Biodiesel synthesis from oil palm empty fruit bunch biochar derived heterogeneous solid catalyst using 4-benzenediazonium sulfonate

Abstract

In this research, biomass from oil palm empty fruit bunch was used as the carbon precursor and sulfonated by 4-benzenediazonium sulfonate (4-BDS) to produce solid acid catalyst. The as-synthesized catalysts were characterized and the performances were tested in esterification of palm fatty acid distillate (PFAD) for biodiesel production. Scanning Electron Microscopy (SEM) showed that clear porous and rough carbon surface was successfully developed after calcination which favored the attachment of sulfonic groups. Thermogravimetric Analysis (TGA) result showed that the catalyst was thermally stable up to 600 °C. Fourier Transform Infrared Spectroscopy (FTIR) proved that SO and SO₃H sulfonic groups were successfully attached to the carbon catalyst. From the catalytic activity tests, the results showed that the catalyst which was calcined at 200 °C and sulfonated with 15:1 sulfanilic acid to AC ratio was the optimum catalyst as it provided the highest biodiesel yield. Further investigation showed that the reaction time of 7 h and 20 wt.% of catalyst loading were reported as optimum esterification conditions which provided the highest biodiesel yield at 98.1 %.

Keywords: 4-benzenediazonium sulfonate; Biodiesel; Oil palm empty fruit bunch; Palm fatty acid distillate; Solid acid catalyst.