Evaluation of Shell-Derived Calcium Oxide Catalysts for the Production of Biodiesel Esters from Cooking Oils

Shruthi Perna,Beng Guat Ooi,Francis Uchenna Okejiri,Ngee Sing Chong,Saidi Abdulramoni

doi:10.32861/ajc.61.20.27

Abstract

Due to the high cost of feedstock and catalyst in biodiesel production, the viability of the biodiesel industry has been dependent on government subsidies or tax incentives. In order to reduce the cost of production, food wastes including eggshells and oyster shells have been used to prepare calcium oxide (CaO) catalysts for the transesterification reaction of biodiesel synthesis. The shells were calcined at 1000 °C for 4 hours to obtain CaO powders which were investigated as catalysts for the transesterification of waste cooking oil. The catalysts were characterized by Fourier Transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and X-ray fluorescence (XRF) spectroscopy. Reaction parameters such as methanol-to-oil molar ratio, CaO catalyst concentration, and reaction time were evaluated and optimized for the percentage conversion of cooking oil to biodiesel esters. The oyster-based CaO showed better catalytic activity when compared to the eggshell-based CaO under the same set of reaction conditions.

Highlights

The increase in global energy demand, diminishing fossil fuel reserves, awareness of climate change issues, and environmental pollution resulting from the excessive use of fossil fuels, have in the recent past triggered serious interest among researchers in investigating alternative energy sources which can supplement or substitute fossil fuels.Vegetable oils are mainly esters of fatty acids and glycerol, which can be converted to fatty acid methyl esters (FAME), known as biodiesel [1]
The shells were calcined at 1000 °C for 4 hours to obtain calcium oxide (CaO) powders which were investigated as catalysts for the transesterification of waste cooking oil
The catalysts were characterized by Fourier Transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD) and X-ray fluorescence (XRF) spectroscopy

Summary

Introduction

Vegetable oils are mainly esters of fatty acids and glycerol, which can be converted to fatty acid methyl esters (FAME), known as biodiesel [1]. Much attention has been focused in the last few decades on utilizing heterogeneous catalysts for biodiesel production instead of the homogenously catalyzed transesterification of vegetable oil. The high cost of production is mainly attributed to the high cost of feedstocks and catalyst consumption. Effective ways to reduce the cost of production involve the use animal fats or waste cooking oil (WCO) as feedstocks. The use of WCO as biodiesel feedstock is of interest to researchers because it utilizes waste products thereby eliminating the need for their disposal. Using alternative feedstock like WCO can effectively reduce the cost of raw material by 60 – 70 % [8]

Methods

Results

Discussion

Conclusion