Synthesis of Graphene Oxide Enriched Natural Kaolinite Clay and Its Application For Biodiesel Production

A heterogeneous catalyst is one type of catalyst which is very effective for biodiesel production; thus, in this study, a novel heterogeneous bifunctional catalyst was prepared by kaolinite clay obtained from Padang of West Sumatera and impregnated with graphene oxide and potassium hydroxide ( KOH ) for the simultaneous esterification and transesterification reactions of palm oil into biodiesel . For comparison, two other catalysts were also prepared. The first catalyst was the same clay which was heated at 450oC for 4 hours, and the second catalyst was the same clay which was impregnated with potassium hydroxide ( KOH ) only. The three catalysts were characterized using X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), and Fourier Transform Infra - Red (FTIR). XRF analysis showed that the clay sample’s main composition consisted of 54% silica, 35% alumina, and 7% hematite. The XRD analysis results showed that the most dominant crystal composition was quartz, kaolinite, and hematite. The analysis results using FTIR showed a change in intensity and shift in wave numbers indicating a cation exchange. The catalytic activity test was carried out with a ratio of oil and methanol 1:6, catalyst amount 5%, 60o C reaction temperature , and 4 hours of reaction time . The results showed that the catalytic activity of clays impregnated with graphene oxide and potassium hydroxide was better with a yield of 58% compared to clays without impregnation and other clays that were only impregnated with KOH under the yields of 0.8% and 0.4%, respectively