TY  - CONF
AU  - Pavlović, Stefan
AU  - Marinković, Dalibor
AU  - Milovanović, Biljana
AU  - Tišma, Marina
AU  - Mojović, Ljiljana
AU  - Stanković, Miroslav
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4721
AB  - Waste-based zeolite supported CaO catalyst (20CaO/ZMFA) was synthesized by ultrasound-assisted impregnation from alcoholic suspension. Zeolite was previously synthesized from lignite coal fly ash (FA) by alkali activation in miniature rotating autoclave reactors (6.25 M NaOH, 260 °C, 4 h), whereas CaO was prepared by chicken eggshell (ES) calcination (900 ºC, 4 h). The final catalyst was obtained by precursor calcination at 550 °C, 4 h. The obtained catalyst was used for catalyst stability tests (reusability and leaching) in transesterification (methanol/oil molar ratio of 12/1, catalyst concentration of 4 wt%, and temperature of 60 °C) of three types of oily feedstocks, fresh sunflower oil (SFO), waste cooking oil (WCO) and model thermal treated (230 °C, 5 days) sunflower oil (SFOTT). The concentration of triacylglycerols (TAGs) and fatty acid methyl esters (FAMEs) was determined by GC and HPLC, respectively. The 20CaO/ZMFA exhibited high activity (FAME content > 96.5 % for 180 min) in the transesterification of all three oily feedstocks. The stability tests are shown that catalyst is stable even in four reaction cycles for SFO and WCO, whereas the Ca 2+ leaching was significantly lower compared to similar catalytic systems.
PB  - Fuel Science Center
C3  - 9th International Conference Fuel Science - From Production to Propulsion 2021
T1  - Stability of waste-based zeolite supported CaO catalyst for biodiesel production from waste oily feedstocks
UR  - https://hdl.handle.net/21.15107/rcub_cer_4721
ER  - 

@conference{
author = "Pavlović, Stefan and Marinković, Dalibor and Milovanović, Biljana and Tišma, Marina and Mojović, Ljiljana and Stanković, Miroslav",
year = "2021",
abstract = "Waste-based zeolite supported CaO catalyst (20CaO/ZMFA) was synthesized by ultrasound-assisted impregnation from alcoholic suspension. Zeolite was previously synthesized from lignite coal fly ash (FA) by alkali activation in miniature rotating autoclave reactors (6.25 M NaOH, 260 °C, 4 h), whereas CaO was prepared by chicken eggshell (ES) calcination (900 ºC, 4 h). The final catalyst was obtained by precursor calcination at 550 °C, 4 h. The obtained catalyst was used for catalyst stability tests (reusability and leaching) in transesterification (methanol/oil molar ratio of 12/1, catalyst concentration of 4 wt%, and temperature of 60 °C) of three types of oily feedstocks, fresh sunflower oil (SFO), waste cooking oil (WCO) and model thermal treated (230 °C, 5 days) sunflower oil (SFOTT). The concentration of triacylglycerols (TAGs) and fatty acid methyl esters (FAMEs) was determined by GC and HPLC, respectively. The 20CaO/ZMFA exhibited high activity (FAME content > 96.5 % for 180 min) in the transesterification of all three oily feedstocks. The stability tests are shown that catalyst is stable even in four reaction cycles for SFO and WCO, whereas the Ca 2+ leaching was significantly lower compared to similar catalytic systems.",
publisher = "Fuel Science Center",
journal = "9th International Conference Fuel Science - From Production to Propulsion 2021",
title = "Stability of waste-based zeolite supported CaO catalyst for biodiesel production from waste oily feedstocks",
url = "https://hdl.handle.net/21.15107/rcub_cer_4721"
}

Pavlović, S., Marinković, D., Milovanović, B., Tišma, M., Mojović, L.,& Stanković, M.. (2021). Stability of waste-based zeolite supported CaO catalyst for biodiesel production from waste oily feedstocks. in 9th International Conference Fuel Science - From Production to Propulsion 2021
Fuel Science Center..
https://hdl.handle.net/21.15107/rcub_cer_4721

Pavlović S, Marinković D, Milovanović B, Tišma M, Mojović L, Stanković M. Stability of waste-based zeolite supported CaO catalyst for biodiesel production from waste oily feedstocks. in 9th International Conference Fuel Science - From Production to Propulsion 2021. 2021;.
https://hdl.handle.net/21.15107/rcub_cer_4721 .

Pavlović, Stefan, Marinković, Dalibor, Milovanović, Biljana, Tišma, Marina, Mojović, Ljiljana, Stanković, Miroslav, "Stability of waste-based zeolite supported CaO catalyst for biodiesel production from waste oily feedstocks" in 9th International Conference Fuel Science - From Production to Propulsion 2021 (2021),
https://hdl.handle.net/21.15107/rcub_cer_4721 .

TY  - JOUR
AU  - Pavlović, Stefan
AU  - Šelo, Gordana
AU  - Marinković, Dalibor
AU  - Planinić, Mirela
AU  - Tišma, Marina
AU  - Stanković, Miroslav
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4138
AB  - The statistical experimental design (DoE) and optimization (Response Surface Methodology combined with Box–Behnken design) of sunflower oil transesterification catalyzed by waste chicken eggshell-based catalyst were conducted in a custom-made microreactor at 60 °C. The catalyst was synthesized by the hydration–dehydration method and subsequent calcination at 600 °C. Comprehensive characterization of the obtained catalyst was conducted using: X-ray powder diffractometry (XRD), X-ray fluorescence (XRF), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), N2 physisorption, and Hg-porosimetry. Structural, morphological, and textural results showed that the obtained catalyst exhibited high porosity and regular dispersity of plate-like CaO as an active species. The obtained optimal residence time, catalyst concentration, and methanol/oil volume ratio for the continuous reaction in microreactor were 10 min, 0.1 g g−1, and 3:1, respectively. The analysis of variance (ANOVA) showed that the obtained reduced quadratic model was adequate for experimental results fitting. The reaction in the microreactor was significantly intensified compared to a conventional batch reactor, as seen through the fatty acid methyl esters (FAMEs) content after 10 min, which was 51.2% and 18.6%, respectively.
PB  - MDPI
T2  - Micromachines
T1  - Transesterification of Sunflower Oil Over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study
VL  - 12
IS  - 2
SP  - 120
DO  - 10.3390/mi12020120
ER  - 

@article{
author = "Pavlović, Stefan and Šelo, Gordana and Marinković, Dalibor and Planinić, Mirela and Tišma, Marina and Stanković, Miroslav",
year = "2021",
abstract = "The statistical experimental design (DoE) and optimization (Response Surface Methodology combined with Box–Behnken design) of sunflower oil transesterification catalyzed by waste chicken eggshell-based catalyst were conducted in a custom-made microreactor at 60 °C. The catalyst was synthesized by the hydration–dehydration method and subsequent calcination at 600 °C. Comprehensive characterization of the obtained catalyst was conducted using: X-ray powder diffractometry (XRD), X-ray fluorescence (XRF), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), N2 physisorption, and Hg-porosimetry. Structural, morphological, and textural results showed that the obtained catalyst exhibited high porosity and regular dispersity of plate-like CaO as an active species. The obtained optimal residence time, catalyst concentration, and methanol/oil volume ratio for the continuous reaction in microreactor were 10 min, 0.1 g g−1, and 3:1, respectively. The analysis of variance (ANOVA) showed that the obtained reduced quadratic model was adequate for experimental results fitting. The reaction in the microreactor was significantly intensified compared to a conventional batch reactor, as seen through the fatty acid methyl esters (FAMEs) content after 10 min, which was 51.2% and 18.6%, respectively.",
publisher = "MDPI",
journal = "Micromachines",
title = "Transesterification of Sunflower Oil Over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study",
volume = "12",
number = "2",
pages = "120",
doi = "10.3390/mi12020120"
}

Pavlović, S., Šelo, G., Marinković, D., Planinić, M., Tišma, M.,& Stanković, M.. (2021). Transesterification of Sunflower Oil Over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study. in Micromachines
MDPI., 12(2), 120.
https://doi.org/10.3390/mi12020120

Pavlović S, Šelo G, Marinković D, Planinić M, Tišma M, Stanković M. Transesterification of Sunflower Oil Over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study. in Micromachines. 2021;12(2):120.
doi:10.3390/mi12020120 .

Pavlović, Stefan, Šelo, Gordana, Marinković, Dalibor, Planinić, Mirela, Tišma, Marina, Stanković, Miroslav, "Transesterification of Sunflower Oil Over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study" in Micromachines, 12, no. 2 (2021):120,
https://doi.org/10.3390/mi12020120 . .

TY  - CHAP
AU  - Stanković, Miroslav
AU  - Pavlović, Stefan
AU  - Marinković, Dalibor
AU  - Tišma, Marina
AU  - Gabrovska, Margarita
AU  - Nikolova, Dimitrinka
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3743
AB  - Coal fly ash (CFA) is generated during the combustion of coal for energy production. Many studies are based on its utilization as the most abundant, cheap
aluminosilicate industrial residue, which is recognized as a risk for the environment and human health. The present review is focused on CFA origin, chemical properties, and its catalytic application for biodiesel production. The aluminosilicate nature and the presence of rare earth elements make CFA suitable for different adsorption, catalytic, and extraction processes for obtaining valuable products including alternative fuels and pure elements. However, the presence of toxic elements is a potential environmental problem, which should be solved in order to avoid soil, water, and air pollution. The most used modification methods are alkali activation, hydrothermal, and thermal treatment that improve the structural, morphological, and textural properties. The active catalytic form could be obtained by impregnation or ion exchange method. It was found that such synthesized materials have significant catalytic potential in the biofuel chemistry. In the case of biodiesel production, the high values of conversion or yield can be achieved under mild low-energy reaction conditions in the presence of low-cost waste-based catalysts.
PB  - IntechOpen
T2  - Renewable Energy – Resources, Challenges and Applications
T1  - Solid green biodiesel catalysts derived from coal fly ash
SP  - 185
EP  - 208
DO  - 10.5772/intechopen.91703
ER  - 

@inbook{
author = "Stanković, Miroslav and Pavlović, Stefan and Marinković, Dalibor and Tišma, Marina and Gabrovska, Margarita and Nikolova, Dimitrinka",
year = "2020",
abstract = "Coal fly ash (CFA) is generated during the combustion of coal for energy production. Many studies are based on its utilization as the most abundant, cheap
aluminosilicate industrial residue, which is recognized as a risk for the environment and human health. The present review is focused on CFA origin, chemical properties, and its catalytic application for biodiesel production. The aluminosilicate nature and the presence of rare earth elements make CFA suitable for different adsorption, catalytic, and extraction processes for obtaining valuable products including alternative fuels and pure elements. However, the presence of toxic elements is a potential environmental problem, which should be solved in order to avoid soil, water, and air pollution. The most used modification methods are alkali activation, hydrothermal, and thermal treatment that improve the structural, morphological, and textural properties. The active catalytic form could be obtained by impregnation or ion exchange method. It was found that such synthesized materials have significant catalytic potential in the biofuel chemistry. In the case of biodiesel production, the high values of conversion or yield can be achieved under mild low-energy reaction conditions in the presence of low-cost waste-based catalysts.",
publisher = "IntechOpen",
journal = "Renewable Energy – Resources, Challenges and Applications",
booktitle = "Solid green biodiesel catalysts derived from coal fly ash",
pages = "185-208",
doi = "10.5772/intechopen.91703"
}

Stanković, M., Pavlović, S., Marinković, D., Tišma, M., Gabrovska, M.,& Nikolova, D.. (2020). Solid green biodiesel catalysts derived from coal fly ash. in Renewable Energy – Resources, Challenges and Applications
IntechOpen., 185-208.
https://doi.org/10.5772/intechopen.91703

Stanković M, Pavlović S, Marinković D, Tišma M, Gabrovska M, Nikolova D. Solid green biodiesel catalysts derived from coal fly ash. in Renewable Energy – Resources, Challenges and Applications. 2020;:185-208.
doi:10.5772/intechopen.91703 .

Stanković, Miroslav, Pavlović, Stefan, Marinković, Dalibor, Tišma, Marina, Gabrovska, Margarita, Nikolova, Dimitrinka, "Solid green biodiesel catalysts derived from coal fly ash" in Renewable Energy – Resources, Challenges and Applications (2020):185-208,
https://doi.org/10.5772/intechopen.91703 . .

TY  - CONF
AU  - Pavlović, Stefan
AU  - Marinković, Dalibor
AU  - Tišma, Marina
AU  - Stanković, Miroslav
PY  - 2020
UR  - https://www.fuelcenter.rwth-aachen.de/cms/Fuelcenter/Austausch/Internationale-Konferenz/~dcsks/8-Internationale-Konferenz/lidx/1/
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3744
AB  - Calcium oxide was derived from chicken eggshell (ES) by calcination at 900 °C. To improve catalyst performance, the catalyst was treated by the hydration-dehydration method. The new catalyst, with improved structural and morphological properties, denoted as ESHC-600, was obtained and used in methanolysis reaction. Methanolysis reaction was carried out in a microreactor system equipped with two microfluidic syringe pumps. ESHC-600 catalyst was suspended in sunflower oil and added in the first syringe, whereas methanol was placed in the second one. Microchannel with an internal diameter of 0.6 mm was connected with syringes by a T-shaped three-way junction and immersed in the thermostated water bath (60 °C). The reaction parameters are optimized in the following range: catalyst concentration (0.05, 0.075, and 0.1 g/g), methanol to oil volume ratio (1:2, 2:1, and 3:1) and residence time (4, 7, and 10 min). Design of the experiment was created according to three-level full functional design. The response variable was FAME content, which was determined by the HPLC method. It can be noted, that the catalyst exhibits satisfactory catalytic activity in such specific reactor systems in which two immiscible liquids and a solid catalyst interact at a micro-level. Namely, each segment represents one microreactor, thus achieving enhanced miscibility with suppressing external diffusion limitations. Determined optimal reaction conditions were: catalyst concentration of 10 wt%, methanol to oil volume ratio of 3:1, and residence time of 10 min. FAME content in microreactor (54.8 % FAME) was 5 times higher compared with the reaction in a batch reactor (10.3 % FAME) under optimal conditions. Also, it is important to note that potential problem in such microreactor systems represents catalyst precipitation in the syringe, which is particularly pronounced at longer residence time. Such behavior of the catalyst leads to a decline of catalytic activity due to non-uniformly catalyst concentration during the reaction, which can be overcome by pre-treatment of the catalyst-oil suspension under ultrasonic conditions. According to obtained results, such designed reaction systems can be used in biodiesel production in a large scale using sustainable, green, and energy-efficient processes, whereby productivity would be increased by connecting more of these reactors in series.
PB  - Cluster of Excellence The Fuel Science Center
T1  - Optimization of heterogeneously catalyzed methanolysis in microreactor using a green eggshell catalyst
UR  - https://hdl.handle.net/21.15107/rcub_cer_3744
ER  - 

@conference{
author = "Pavlović, Stefan and Marinković, Dalibor and Tišma, Marina and Stanković, Miroslav",
year = "2020",
abstract = "Calcium oxide was derived from chicken eggshell (ES) by calcination at 900 °C. To improve catalyst performance, the catalyst was treated by the hydration-dehydration method. The new catalyst, with improved structural and morphological properties, denoted as ESHC-600, was obtained and used in methanolysis reaction. Methanolysis reaction was carried out in a microreactor system equipped with two microfluidic syringe pumps. ESHC-600 catalyst was suspended in sunflower oil and added in the first syringe, whereas methanol was placed in the second one. Microchannel with an internal diameter of 0.6 mm was connected with syringes by a T-shaped three-way junction and immersed in the thermostated water bath (60 °C). The reaction parameters are optimized in the following range: catalyst concentration (0.05, 0.075, and 0.1 g/g), methanol to oil volume ratio (1:2, 2:1, and 3:1) and residence time (4, 7, and 10 min). Design of the experiment was created according to three-level full functional design. The response variable was FAME content, which was determined by the HPLC method. It can be noted, that the catalyst exhibits satisfactory catalytic activity in such specific reactor systems in which two immiscible liquids and a solid catalyst interact at a micro-level. Namely, each segment represents one microreactor, thus achieving enhanced miscibility with suppressing external diffusion limitations. Determined optimal reaction conditions were: catalyst concentration of 10 wt%, methanol to oil volume ratio of 3:1, and residence time of 10 min. FAME content in microreactor (54.8 % FAME) was 5 times higher compared with the reaction in a batch reactor (10.3 % FAME) under optimal conditions. Also, it is important to note that potential problem in such microreactor systems represents catalyst precipitation in the syringe, which is particularly pronounced at longer residence time. Such behavior of the catalyst leads to a decline of catalytic activity due to non-uniformly catalyst concentration during the reaction, which can be overcome by pre-treatment of the catalyst-oil suspension under ultrasonic conditions. According to obtained results, such designed reaction systems can be used in biodiesel production in a large scale using sustainable, green, and energy-efficient processes, whereby productivity would be increased by connecting more of these reactors in series.",
publisher = "Cluster of Excellence The Fuel Science Center",
title = "Optimization of heterogeneously catalyzed methanolysis in microreactor using a green eggshell catalyst",
url = "https://hdl.handle.net/21.15107/rcub_cer_3744"
}

Pavlović, S., Marinković, D., Tišma, M.,& Stanković, M.. (2020). Optimization of heterogeneously catalyzed methanolysis in microreactor using a green eggshell catalyst. 
Cluster of Excellence The Fuel Science Center..
https://hdl.handle.net/21.15107/rcub_cer_3744

Pavlović S, Marinković D, Tišma M, Stanković M. Optimization of heterogeneously catalyzed methanolysis in microreactor using a green eggshell catalyst. 2020;.
https://hdl.handle.net/21.15107/rcub_cer_3744 .

Pavlović, Stefan, Marinković, Dalibor, Tišma, Marina, Stanković, Miroslav, "Optimization of heterogeneously catalyzed methanolysis in microreactor using a green eggshell catalyst" (2020),
https://hdl.handle.net/21.15107/rcub_cer_3744 .