Geopolymer catalysts derived from palm oil mill ash for biodiesel production from Calophyllum inophyllum oil

Chemical Engineering has a decisive role in a circular economy based on abundantly available waste materials. Renewable catalysts synthesized from abundant palm oil mill bottom ash (POBA) were applied in the biodiesel (methyl ester) production from Calophyllum inophyllum (CI) oil. Two different geopolymer materials, NaSil-geo and KSil-geo, were synthesized, characterized, and tested in converting CI into biodiesel. It was found that KSil-geo is highly effective in the transesterification process of CI with methanol to produce biodiesel. The fatty acid methyl ester (FAME) yield was obtained at 97% under the conditions reaction of 2% catalyst loading, methanol to oil molar ratio of 12:1, reaction temperature of 65 degrees C, and the transesterification reaction time of 120 min and stirring rate of 400 rpm. The properties of biodiesel produced in the form of cetane number, flash point, kinematic viscosity, density, and the fatty acid methyl ester content were obtained at 54.2, of 134 degrees C, 4.4 mm(2)/s, 878 kg/m(3), 99.65%, respectively. The reusability tested of the catalyst verified that the synthesized catalyst could be reused up to 5 times. The physical and chemical properties of the biodiesel produced to meet the standard of biodiesel specifications ASTM D6751 and SNI 7182:2015.

Automated summary

Chemical Engineering plays a crucial role in the circular economy by utilizing abundant waste materials. In this study, renewable catalysts synthesized from palm oil mill bottom ash were used to produce biodiesel from Calophyllum inophyllum oil. The synthesized catalyst showed high effectiveness in the transesterification process, achieving a fatty acid methyl ester yield of 97%. The produced biodiesel met the specifications of ASTM D6751 and SNI 7182:2015, and the catalyst could be reused up to 5 times.