Microwave-assisted transesterification for optimized biodiesel production from waste cooking oil using a heterogeneous base catalyst derived from

Biodiesel production from waste cooking oil (WCO) provides an environmentally friendly solution for reducing fossil fuel dependence while addressing improper oil disposal. This study contributes a targeted optimization strategy for biodiesel synthesis by integrating two specific research initiatives: (1) the application of microwave-assisted transesterification to accelerate reaction kinetics, and (2) the development of a heterogeneous CaO catalyst derived from Pila ampullacea shells with controlled particle-size variation. The effects of these initiatives were systematically evaluated by measuring biodiesel yield and fuel quality under nine treatment combinations of microwave power (80, 240, 400 W) and catalyst particle size (40–60, 60–100, <100 mesh). The measurements revealed that higher microwave power significantly improved reaction efficiency due to enhanced dielectric heating, while larger catalyst particles produced higher CaO crystallinity, contributing to increased catalytic activity. The optimal condition (400 W, 40–60 mesh) produced a biodiesel yield of 62.75%. Characterization results showed compliance with SNI 7182:2015 for density, viscosity, cetane number, and iodine value, while acid number and calorific value indicated the need for further refinement. Overall, the findings demonstrate that combining microwave energy with biomass-derived CaO catalysts can substantially enhance biodiesel production performance, while the measurement outcomes clarify the mechanisms responsible for yield and quality improvements. These results offer important implications for scalable, low-cost biodiesel technologies using waste-based resources.