APPLICATION OF SIMULTANEOUS ADSORPTION AND TRANSESTERIFICATION PROCESS IN BIODIESEL PRODUCTION FROM USED COOKING OIL

In this work, the process of production of biodiesel from used cooking oil with a high-water content using simultaneous water adsorption onto bentonite and transesterification reactions was studied. The results showed that the process parameters studied, i.e., the water content of the used cooking oil, the amount of bentonite added and stirring speed, affect the yield of biodiesel. Simultaneous water adsorption and transesterification produced a higher yield than the conventional process (without bentonite addition). The highest biodiesel yield of 96.8% was obtained with the addition of 3 wt.% bentonite, a moisture content of 0.8 wt.%, and a stirring speed of 600 rpm. Scanning electron microscopy images showed that after the transesterification process, the bentonite surface was covered by absorbed materials. The Fourier transform infrared spectra confirmed the presence of various functional groups in the biodiesel, while gas chromatography-mass spectrometry analysis showed that the main component obtained in biodiesel is methyl palmitate. The properties of biodiesel showed that density, kinematic viscosity, and acid numbers met the Indonesian National Standard No. 7182:2015.