Characteristics and adsorption mechanism of Ion-exchange resin for biodiesel production

Abstract

Biodiesel is produced via transesterification process that involved reaction of triglycerides which is the major fatty acid content in crude palm oil (raw material) with methanol and producing Fatty acid Methyl Ester (FAME) and glycerol. The objectives of this study is to determine and optimize process variables for the biodiesel production using Response Surface Method based on Central Composite Design (RSM:CCD). The recomended optimization condition is temperature at 63.43 ºC, stirring speed at approximately 772.83 rpm, reaction time around 120 minutes and molar ratio of methanol : oil at 13:1. Under this operating condition, the model was predicted to get 90.17 % conversion of biodiesel. After demonstrating the suggested model, 89.23 % conversion of biodiesel was obtained experimentally and shows only 1.04% error to predicted conversion was obtained from the real experiments. Then, the suggested optimum process variables were applied for purification steps of biodiesel using DOWEXTM DR-G8 ion exchange resin. The effectiveness and physico-chemical characteristics of utilizing ion-exchange resin as adsorbent in biodiesel production system was been investigated by using Scanning Electron Microscopic (SEM) and Energy Dispersive X-ray (EDX). The investigation on determining the adsorption mechanism also been performed by fitting various kinetic and thermodynamic models determine the best-fit isotherm conditions. Langmuir adsorption isotherm model was founded to fit the adsorption mechanism of ion exchange resin due to highest correlation coefficient, R2 value which is at 0.986. As a conclusion, all the objectives of this study was achieved and shows that ion exchange resin is the best method for purifying crude biodiesel.