Methyl ester production from palm fatty acid distillate (PFAD) using sulfonated cow dung-derived carbon-based solid acid catalyst

Abstract

In present work, cow dung was chosen as the raw material to undergo incomplete carbonization process which was held at 500 °C for 2 h. The incomplete carbonized carbon was then sulfonated with H2SO4 at different sulfonation time (2 h, 5 h and 10 h) in studying the relationship between sulfonation time and the activity of the catalyst. From the TPD-NH3 analysis, sulfonated carbon catalyst derived cow dung at 10 h (SCD-(10) catalyst) was chosen due to the higher acid density which is 16,653.49 μmol/g. Meanwhile, the experimental results showed that SCD-(10) catalyst exhibited good catalytic activity with high FFA conversion of 96.5% at optimum parameter of 18:1 methanol to PFAD molar ratio, 4 wt% of catalyst loading and 90 °C reaction temperature within 1 h reaction time. The catalyst was successfully reused for 7 cycles and it was found that the catalytic activity maintained with >90% of FFA conversion for the first three run. SCD-(10) catalyst can be easily recovered and regenerated by simple washing method. Cow dung derived carbon catalyst concluded to be environmentally friendly and efficient for biodiesel production.