SYNTHESIS OF POTASSIUM/SiO2 CATALYST FROM LOCAL SOURCES AND TESTED BY TRANSESTERIFICATION OF CASTOR SEED OIL

Abstract

ABSTRACT There is a need for the utilization of locally sourced heterogenous catalysts for biodiesel production to curb the challenges associated with homogeneous catalysts. The aim of this study was to produce an active catalyst from ripe plantain peels and rice husk for biodiesel production. Locally sourced caustic potash from ripe plantain peels doped with Rice Husk; a heterogeneous solid catalyst, was made by wet impregnation at totally different preparation conditions: calcination of the RH before doping with KOH and doping the RH with KOH before calcination labelled catalysts A and B respectively. The properties of the catalysts were determined utilizing Brunauer-Emmett-Teller, Scanning electron microscopy, X-Ray Diffraction, Energy Dispersive X-ray, and Fourier TransformInfrared spectrum analysis. The Synthesised catalysts A and B were used for biodiesel production through Transesterification reaction of castor oil exploiting Response Surface Methodology, with three level-three factor randomised optimal design of temperature: 55oC to 65oC; catalyst loading: 2.0 to 3.0 wt/wt%; and time: 60 to 120 mins. The alcohol to oil proportion was kept constant at 6:1. Each of the catalysts showed chemical process activity, but catalyst B had a higher yield of 88.92 % biodiesel as compared to that of catalyst A of 77.76 % biodiesel. The kinetic study on the seed oil carried out at three different temperatures of 60, 61 and 62oC, showed a pseudo first order rate constant and rate law with a very high activation energy of about 36.03 KJ/mol. The reusability study carried out on the oil sample for 4 consecutive runs under the optimum conditions showed a slight decrease on the yield from 88.92 to 86.15 as the reaction progressed from the 1st run to the 4th run. Hence, it could be concluded that locally sourced caustic potash doped with Rice Husk catalyst has very high catalytic activity and is better than caustic potash from plantain peels alone.