Synthesis of green biodiesel using heterogeneous catalyst derived from snail shells

Abstract A promising sustainable biofuel was successfully produced from waste frying oils using a calcium oxide (CaO) catalyst derived from Mourgueta snail shell waste, representing a renewable and low‐cost resource. The transesterification reaction was conducted at room temperature by varying the methanol to oil molar ratios (6.4:1, 7.7:1, 9:1, 10.25:1) and catalyst loading (0.5–3 wt%). Additionally, the effect of calcination temperature on catalytic activity was investigated at 700°C, 800°C, and 900°C. Under optimal conditions, specifically, 1.5 wt% catalyst calcined at 900°C with a methanol to oil molar ratio of 9:1, the high conversion efficiency of 99.8% was achieved. This reactivity highlights the effectiveness of the biogenic CaO as a solid base catalyst for biodiesel production. The fatty acid methyl ester (FAME) content of the biodiesel product was confirmed by FTIR, 1 H‐NMR, 13 C‐NMR, and GC–MS analyses. The identified methyl esters included key components such as methyl linolelaidate, methyl palmitate, methyl oleate, and methyl stearate, indicating a high‐quality biodiesel composition. These results demonstrate the viability of converting agro‐waste into efficient heterogeneous catalysts, contributing to green chemistry, waste valorization, and the advancement of sustainable biofuel technologies.