Resumen
The implementation of biomass sources as carbon precursor to synthesise heterogeneous solid catalyst for biodiesel production had drawn attention from researchers because it was less expensive and could reduce the generation of biomass waste. In this research, the synthesis of biomass-based catalysts and the effect of pre-treatment conditions on catalytic performance were investigated. Oil palm frond with particles size of 300µm was selected whereas potassium hydroxide was chosen as an activating agent due to its better impregnation effect as compared to phosphoric acid. The effect of pre-treatment conditions was studied by manipulating the carbonisation temperatures (400?, 600? and 800?), impregnation weight ratios of oil palm frond to potassium hydroxide (1:0.5, 1:1 and 1:1.5) and impregnation temperatures (50?, 70? and 90?). Esterification was carried out using palm fatty acid distillate at reaction condition of 100? for 6h, 1wt% catalyst loading and methanol to oil molar ratio of 10:1. Various sulfonation methods such as direct sulfonation, 4-benzenediazonium sulfonate and decomposition of ammonium persulfate were also implemented and their effect on catalytic performance was compared. The biodiesel yield and conversion were determined by gas chromatography and acid value test. Characterisation of raw oil palm frond, impregnated oil palm frond, activated carbon and catalyst were conducted to investigate the surface morphology with Scanning Electron Microscopy, elemental composition with Energy-Dispersive X-ray Spectroscopy, the presence of functional groups with Fourier Transform Infrared Spectroscopy, thermal stability with Thermogravimetric Analysis and effective reduction temperature with Temperature Programmed Reduction. The results showed that the optimum pre-treatment condition was achieved at maximum biodiesel yield and conversion of 92.27% and 96.53%, respectively, at carbonisation temperature of 600?, impregnation ratio of 1:1.5 and impregnation temperature of 90?. The renewable catalyst provided an alternative catalyst synthesis pathway which was more sustainable in the long run.