Highly Active Calcium Oxide Derived from Scallop Shell for Used Cooking Oil Transesterification Reaction

Abstract

The liquid additive grinding method was used to improve the specific surface area (SSA) of calcium oxide (CaO) derived from scallop shells as a sustainable resource. Grinding was carried out using a planetary ball mill on a laboratory scale by stepwise addition of some polar and non-polar solvents to determine CaO grinding limit. The crystalline phase of CaO was determined by using X-ray Diffraction (XRD) and SSA was observed based on Brunauer, Emmet, and Teller (BET) method. The mechanism of grinding was obtained from the Scanning Electron Microscope (SEM). The SSA of CaO was increased in proportion to the amount of the liquid additive and grinding time up to 102 m2 g-1 while the CaO phase was retained even after the addition of liquid according to the spectra of Fourier Transform-Infrared (FT-IR). The high conversion of triglyceride from used cooking oil to fatty acid methyl esters (FAMEs) up to 99% was obtained within an hour at 65℃.