River snail shell as a highly effective renewable heterogeneous base catalyst for the production of biodiesel

Abstract

The biodiesel manufacturing process favors heterogeneous catalysts over homogeneous catalysts. The main drawbacks of using homogeneous catalysts are their non-renewable nature, separation, and washing, which can be avoided by using heterogeneous catalysts. This research looks into the shell of a river snail (Viviparidae) that has been improved with modified activated carbon (MAC) as a heterogeneous solid base catalyst for palm oil transesterification. The waste shell was repeatedly washed to remove any organic impurities attached to it and then dried in an oven. It was calcined in an air atmosphere for 2 h at a high temperature of 900 °C. The calcined sample (calcium oxide: CaO) was powdered and mixed with MAC. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and the Brunauer-Emmet-Teller (BET) method were used to characterize the CaO/MAC (mass fraction 3:1) catalyst. In order to optimize the reaction conditions for biodiesel production, operating parameters such as methanol to oil mole ratio, catalyst amount, reaction time, and microwave electrical power were investigated. As a result, the best reaction parameters were discovered to be 12:1 methanol to oil mole ratio, 2.5 wt.% CaO/MAC based on oil weight, 4 min of reaction time, and 600 W microwave electrical power. After being reused five times, the biodiesel yield could still reach 90%, indicating that the novel catalyst had good stability and recyclability. The biodiesel fuel properties obtained in this study were compared to the international biodiesel standards ASTM D6751 and EN14214. River snail shell can be thought of as a nature-based benign and resourceful material for biodiesel production, opening up a new path for fuel sustainability.