Production of Waste Animal Bone as a Heterogeneous Solid Base Catalyst for Transesterification of Jatropha Oil

Abstract

Heterogeneous catalyst plays a vital role in transesterification process, especially in view of cost and reusability. In this study, heterogeneous solid base catalyst was prepared by impregnating the waste animal bone with different weight percent (wt%) KOH solution followed by drying and calcination at 900 °C for 3 hr. Having screened the catalytic performance and basicity of animal bone loaded with different K-compounds, 12 wt% KOH loaded on animal bone was chosen. The physico-chemical properties of animal bone, support and the KOH-impregnated calcined animal bone catalyst were characterized by means of titration (for basicity of catalyst), Fourier Transform Infra-Red (FT-IR) spectroscopy and X-Ray Diffraction (XRD) spectroscopy measurements. Thermogravimetric Analysis (TGA) was also performed for the selected catalyst. Catalytic performance of the catalyst was evaluated by transesterificating Jatropha oil with methanol in batch reactions. The Box-Behnken Design (BBD) of the Response Surface Methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst loading and methanol to oil molar ratio on Fatty Acid Methyl Ester (FAME) yield. Maximum yield of 96.74% was obtained at 11.56:1 methanol to oil molar ratio, 5.08 wt% catalyst loading, 64.05 oC reaction temperature and 500 rpm stirring speed in 3 hr reaction time. Reusability studies indicated that the prepared catalyst could be applied to at least three consecutive batches of the transesterification reaction without any significant loss of activity. The effects of temperature (313, 321.3, 329.6, and 338 K) and time (1, 2, 3, and 4 hr) at optimum conditions on the conversion of the oil into FAME were also investigated. The results obtained indicated pseudo-first order kinetics for the transesterification reaction using the prepared catalyst. The activation energy obtained was 38.55 KJ.mol-1. The physical, chemical and fuel properties of the produced FAME met the standard specifications.
Keywords: Animal bone, Heterogeneous catalyst, Potassium hydroxide, Jatropha oil, Transesterification