Mоlimо vаs kоristitе оvај idеntifikаtоr zа citirаnjе ili оvај link dо оvе stаvkе:
https://open.uns.ac.rs/handle/123456789/31221
Nаziv: | Activation temperature imposed textural and surface synergism of CaO catalyst for sunflower oil transesterification | Аutоri: | Mićić Radoslav Bošnjak Kiralj Milica Panić Sanja Tomić Milan Jović Branislav Bošković Goran |
Dаtum izdаvаnjа: | 2015 | Čаsоpis: | Fuel | Sažetak: | © 2015 Elsevier Ltd. All rights reserved. Catalytic activity of calcium oxide as a heterogeneous catalyst was investigated for transesterification of sunflower oil to methyl esters. The primary objective of this study was to investigate the catalyst activity (biodiesel yield) as a function of its active phase and textural properties imposed by different activation temperatures: 500, 700, 800, 900, 1000 and 1100 °C. Therefore the catalyst activity, basicity, textural and bulk properties were correlated. X-ray diffraction analysis (XRD) showed Ca(OH)<inf>2</inf> next to CaO phase in all samples activated up to 900 °C. Their fraction changed, however, with activation temperature increase, leading to pure CaO in samples activated above 900 °C. The same samples, however, performed with the lowest activity in the series, in which the catalyst sample calcined at 800 °C showed the maximal activity. Simultaneous thermal analysis (TG-DTA) indicated two-step dehydroxylation of CaO, suggesting different fractions but also positions of hydroxyl groups upon calcination at different temperatures. Both Fourier transformed infrared spectroscopy (FTIR) and temperature programmed desorption (TPD) of CO<inf>2</inf> preadsorbed on CaO surface indicated the sample activated at 700 °C with the highest basicity. It is unique in the series containing basic sites of both strong and medium strength. High basicity of that sample, however, happened not to be enough for the highest activity, possibly due to poor textural properties, as revealed by results of low temperature nitrogen adsorption (LTNA). Maximal specific surface area, total pore volume and dominant fraction of a high-diameter mesopores were found in the case of the sample activated at 800 °C. Thus, a complex function of active sites of medium strength, possibly induced by a specific hydroxyl groups coverage, as well as mesoporosity directing an unrestricted mass transfer, resulted in the maximal activity of the CaO sample activated at 800 °C. | URI: | https://open.uns.ac.rs/handle/123456789/31221 | ISSN: | 0016-2361 | DOI: | 10.1016/j.fuel.2015.07.025 |
Nаlаzi sе u kоlеkciјаmа: | PMF Publikacije/Publications TF Publikacije/Publications |
Prikаzаti cеlоkupаn zаpis stаvki
SCOPUSTM
Nаvоđеnjа
18
prоvеrеnо 10.05.2024.
Prеglеd/i stаnicа
41
Prоtеklа nеdеljа
2
2
Prоtеkli mеsеc
4
4
prоvеrеnо 10.05.2024.
Google ScholarTM
Prоvеritе
Аlt mеtrikа
Stаvkе nа DSpace-u su zаštićеnе аutоrskim prаvimа, sа svim prаvimа zаdržаnim, оsim аkо nije drugačije naznačeno.