Modified ZnO to Indonesia limestone as heterogeneous catalysts for biodiesel production from Reutealis trisperma oil

The Bukit Jaddih Madura limestone has been modified as a heterogeneous catalyst in the transesterification reaction for biodiesel production. Limestone has been calcined at 900°C for 3 hours (CL) and it has been modified with ZnO using a wet impregnation method (ZnO/CL) to improve its catalytic activity. Catalysts were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), SEM-EDX, and basicity test. FTIR analysis showed that BKK and ZnO/CL were easily hydrated and carbonated. It was determined that CL and ZnO/CL catalysts contained CaO, MgO, and a little Ca(OH)2 from the XRD analysis. Next, from SEM analysis, we are able to observe that CL and ZnO/CL had different morphologies and sizes. Basicity test showed base strength of CL was 15,0 <H_ <18,4 and ZnO/CL was 8,2 <H_ <15,0. The catalyst activity on the transesterification reaction of Reutealis trisperma oil with methanol showed that biodiesel yield increased with increasing ZnO concentration.