10.1016/j.fuel.2022.126581
ER  - 

@article{
author = "Nježić, Zvonko and Kostić, Milan D. and Marić, Boško D. and Stamenković, Olivera and Šimurina, Olivera D. and Krstić, Jugoslav and Veljković, Vlada B.",
year = "2023",
abstract = "A low-cost, highly active CaO-based catalyst was prepared from waste filter cake (WFC) from a sugar beet processing factory by calcination in air at 900 °C for 2 h, referred to as the calcined filter cake (CFC). It was used to catalyze the rapeseed oil transesterification with methanol under mild reaction conditions (methanol-to-oil molar ratio of 9:1, catalyst loading of 4–10 %, and reaction temperature of 40–60 °C). Rapeseed oil was characterized regarding the physicochemical properties and fatty acid profile. Low free fatty acid content (about 2.0 mg KOH/g) allowed the direct use of the base CFC catalyst for rapeseed oil transesterification. Rapeseed oil has more unsaturated fatty acids (about 93 %), with oleic acid as the most abundant, than saturated fatty acids (about 7 %). A simplified model combining the changing mechanism of the reaction and the triacylglycerols mass transfer limitation successfully describes the kinetics of transesterification. A good agreement between the model and the experiment was proved by the mean relative percentage deviation for the conversion degree of only ± 7.43 % (based on 42 data). The apparent reaction rate constant follows the Arrhenius equation with the activation energy of 51.9 kJ mol−1. The FAME content higher than 96.5 % can be obtained in wide ranges of the catalyst amount (4–10 %) and the reaction time (about 45–70 min). The following conditions were optimum: the reaction temperature of 59.2 °C, the catalyst loading of 9.1 % (based on the oil weight), and the reaction time of 47 min.",
publisher = "Elsevier",
journal = "Fuel",
title = "Kinetics and optimization of biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing plant",
volume = "334",
pages = "126581",
doi = "10.1016/j.fuel.2022.126581"
}

Nježić, Z., Kostić, M. D., Marić, B. D., Stamenković, O., Šimurina, O. D., Krstić, J.,& Veljković, V. B.. (2023). Kinetics and optimization of biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing plant. in Fuel
Elsevier., 334, 126581.
https://doi.org/10.1016/j.fuel.2022.126581

Nježić Z, Kostić MD, Marić BD, Stamenković O, Šimurina OD, Krstić J, Veljković VB. Kinetics and optimization of biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing plant. in Fuel. 2023;334:126581.
doi:10.1016/j.fuel.2022.126581 .

Nježić, Zvonko, Kostić, Milan D., Marić, Boško D., Stamenković, Olivera, Šimurina, Olivera D., Krstić, Jugoslav, Veljković, Vlada B., "Kinetics and optimization of biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing plant" in Fuel, 334 (2023):126581,
https://doi.org/10.1016/j.fuel.2022.126581 . .

TY  - JOUR
AU  - Miladinović, Marija
AU  - Pavlović, Stefan
AU  - Banković-Ilić, Ivana
AU  - Kostić, Milan
AU  - Stamenković, Olivera
AU  - Veljković, Vlada
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7206
AB  - Possibilities of using waste plum stones in biodiesel production were investigated. The plum kernels were used as a source to obtain oil by the Soxhlet extraction method, while the whole plum stones, the plum stone shells that remained after the crashing, and the plum kernel cake that remained after the oil extraction, were burned off to obtain ashes. The collected ashes were characterized by elemental composition, porosity, and base strength and tested for catalytic activity in transesterification of esterified plum kernel oil. Dominant elements were potassium, calcium, and magnesium at different contents in the three obtained ashes. The most active catalyst was the plum stone shell ash, so the effect of temperature (40, 50, and 60°C) on the reaction rate was investigated. The reaction rate constant increased with the reaction temperature with the activation energy value of 58.8 kJ mol-1. In addition, the plum stone shell ash can be reused as a catalyst after recalcination.
AB  - U ovom radu istraživana je mogućnost korišćenja otpadnih koštica šljive u proizvodnji biodizela. Jezgra  šljive su iskorišćena kao sirovina za dobijanje ulja primenom Soxhlet-ove metode ekstrakcije. Cele  koštice, ljuske koštica šljive i pogača dobijena nakon ekstrakcije ulja iz jezgra šljive spaljeni su da bi se  dobio pepeo, koji je korišćen kao katalizator. Dobijene tri vrste sakupljenog pepela su najpre  okarakterisane u pogledu hemijskog sastava, poroznosti i baznosti, a zatim je testirana katalitička  aktivnost u transesterifikaciji esterifikovanog ulja koštica šljive. Dominantni elementi u pepelu, kao što  su kalijum, kalcijum i magnezijum, imali su različit sadržaj u sve tri vrste pepela. Najveću katalitičku  aktivnost pokazao je pepeo koštica šljive, zbog čega je dalje istraživan uticaj temperature (40, 50 i 60 °C)  na brzinu reakcije katalizovane ovim pepelom. Konstanta brzine reakcije povećavala se sa porastom  temperature reakcije, a vrednost energije aktivacije je 58,8 kJ mol-1 . Pored toga, pepeo koštica šljive  može se ponovo koristiti kao katalizator nakon rekalcinacije.
PB  - Association of Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Utilization of waste plum stones as a source of oil and catalyst for biodiesel production
T1  - Korišćenje otpadnih koštica šljive kao izvora ulja i katalizatora za  proizvodnju biodizela
VL  - 77
IS  - 1
SP  - 39
EP  - 52
DO  - 10.2298/HEMIND221113009M
ER  - 

@article{
author = "Miladinović, Marija and Pavlović, Stefan and Banković-Ilić, Ivana and Kostić, Milan and Stamenković, Olivera and Veljković, Vlada",
year = "2023",
abstract = "Possibilities of using waste plum stones in biodiesel production were investigated. The plum kernels were used as a source to obtain oil by the Soxhlet extraction method, while the whole plum stones, the plum stone shells that remained after the crashing, and the plum kernel cake that remained after the oil extraction, were burned off to obtain ashes. The collected ashes were characterized by elemental composition, porosity, and base strength and tested for catalytic activity in transesterification of esterified plum kernel oil. Dominant elements were potassium, calcium, and magnesium at different contents in the three obtained ashes. The most active catalyst was the plum stone shell ash, so the effect of temperature (40, 50, and 60°C) on the reaction rate was investigated. The reaction rate constant increased with the reaction temperature with the activation energy value of 58.8 kJ mol-1. In addition, the plum stone shell ash can be reused as a catalyst after recalcination., U ovom radu istraživana je mogućnost korišćenja otpadnih koštica šljive u proizvodnji biodizela. Jezgra  šljive su iskorišćena kao sirovina za dobijanje ulja primenom Soxhlet-ove metode ekstrakcije. Cele  koštice, ljuske koštica šljive i pogača dobijena nakon ekstrakcije ulja iz jezgra šljive spaljeni su da bi se  dobio pepeo, koji je korišćen kao katalizator. Dobijene tri vrste sakupljenog pepela su najpre  okarakterisane u pogledu hemijskog sastava, poroznosti i baznosti, a zatim je testirana katalitička  aktivnost u transesterifikaciji esterifikovanog ulja koštica šljive. Dominantni elementi u pepelu, kao što  su kalijum, kalcijum i magnezijum, imali su različit sadržaj u sve tri vrste pepela. Najveću katalitičku  aktivnost pokazao je pepeo koštica šljive, zbog čega je dalje istraživan uticaj temperature (40, 50 i 60 °C)  na brzinu reakcije katalizovane ovim pepelom. Konstanta brzine reakcije povećavala se sa porastom  temperature reakcije, a vrednost energije aktivacije je 58,8 kJ mol-1 . Pored toga, pepeo koštica šljive  može se ponovo koristiti kao katalizator nakon rekalcinacije.",
publisher = "Association of Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Utilization of waste plum stones as a source of oil and catalyst for biodiesel production, Korišćenje otpadnih koštica šljive kao izvora ulja i katalizatora za  proizvodnju biodizela",
volume = "77",
number = "1",
pages = "39-52",
doi = "10.2298/HEMIND221113009M"
}

Miladinović, M., Pavlović, S., Banković-Ilić, I., Kostić, M., Stamenković, O.,& Veljković, V.. (2023). Utilization of waste plum stones as a source of oil and catalyst for biodiesel production. in Hemijska industrija
Association of Chemical Engineers of Serbia., 77(1), 39-52.
https://doi.org/10.2298/HEMIND221113009M

Miladinović M, Pavlović S, Banković-Ilić I, Kostić M, Stamenković O, Veljković V. Utilization of waste plum stones as a source of oil and catalyst for biodiesel production. in Hemijska industrija. 2023;77(1):39-52.
doi:10.2298/HEMIND221113009M .

Miladinović, Marija, Pavlović, Stefan, Banković-Ilić, Ivana, Kostić, Milan, Stamenković, Olivera, Veljković, Vlada, "Utilization of waste plum stones as a source of oil and catalyst for biodiesel production" in Hemijska industrija, 77, no. 1 (2023):39-52,
https://doi.org/10.2298/HEMIND221113009M . .

TY  - JOUR
AU  - Miladinović, Marija M.
AU  - Krstić, Jugoslav
AU  - Zdujić, Miodrag V.
AU  - Veselinović, Ljiljana M.
AU  - Veljović, Đorđe
AU  - Banković-Ilić, Ivana B.
AU  - Stamenković, Olivera
AU  - Veljković, Vlada B.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4868
AB  - Hazelnut shell ash was investigated as a new base catalyst for the transesterification of used cooking sunflower oil to biodiesel. To understand its catalytic properties, the prepared ash was characterized by EDX, XRD, TGA/DTA, Hg porosimetry, N2 physisorption, FE-SEM, and basic strength measurements. The effects of the catalyst loading in the range of 1–5% of the oil weight and the methanol-to-oil molar ratio of 6:1–18:1 on the kinetics of the fatty acid methyl esters synthesis were established. Moreover, the leaching and reusability of the catalyst were assessed. The obtained results revealed that hazelnut shell ash was mostly composed of K, Ca, and Mg. The highest ester content (98%) was achieved at the catalyst loading of 5%, the methanol-to-oil molar ratio of 12:1, and the reaction time of 10 min. The contribution of homogeneous catalysis because of the catalyst leaching was confirmed but did not determine the overall reaction rate. The catalyst can be reused after the recalcination at 800 °C for 2 h achieving the high methyl esters content (>96%) in 30 min after three subsequent runs. The overall reaction followed the pseudo-first-order kinetics with respect to triacylglycerols. A linear relationship between the apparent reaction rate constant and the catalyst loading and the methanol-to-oil molar ratio was determined. The determined value of the reaction rate constant was 0.0576 dm6/(min•mol2).
PB  - Elsevier
T2  - Renewable Energy
T1  - Transesterification of used cooking sunflower oil catalyzed by hazelnut shell ash
VL  - 183
SP  - 103
EP  - 113
DO  - 10.1016/j.renene.2021.10.071
ER  - 

@article{
author = "Miladinović, Marija M. and Krstić, Jugoslav and Zdujić, Miodrag V. and Veselinović, Ljiljana M. and Veljović, Đorđe and Banković-Ilić, Ivana B. and Stamenković, Olivera and Veljković, Vlada B.",
year = "2022",
abstract = "Hazelnut shell ash was investigated as a new base catalyst for the transesterification of used cooking sunflower oil to biodiesel. To understand its catalytic properties, the prepared ash was characterized by EDX, XRD, TGA/DTA, Hg porosimetry, N2 physisorption, FE-SEM, and basic strength measurements. The effects of the catalyst loading in the range of 1–5% of the oil weight and the methanol-to-oil molar ratio of 6:1–18:1 on the kinetics of the fatty acid methyl esters synthesis were established. Moreover, the leaching and reusability of the catalyst were assessed. The obtained results revealed that hazelnut shell ash was mostly composed of K, Ca, and Mg. The highest ester content (98%) was achieved at the catalyst loading of 5%, the methanol-to-oil molar ratio of 12:1, and the reaction time of 10 min. The contribution of homogeneous catalysis because of the catalyst leaching was confirmed but did not determine the overall reaction rate. The catalyst can be reused after the recalcination at 800 °C for 2 h achieving the high methyl esters content (>96%) in 30 min after three subsequent runs. The overall reaction followed the pseudo-first-order kinetics with respect to triacylglycerols. A linear relationship between the apparent reaction rate constant and the catalyst loading and the methanol-to-oil molar ratio was determined. The determined value of the reaction rate constant was 0.0576 dm6/(min•mol2).",
publisher = "Elsevier",
journal = "Renewable Energy",
title = "Transesterification of used cooking sunflower oil catalyzed by hazelnut shell ash",
volume = "183",
pages = "103-113",
doi = "10.1016/j.renene.2021.10.071"
}

Miladinović, M. M., Krstić, J., Zdujić, M. V., Veselinović, L. M., Veljović, Đ., Banković-Ilić, I. B., Stamenković, O.,& Veljković, V. B.. (2022). Transesterification of used cooking sunflower oil catalyzed by hazelnut shell ash. in Renewable Energy
Elsevier., 183, 103-113.
https://doi.org/10.1016/j.renene.2021.10.071

Miladinović MM, Krstić J, Zdujić MV, Veselinović LM, Veljović Đ, Banković-Ilić IB, Stamenković O, Veljković VB. Transesterification of used cooking sunflower oil catalyzed by hazelnut shell ash. in Renewable Energy. 2022;183:103-113.
doi:10.1016/j.renene.2021.10.071 .

Miladinović, Marija M., Krstić, Jugoslav, Zdujić, Miodrag V., Veselinović, Ljiljana M., Veljović, Đorđe, Banković-Ilić, Ivana B., Stamenković, Olivera, Veljković, Vlada B., "Transesterification of used cooking sunflower oil catalyzed by hazelnut shell ash" in Renewable Energy, 183 (2022):103-113,
https://doi.org/10.1016/j.renene.2021.10.071 . .

TY  - JOUR
AU  - Krstić, Jugoslav
AU  - Nježić, Zvonko B.
AU  - Kostić, Milan D.
AU  - Marić, Boško D.
AU  - Šimurina, Olivera D.
AU  - Stamenković, Olivera
AU  - Veljković, Vlada
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5402
AB  - A solid catalyst was prepared from waste filter cake (WFC) from a sugar beet processing plant and used, after calcination at 900 °C within 2 h, for biodiesel production from rapeseed oil and methanol. The calcined WFC (CFC) catalyst was characterized by XRF, FTIR, XRD, TGA/DTG, TPDe, TPD-CO2, SEM, N2 physisorption, and Hg porosimetry. The CFC is a CaO-based catalyst with a rigid, sustainable macroporous structure with the largest particles of 2.0 × 0.5 µm, a specific surface area of 7.3 m2/g, and a basicity of 0.27 mmol/g. It provides high conversion of 97.9% in 1 h at the methanol-to-oil molar ratio of 9:1, the temperature of 60 °C, and the catalyst loading of 10% of the oil mass. Its catalytic efficiency is comparable to the WFC-based nanocatalysts and CaO-based catalysts from natural sources. CFC was reused twice with a negligible decrease in catalytic activity, ensuring a FAME content above 97% in 1 h. The biodiesel produced from rapeseed oil over the CFC catalyst has good fuel properties that fulfill most of EN 14214. Therefore, WFC is a promising source of a low-cost, highly active, basic, and environmentally friendly CFC catalyst, which could reduce biodiesel production costs. From this point of view, this catalyst has great potential for developing the process at the commercial level.
PB  - Elsevier
T2  - Process Safety and Environmental Protection
T1  - Biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing
VL  - 168
SP  - 463
EP  - 473
DO  - 10.1016/j.psep.2022.10.021
ER  - 

@article{
author = "Krstić, Jugoslav and Nježić, Zvonko B. and Kostić, Milan D. and Marić, Boško D. and Šimurina, Olivera D. and Stamenković, Olivera and Veljković, Vlada",
year = "2022",
abstract = "A solid catalyst was prepared from waste filter cake (WFC) from a sugar beet processing plant and used, after calcination at 900 °C within 2 h, for biodiesel production from rapeseed oil and methanol. The calcined WFC (CFC) catalyst was characterized by XRF, FTIR, XRD, TGA/DTG, TPDe, TPD-CO2, SEM, N2 physisorption, and Hg porosimetry. The CFC is a CaO-based catalyst with a rigid, sustainable macroporous structure with the largest particles of 2.0 × 0.5 µm, a specific surface area of 7.3 m2/g, and a basicity of 0.27 mmol/g. It provides high conversion of 97.9% in 1 h at the methanol-to-oil molar ratio of 9:1, the temperature of 60 °C, and the catalyst loading of 10% of the oil mass. Its catalytic efficiency is comparable to the WFC-based nanocatalysts and CaO-based catalysts from natural sources. CFC was reused twice with a negligible decrease in catalytic activity, ensuring a FAME content above 97% in 1 h. The biodiesel produced from rapeseed oil over the CFC catalyst has good fuel properties that fulfill most of EN 14214. Therefore, WFC is a promising source of a low-cost, highly active, basic, and environmentally friendly CFC catalyst, which could reduce biodiesel production costs. From this point of view, this catalyst has great potential for developing the process at the commercial level.",
publisher = "Elsevier",
journal = "Process Safety and Environmental Protection",
title = "Biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing",
volume = "168",
pages = "463-473",
doi = "10.1016/j.psep.2022.10.021"
}

Krstić, J., Nježić, Z. B., Kostić, M. D., Marić, B. D., Šimurina, O. D., Stamenković, O.,& Veljković, V.. (2022). Biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing. in Process Safety and Environmental Protection
Elsevier., 168, 463-473.
https://doi.org/10.1016/j.psep.2022.10.021

Krstić J, Nježić ZB, Kostić MD, Marić BD, Šimurina OD, Stamenković O, Veljković V. Biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing. in Process Safety and Environmental Protection. 2022;168:463-473.
doi:10.1016/j.psep.2022.10.021 .

Krstić, Jugoslav, Nježić, Zvonko B., Kostić, Milan D., Marić, Boško D., Šimurina, Olivera D., Stamenković, Olivera, Veljković, Vlada, "Biodiesel production from rapeseed oil over calcined waste filter cake from sugar beet processing" in Process Safety and Environmental Protection, 168 (2022):463-473,
https://doi.org/10.1016/j.psep.2022.10.021 . .

TY  - JOUR
AU  - Veličković, Ana
AU  - Avramović, Jelena M.
AU  - Kostić, Milan
AU  - Krstić, Jugoslav
AU  - Stamenković, Olivera
AU  - Veljković, Vlada B.
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4844
AB  - Wheat straw ash (WSA) was investigated as a new catalyst in biodiesel production from sunflower oil. The catalyst was characterized by temperature-programmed decomposition, X-ray powder diffraction, Hg porosimetry, N2 physisorption, and scanning electron microscopy - energy dispersive X-ray spectroscopy methods. The methanolysis reaction was tested in the temperature range of 55–65 oC, the catalyst loading range 10–20 % of the oil weight, and the methanol-to-oil molar ratio range 18 : 1–24 : 1. The reaction conditions of the sunflower oil methanolysis over WSA were optimized by using the response surface methodology in combination with the historical experimental design. The optimum process conditions ensuring the highest fatty acid methyl esters (FAME) content of 98.6 % were the reaction temperature of 60.3 oC, the catalyst loading of 11.6 % (based on the oil weight), the methanol-to-oil molar ratio of 18.3 :1, and the reaction time of 124 min. The values of the statistical criteria, such as coefficients of determination (R2 = 0.811, R2pred = 0.789, R2adj = 0.761) and the mean relative percent deviation (MRPD) value of 10.6 % (66 data) implied the acceptability and precision of the developed model. The FAME content after 4 h of reaction under the optimal conditions decreased to 37, 12, and 3 %, after the first, second, and third reuse, respectively.
AB  - Pepeo pšenične slame (PPS) je korišćen kao katalizator u proizvodnji biodizela iz sunco-kretovog ulja. Karakterizacija katalizatora je izvršena primenom metoda tempera-turski programiranom razgradnjom (temperature-programmed decomposition, TPDe), rentgenskom difrakcijom (X-ray diffraction, XRD), Hg porozimetrijom, N2 fizi-sorpcijom i skenirajućom elektronskom mikrosopijom sa energo-disperzivnom spek-trometrijom (scanning electron microscopy and energy dispersive X-ray spectroscopy, SEM-EDS). Reakcija metanolize istraživana je pri sledećim reakcionim uslovima: tem-peraturni opseg 55-65 °C; količina katalizatora 10-20 % (računato na masu ulja) i opseg molskog odnosa methanol : ulje 18 : 1 – 24 : 1. Optimizacija reakcionih uslova izvršena je metodologijom površine odziva u kombinaciji sa istorijskim eksperimentalnim planom. Maksimalni prinos metil estara masnih kiselina (MEMK) od 98,6 % postignut je pri sledećim optimalnim reakcionim uslovima: temperatura 60,3 oC, količina katalizatora 11,6 % (računato na masu ulja), molski odnos methanol : ulje 18,3 : 1 i vreme trajanja reakcije 124 min. Vrednosti koeficijenata determinacije (R2 = 0,811, R2pred = 0,789, R2adj = 0,761) i srednjeg relativnog odstupanja (10,6 %, 66 podataka) ukazali su na prihvatljivost i pouzdanost razvijenog modela. Sadržaj MEMK nakon 4 h reakcije pri optimalnim uslovima smanjen je na 37, 12 i 3 % nakon prve, druge i treće upotrebe katalizatora, redom.
PB  - Belgrade : Association of the Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Modeling the biodiesel production using the wheat straw ash as a catalyst
T1  - Pepeo pšenične slame kao katalizator u proizvodnji biodizela
VL  - 75
IS  - 5
SP  - 257
EP  - 276
DO  - 10.2298/HEMIND210526028V
ER  - 

@article{
author = "Veličković, Ana and Avramović, Jelena M. and Kostić, Milan and Krstić, Jugoslav and Stamenković, Olivera and Veljković, Vlada B.",
year = "2021",
abstract = "Wheat straw ash (WSA) was investigated as a new catalyst in biodiesel production from sunflower oil. The catalyst was characterized by temperature-programmed decomposition, X-ray powder diffraction, Hg porosimetry, N2 physisorption, and scanning electron microscopy - energy dispersive X-ray spectroscopy methods. The methanolysis reaction was tested in the temperature range of 55–65 oC, the catalyst loading range 10–20 % of the oil weight, and the methanol-to-oil molar ratio range 18 : 1–24 : 1. The reaction conditions of the sunflower oil methanolysis over WSA were optimized by using the response surface methodology in combination with the historical experimental design. The optimum process conditions ensuring the highest fatty acid methyl esters (FAME) content of 98.6 % were the reaction temperature of 60.3 oC, the catalyst loading of 11.6 % (based on the oil weight), the methanol-to-oil molar ratio of 18.3 :1, and the reaction time of 124 min. The values of the statistical criteria, such as coefficients of determination (R2 = 0.811, R2pred = 0.789, R2adj = 0.761) and the mean relative percent deviation (MRPD) value of 10.6 % (66 data) implied the acceptability and precision of the developed model. The FAME content after 4 h of reaction under the optimal conditions decreased to 37, 12, and 3 %, after the first, second, and third reuse, respectively., Pepeo pšenične slame (PPS) je korišćen kao katalizator u proizvodnji biodizela iz sunco-kretovog ulja. Karakterizacija katalizatora je izvršena primenom metoda tempera-turski programiranom razgradnjom (temperature-programmed decomposition, TPDe), rentgenskom difrakcijom (X-ray diffraction, XRD), Hg porozimetrijom, N2 fizi-sorpcijom i skenirajućom elektronskom mikrosopijom sa energo-disperzivnom spek-trometrijom (scanning electron microscopy and energy dispersive X-ray spectroscopy, SEM-EDS). Reakcija metanolize istraživana je pri sledećim reakcionim uslovima: tem-peraturni opseg 55-65 °C; količina katalizatora 10-20 % (računato na masu ulja) i opseg molskog odnosa methanol : ulje 18 : 1 – 24 : 1. Optimizacija reakcionih uslova izvršena je metodologijom površine odziva u kombinaciji sa istorijskim eksperimentalnim planom. Maksimalni prinos metil estara masnih kiselina (MEMK) od 98,6 % postignut je pri sledećim optimalnim reakcionim uslovima: temperatura 60,3 oC, količina katalizatora 11,6 % (računato na masu ulja), molski odnos methanol : ulje 18,3 : 1 i vreme trajanja reakcije 124 min. Vrednosti koeficijenata determinacije (R2 = 0,811, R2pred = 0,789, R2adj = 0,761) i srednjeg relativnog odstupanja (10,6 %, 66 podataka) ukazali su na prihvatljivost i pouzdanost razvijenog modela. Sadržaj MEMK nakon 4 h reakcije pri optimalnim uslovima smanjen je na 37, 12 i 3 % nakon prve, druge i treće upotrebe katalizatora, redom.",
publisher = "Belgrade : Association of the Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Modeling the biodiesel production using the wheat straw ash as a catalyst, Pepeo pšenične slame kao katalizator u proizvodnji biodizela",
volume = "75",
number = "5",
pages = "257-276",
doi = "10.2298/HEMIND210526028V"
}

Veličković, A., Avramović, J. M., Kostić, M., Krstić, J., Stamenković, O.,& Veljković, V. B.. (2021). Modeling the biodiesel production using the wheat straw ash as a catalyst. in Hemijska industrija
Belgrade : Association of the Chemical Engineers of Serbia., 75(5), 257-276.
https://doi.org/10.2298/HEMIND210526028V

Veličković A, Avramović JM, Kostić M, Krstić J, Stamenković O, Veljković VB. Modeling the biodiesel production using the wheat straw ash as a catalyst. in Hemijska industrija. 2021;75(5):257-276.
doi:10.2298/HEMIND210526028V .

Veličković, Ana, Avramović, Jelena M., Kostić, Milan, Krstić, Jugoslav, Stamenković, Olivera, Veljković, Vlada B., "Modeling the biodiesel production using the wheat straw ash as a catalyst" in Hemijska industrija, 75, no. 5 (2021):257-276,
https://doi.org/10.2298/HEMIND210526028V . .

TY  - JOUR
AU  - Pavlović, Stefan
AU  - Marinković, Dalibor
AU  - Kostić, Milan
AU  - Lončarević, Davor
AU  - Mojović, Ljiljana
AU  - Stanković, Miroslav
AU  - Veljković, Vlada B.
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4035
AB  - Lignite coal fly ash (FA) from a domestic thermal power plant was converted into a pure cancrinite zeolitic material (ZMFA) using a novel, custom-made, rotating autoclave reactor system by a short-term alkali activation process. The obtained ZMFA was used as catalyst support of calcium oxide as an active component derived from waste chicken eggshells (ES). The ZMFA supported calcium oxide catalyst (xCaO/ZMFA) was synthesized by means of the ultrasound-assisted method. The influence of different concentrations of dispersed calcium oxide (x = 5–20 wt%) over ZMFA and thermal treatment at different temperatures (450–600 °C) were studied. The structural and morphological characterization showed that the original cancrinite structure was preserved. The basicity and textural properties indicated the presence of strong active sites in a well-defined pore network suitable for the reactions of bulky organic compounds such as triacylglycerols (TAGs). The highest activity (96.5% of fatty acid methyl esters) in the methanolysis of sunflower oil was achieved with the 20CaO/ZMFA catalyst under reaction conditions: temperature of 60 °C, methanol/oil molar ratio of 12:1, catalyst concentration of 4 wt%, and reaction time of 2 h. It was found that the optimal calcination temperature of the catalyst precursor was 550 °C. At calcination temperatures above 550 °C, the melting of the glassy phase became more intense whereby the molten phase partially reacted with calcium oxide forming the catalytically inactive calcium silicate compounds (wollastonite, larnite, etc.). The rate constants of the two tested kinetic models were correlated with the concentrations of active calcium oxide. The MRPD of both models was low indicating their reliability.
PB  - Elsevier
T2  - Fuel
T1  - The chicken eggshell calcium oxide ultrasonically dispersed over lignite coal fly ash-based cancrinite zeolite support as a catalyst for biodiesel production
VL  - 289
SP  - 119912
DO  - 10.1016/j.fuel.2020.119912
ER  - 

@article{
author = "Pavlović, Stefan and Marinković, Dalibor and Kostić, Milan and Lončarević, Davor and Mojović, Ljiljana and Stanković, Miroslav and Veljković, Vlada B.",
year = "2021",
abstract = "Lignite coal fly ash (FA) from a domestic thermal power plant was converted into a pure cancrinite zeolitic material (ZMFA) using a novel, custom-made, rotating autoclave reactor system by a short-term alkali activation process. The obtained ZMFA was used as catalyst support of calcium oxide as an active component derived from waste chicken eggshells (ES). The ZMFA supported calcium oxide catalyst (xCaO/ZMFA) was synthesized by means of the ultrasound-assisted method. The influence of different concentrations of dispersed calcium oxide (x = 5–20 wt%) over ZMFA and thermal treatment at different temperatures (450–600 °C) were studied. The structural and morphological characterization showed that the original cancrinite structure was preserved. The basicity and textural properties indicated the presence of strong active sites in a well-defined pore network suitable for the reactions of bulky organic compounds such as triacylglycerols (TAGs). The highest activity (96.5% of fatty acid methyl esters) in the methanolysis of sunflower oil was achieved with the 20CaO/ZMFA catalyst under reaction conditions: temperature of 60 °C, methanol/oil molar ratio of 12:1, catalyst concentration of 4 wt%, and reaction time of 2 h. It was found that the optimal calcination temperature of the catalyst precursor was 550 °C. At calcination temperatures above 550 °C, the melting of the glassy phase became more intense whereby the molten phase partially reacted with calcium oxide forming the catalytically inactive calcium silicate compounds (wollastonite, larnite, etc.). The rate constants of the two tested kinetic models were correlated with the concentrations of active calcium oxide. The MRPD of both models was low indicating their reliability.",
publisher = "Elsevier",
journal = "Fuel",
title = "The chicken eggshell calcium oxide ultrasonically dispersed over lignite coal fly ash-based cancrinite zeolite support as a catalyst for biodiesel production",
volume = "289",
pages = "119912",
doi = "10.1016/j.fuel.2020.119912"
}

Pavlović, S., Marinković, D., Kostić, M., Lončarević, D., Mojović, L., Stanković, M.,& Veljković, V. B.. (2021). The chicken eggshell calcium oxide ultrasonically dispersed over lignite coal fly ash-based cancrinite zeolite support as a catalyst for biodiesel production. in Fuel
Elsevier., 289, 119912.
https://doi.org/10.1016/j.fuel.2020.119912

Pavlović S, Marinković D, Kostić M, Lončarević D, Mojović L, Stanković M, Veljković VB. The chicken eggshell calcium oxide ultrasonically dispersed over lignite coal fly ash-based cancrinite zeolite support as a catalyst for biodiesel production. in Fuel. 2021;289:119912.
doi:10.1016/j.fuel.2020.119912 .

Pavlović, Stefan, Marinković, Dalibor, Kostić, Milan, Lončarević, Davor, Mojović, Ljiljana, Stanković, Miroslav, Veljković, Vlada B., "The chicken eggshell calcium oxide ultrasonically dispersed over lignite coal fly ash-based cancrinite zeolite support as a catalyst for biodiesel production" in Fuel, 289 (2021):119912,
https://doi.org/10.1016/j.fuel.2020.119912 . .