Diatomite supported by CaO/MgO nanocomposite as heterogeneous catalyst for biodiesel production from waste cooking oil

Abstract

Production of renewable, biodegradable, and non-toxic biodiesel by recycling waste cooking oil offers a profitable way to reduce the raw materials of waste oil. Low-cost, efficient, reusable, and ecofriendly heterogeneous catalyst is therefore obligatory for the massive and industrial production of biodiesel from used cooking oil. Here, a novel basic heterogeneous catalyst was prepared from purified domestic diatomite supported by CaO/MgO composite. Different characterization techniques confirmed the loading of diatomite as catalyst support by CaO and MgO. The catalyst casting by the porous structure of diatoms skeletons causing clear enhancing of the total porosity and surface area of the catalyst. The efficiency of diatomite@CaO/MgO catalyst for converting the waste cooking oil into biodiesel was studied for different times, reaction temperatures, oil/methanol ratios, catalyst dosages, and reusability for several cycles of oil conversion. The maximum obtained biodiesel yield reaches 96.47% after 120 min at 90 °C using 6 wt% catalyst and 1:15 oil: methanol ratio. The produced biodiesel matched the standard biodiesel according to ASTM D-6571 and EN 14214 international biodiesel standards. Diatoms skeletons/CaO/MgO composite is a promising basic heterogeneous catalyst for efficient, high throughput, and low-cost biodiesel production.