Performance Comparison of Heterogeneous Catalysts based on Natural Bangka Kaolin for Biodiesel Production by Acid and Base Activation Processes

This study is aimed to evaluate efficiency low-cost natural kaolin from Bangka island as a catalyst to produce biodiesel (fatty acid methyl ester, FAME) via the transesterification reaction using the cooking oil as a model of free fatty acids (FFA) source. Heterogeneous catalysts of the natural kaolin were prepared by an activation process using base (1-2 M NaOH) and acid (1 M HCl) solution. The base and acid activated kaolin are labelled as Kb1M, Kb2M, and Ka1M, respectively. The quality of biodiesel was analyzed according to the SNI 04-7182-2015 method, the American Society for Testing and Materials (ASTM) D 6751, and the Europäische Norm (EN) 14214, while the composition of biodiesel was determined using gas chromatography-mass spectrometry (GC-MS) analysis. Among the activated kaolin, the Kb2M showed the best heterogenous catalyst performance, producing 96.3% methyl ester with a yield of 69.4%. The highest FAME conversion was achieved using the Kb1M catalyst at 79.1% with a mole ratio of cooking oil to methanol being 1:3, whereas the lowest FAME conversion, 72.0%, was obtained using the Kb2M catalyst with a mole ratio of cooking oil to methanol being 1:6. Overall, the Kb2M showed the best efficient catalyst, while the Ka1M showed the lowest catalytic performance.