Calcium-based catalyst prepared in the presence of biopolymer/biomass for biodiesel production: Elucidating their influence on the catalytic efficiency

This study investigates the influence of various biomass/biopolymers, namely pectin, cellulose, starch, chitosan, chitin, and shrimp exoskeleton, as modifiers in preparing calcium-based catalysts. The impact on the catalytic performance of the initial pH and type of biopolymer were examined. Significant differences in the material morphology, phase composition, and catalytic activity were found. The most efficient material was prepared with shrimp exoskeleton at pH 2, achieving a remarkable biodiesel yield of 100 % in just 3 h, with a catalyst loading of 1 wt% and a methanol-to-oil molar ratio of 7:1 at 65 °C. A possible explanation for the differences in the performance of the different materials prepared as a function of the biopolymer employed is given. Insights into the catalytic activity were derived from various characterization techniques, including FTIR, TGA, BET, CO₂-TPD, XRD, SEM, and EDS. This article presents the first comprehensive study on using different types of biopolymers as modifiers for synthesizing calcium-based catalysts. Our findings demonstrate that the nature of the biopolymer strongly influences catalytic activity, and the possible use of shrimp exoskeleton can be highlighted as a sustainable strategy for preparing highly active catalysts.