Alkaline Earth Metal Oxide Catalysts for Biodiesel Production from Palm Oil: Elucidation of Process Behaviors and Modeling Using Response Surface Methodology

• Main Authors: Babak Salamatinia, Iman Hashemizadeh, Abdullah Ahmad Zuhairi
• Format: Article
• Language: English
• Published: Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR 2013-03-01
• Series: Iranian Journal of Chemistry & Chemical Engineering
• Subjects: biodiesel; alkaline earth metal oxides; process behavior; historical design; simulation; lixiviation
• Online Access: http://www.ijcce.ac.ir/article_5911_2d0f5b739d2e198c4879bc5b6cf25ebc.pdf
• ISSN: 1021-9986; 1021-9986

Four different alkaline earth metal oxides i.e. MgO, CaO, SrO and BaO were used as heterogeneous catalysts for biodiesel production from palm oil. Effects of critical process variables i.e. reaction time, methanol to oil ratio and temperature were investigated. The results were then fitted to a historical design to study the Analysis of Variance (ANOVA), to characterize interactions between variables and to simulate the process. MgO did not show good catalytic activity while  CaO produced undesired products at longer reaction time. BaO showed the best biodiesel result with a yield of up to 95 %, followed by SrO with a yield of 91 %. A methanol to oil ratio of 9:1 and 60 ºC were found to be the optimum conditions. The experimental data were satisfactorily predicted at 99 % confidence level under various conditions with R2 values higher than 0.92. Characterizations of the catalysts before and after the transesterification process were also performed using a surface analyzer, scanning electron microscopy, Hammett indicator and Atomic Absorption Spectrophotometeric (AAS) methods. The catalytic activity was in the order of BaO > SrO > CaO. However, due to lixiviation of BaO in the product, SrO was found to be the most potential catalyst.