Development of a nano alumina-zirconia composite catalyst as an active thin film in biodiesel production

Abstract

A nano-alumina-zirconia composite catalyst has been synthesized by a simple aqueous sol-gel method using AlCl₃.6H₂O and ZrCl₄ as precursors. Thermal decomposition of the precursor and subsequent formation of γ-Al₂O₃ and t-ZrO₂ have been investigated by thermal analysis. XRD analysis show that γ-Al₂O₃ and t-ZrO₂phases are formed at 700 °C. FT-IR analysis also indicate the phase transition to γ-Al₂O₃ occur in corroboration with X-ray studies. TEM analysis of the calcined powder reveal that spherical particles were in the range of 8-12 nm. The nano alumina-zirconia composite particles are mesoporous and uniformly distributed in their crystalline phase. In order to measure the catalytic activity, esterification reaction has been carried out. Biodiesel, as a renewable fuel, is formed in a continuous packed column reactor. Free fatty acid (FFA) is esterified with ethanol in a heterogeneous catalytic reactor. It is found that the synthesized γ-Al₂O₃/ZrO₂ composite has the potential to be used as a heterogeneous base catalyst for biodiesel production processes.