Catalytic Performance of Sodium Carbonate as a Heterogeneous Catalyst for Biodiesel Synthesis from Low-quality Feedstocks

Abstract

This study investigated the catalytic performance of sodium carbonate (soda ash) as a heterogeneous catalyst in the production of biodiesel from low quality feedstocks such as waste cooking oil and beef tallow. The focus was placed on its environmental advantages, cost efficiency, and overall effectiveness in operation. To support this, a series of experiments were carried out to identify the optimal reaction conditions (reaction time = 180 min, molar ratio = 1:6, temp = 65°C) needed to maximize biodiesel yield. Additionally, the mechanistic insights into the transesterification process catalyzed by soda ash are discussed, along with recent advancements and challenges in its application.  The findings revealed that soda ash has high purity and catalytic potential, achieving an optimal biodiesel yield of nearly 99% at 30 g catalyst loading. The catalyst showed good reusability, maintaining over 96% yield after three cycles, and FTIR analysis confirmed the presence of carbonate functional groups, which has a role as active sites. The produced biodiesel met most ASTM and EN standards, particularly for cetane number, density, acid value, although viscosity deviated from international limits. These results confirm sodium carbonate as a promising, low-cost, and sustainable catalyst, with further optimization required to meet global biodiesel quality standards.