Preparation of Fe-modified rice husk catalyst for oleic acid esterification

This work focuses on the preparation and characterization of a sustainable and cost-effective catalyst derived from rice husk for the esterification of oleic acid, a crucial step in biodiesel production. An agro-waste solid acid catalyst was prepared by modifying rice husk char with a structure-directing agent and various concentrations of Fe3+ ions. The prepared catalysts, namely RH, 0.02 M Fe-RH and 0.06 M Fe-RH were characterized using XRD, FESEM, EDX, and N2 adsorption-desorption isotherm analysis. The effects of Fe3+ impregnation on the catalytic performance were investigated using the esterification of oleic acid and methanol as the probe reaction. The catalysts produced exhibit a mesoporous structure, providing a large surface area and uniform pore size distribution, which enhance its catalytic activity. The findings revealed that the 0.06 M Fe-RH catalyst demonstrated markedly improved catalytic performance over unmodified RHA, achieving the highest oleic acid conversion rate of 75.01 ± 0.65%. This work demonstrates the potential of utilizing rice husk as a sustainable precursor for the synthesis of highly efficient biodiesel catalysts, contributing to both waste management and the development of a more sustainable energy future.