Catalyst Activity of Solid Acid Catalyst Derived From Agricultural Biomass for Biodiesel Production From Waste Cooking Oil

Abstract

Homogeneous alkali catalyst produces soap as a by-product and generates a large amount of wastewater. This study investigates the potential of three types of biomass namely oil palm frond, coconut shell and groundnut shell to be developed as a solid acid catalyst for transesterification of waste cooking oil into biodiesel. The synthesis of solid acid catalyst is conducted by incomplete carbonization of biomass followed by sulfonation using concentrated sulfuric acid to incorporate the sulfonic group in the carbon body. The porosity of prepared catalyst was characterized by adsorption/desorption technique and surface acidity was evaluated by means of back titration method. Coconut shell showed the highest acid density of 0.51 mmol/g followed by groundnut shell and oil palm frond with 0.16 mmol/g and 0.12 mmol/g respectively. The biodiesel production was carried out at reaction conditions of methanol-to-oil ratio 20:1, reaction temperature 60 ºC, reaction time 6 h and catalyst loading 6 wt%. The highest biodiesel conversion was achieved using a coconut shell as a catalyst with 86.5%, followed by groundnut shell and oil palm frond. The use of solid acid catalyst derived from biomass could explores new market value for waste material while minimizing the solid waste production and further reduces cost and energy consumption in biodiesel production