Decrease of free fatty acid content in vegetable oil using silica supported ferric sulfate catalyst
Authorized Users Only
Article (Published version)
MetadataShow full item record
A difficulty of biodiesel synthesis based on alkaline catalysts obviously exists if free fatty acids (FFAs) content in vegetable oil is above 0.5 wt.%. In this study, the ferric sulfate supported on silica (Fe-2(SO4)(3)/SiO2) was synthesized, activated (at different temperature: 120-600 degrees C) and tested for heterogeneous esterification of FFA (oleic acid) present in sunflower oil (5 wt.%). The catalyst samples were characterized by BET, TG/DTG, XRD and FTIR analyses. Obtained results showed that catalyst activated at 500 degrees C for 2 h in air atmosphere gave the maximal conversion of oleic acid (similar to 97%). Repeated use of catalyst without additional catalyst treatment or re-activation indicated that catalyst posses desired stability and activity. A pseudo-homogeneous kinetic model was proposed with good agreement between calculated and experimental data.
Keywords:Free fatty acids / Biodiesel / Esterification / Kinetics / Heterogeneous catalysis
Source:Fuel, 2012, 97, 595-602
- Elsevier Sci Ltd, Oxford