Synthesis of fatty acid methyl ester from palm oil (Elaeis guineensis) with Ky(MgCa)2xO3 as heterogeneous catalyst

► Eggshell waste was modified to produce efficient composite solid base catalyst used in transesterification. ► The modified catalyst showed good activity towards triglyceride conversion at moderate reaction conditions. ► FAME content of as high as 88% was achieved with 3 wt.% catalyst in 4h at a reaction temperature of 65°C. ► The preparation method is simple and produced well-developed catalyst pores that enhanced performance. ► The heterogeneous solid base catalyst is reusable and separates well from reaction mixture. Fatty acid methyl esters (FAME) were produced from palm oil using eggshell modified with magnesium and potassium nitrates to form a composite, low-cost heterogeneous catalyst for transesterification. The catalyst, prepared by the combination of impregnation/co-precipitation was calcined at 830°C for 4h. Transesterification was conducted at a constant temperature of 65°C in a batch reactor. Design of experiment (DOE) was used to optimize the reaction parameters, and the conditions that gave highest yield of FAME (85.8%) was 5.35 wt.% catalyst loading at 4.5h with 16:1 methanol/oil molar ratio. The results revealed that eggshell, a solid waste, can be utilized as low-cost catalyst after modification with magnesium and potassium nitrates for biodiesel production.