Synthesis and Characterization of Novel Corncob-Based Solid Acid Catalyst for Biodiesel Production

In the present study, highly efficient catalysts based on corncob were synthesized for the esterification process. The synthesized catalysts were characterized by BET, XRD, and FT-IR. The effect of catalyst impregnation, carbonation, and sulfonation was studied in detail. The highest conversion of oleic acid (similar to 94.4%) was observed using a catalyst synthesized at H3PO4 impregnation ratio = 1 and time = 5 h; carbonization temperature = 723 K and time = 8 h; sulfonation temperature = 393 K and time = 15 h. Further, the performance of the catalyst was studied for the esterification of fatty acids (FAs) and free fatty acids (FFAs) present in Karanja oil. The catalyst showed similar to 90% conversion of FAs/FFAs within 2 h at 338 K using a molar ratio of 1:10 (FA to methanol)/1:20 (Karanja oil to methanol) and a catalyst loading of 10 wt %. Furthermore, the reusability test of the catalyst revealed that it can be used for 20 times in a batch reactor to give similar to 90% conversion of the oleic acid.