RESPONSE SURFACE METHODOLOGY (RSM) FOR GREEN ULTRASOUND-ASSISTED TRANS-ESTERIFICATION OF WASTE PALM COOKING OIL USING HETEROGENEOUS CATALYSTS FROM CALCINED DURIAN PEEL ASH

Waste cooking oil is abundant and a source of environmental pollution, even though it has great potential as a raw material for biodiesel. The ash of Durian peel waste contains metal oxides that have the potential as base catalysts. The purpose of this study was to optimize the production of environmentally friendly biodiesel from waste cooking oil with Durian peel ash as a catalyst with Response Surface Methodology (RSM). Synthesis of heterogeneous catalysts (K2O) of Durian peel ash through calcination with temperature variations of 400, 500, and 600 °C for 5 hours. The transesterification reaction was carried out under ultrasonic waves using a molar ratio of methanol and oil of 12:1 with variations in catalyst concentration of 1, 3, and 5% (w/w), reaction temperature of 65^oC. The optimal conditions for transesterification of waste cooking oil after RSM analysis were the calcined catalyst at 600°C, the concentration of catalyst of 3% w/w, with a yield of 96.24 %. The results of biodiesel, including density, viscosity, refractive index, acid number, saponification number, and iodine number, meet SNI 7182:2015 for biodiesel. The results of IR and GC-MS analysis of the main components of the methyl esters consist of methyl 9-octadecenoate (44.89%), methyl hexadecanoate (37.67%), methyl 9,12-octadecadienoate (12.02%), methyl octadecanoate (3.50%), and methyl tetradecanoate (1.14%). This study offers a green process utilizing Durian peel ash as a local waste.