Synthesis and catalytic evaluation of hematite (α-Fe₂O₃) magnetic nanoparticles from iron sand for waste cooking oil conversion to produce biodiesel through esterification-transesterification method

Indonesia's catalyst needs to reach 2000 tons/year with active period of 1 up to 2 years. The catalyst requirement is largely filled with import catalysts. Iron sand has a potential to be used as a catalyst mainly because of the hematite magnetic mineral content (α-Fe₂O₃). α-Fe₂O₃ can be synthesized from iron sand using coprecipitation and calcination method. Performance of these synthesized catalyst evaluated through the production of biodiesel from waste cooking oil by esterification-transesterification method. The catalyst preparation by chemical coprecipitation method followed with calcination. Catalyst was characterized by using XRD, SEM-EDX, BET, and PSA and tested for biodiesel production. α-Fe₂O₃ phase was obtained at calcination temperature 650°C, 700°C, 750°C and 800°C. The best character is given at temperature 700°C. Biodiesel obtained meets SNI (Standar Nasional Indonesia) based on density, viscosity, and acid number. Yield of biodiesel obtained by using α-Fe₂O₃ calcined at 700°C reaches 86.781% while Fatty Acid Methyl Ester (FAME) content obtained reaches 87.880%.