Síntese, caracterização e aplicação de óxidos metálicos suportados em zircônia como catalisadores na produção de biodiesel

Abstract

Biodiesel is a renewable fuel produced by transesterification and esterification reactions. Using inexpensive feedstock and obtaining high conversions are important goals in the biodiesel production. Homogeneous and heterogeneous catalysis can be applied in the biodiesel reaction; nevertheless, one of the most issues encountered using homogeneous catalysis is the separation of the catalyst and product at the end of reaction. Heterogeneous zirconia supported metal oxide catalysts (ZnO/ZrO2, ZnONd2O3/ZrO2, ZnO-SiO2/ZrO2 e ZnO-SiO2-Nd2O3/ZrO2) were prepared via sol gel method and calcined at different temperatures (500°C, 525°C and 550°C). The synthesized catalysts were tested in batch and continuous (PBR) reactors and characterized using XRD, TGA, SEM-EDS and BET. The catalytic activity, water content, FAME content and leaching of metals were analyzed by potentiometric titration, coulometric titration, GCMS and ICP-OES, respectively. All of the compositions showed good catalytic activity; however, the best catalyst composition was ZnO-SiO2/ZrO2 calcined at 550ºC.