Synergistic tri-metallic Ca/Mg/Sr crab shell catalyst for transesterification: probing active site basicity

This study investigates the catalytic potential of crab body powder (CBP) derived from waste crab bodies for the conversion of triglycerides (TG) to fatty acid methyl esters (FAME). CBP is subjected to temperature treatments and characterized using various techniques. Its catalytic activity is compared to that of commercial materials such as CaO and MgO. The results demonstrate that the tri-metallic Ca/Mg/Sr catalyst derived from CBP heated at 900 °C (CBP900) exhibits the highest TG to FAME conversion rate of 96.8%. Interestingly, CaCO 3 heated to 900 °C shows comparable activity to CBP900. The enhanced catalytic performance is attributed to the presence of oxygenated surface functional groups, which enhance the basicity of the catalyst, as well as improved crystallinity, facilitated mass transport, and well-defined active sites within the CBP structure. These findings highlight the potential of waste-derived tri-metallic Ca/Mg/Sr CBP as a sustainable and efficient catalyst for biodiesel production. Further investigations are warranted to optimize reaction conditions and explore the underlying mechanisms, thereby opening avenues for utilizing waste biomass in renewable energy applications.