Free Fatty Acid Reduction of Palm Oil Mill Effluent (POME) Using Heterogeneous Acid Catalyst for Esterification

Abstract

In this study, Amberlyst-15 as heterogeneous catalyst was used for the reduction of free fatty acid (FFA) from the palm oil mill effluent (POME) for biodiesel production with acid-catalyzed esterification process. The objective of this study was to decrease a high FFA in POME to less than 2 wt.% FFA, for used as a raw material to produce biodiesel in the second-step transesterification process. Amberlyst-15 as an eco-friendly catalyst with non-toxic wastes after reactions, when compared to homogeneous catalysts such as sulfuric acid. Therefore, an esterification reaction with a heterogeneous acid catalyst was carried out to examine the FFA conversions. The conditions of two parameters of Amberlyst-15 catalyst (10–40 wt.%), and 1–8 h reaction time were varied, whereas the methanol to oil molar ratio and the speed of the stirrer were fixed at 5:1 and 300 rpm, respectively. As a result, the FFA sharply decreased from 89.16 wt.% to 1.75 wt.% under the conditions of 40 wt.% of Amberlyst-15, 5 h reaction time, 5:1 molar ratio methanol to oil, speed of the 300 rpm stirrer. The Amberlyst-15 had the potential to reduce high FFA in POME using the esterification reaction.