Technoeconomic and environmental impact assessment of industrial scale biodiesel production process from algal oil using a reusable basic ionic liquid magnetic nanocatalyst

Abstract

A unique magnetically reusable basic ionic liquid nanocatalyst was designed to convert algal oil into biodiesel. The imidazolium-based basic ionic liquid (BIL) was immobilized onto the magnetic nanocomposite (Fe3O4-SiO2), resulting in Fe3O4-SiO2-BIL nanocatalyst with notable properties of large surface area (21.963 m2/g), high saturation magnetization (28.78 emu/g) and high thermal stability. The nanocatalyst effectively facilitated algal oil transesterification with 96.94 % biodiesel yield under methanol: oil ratio of 8.58:1 and a catalyst dosage of 4.59 % at 60.60 °C for 87.42 min. The transesterification reaction proceeded with pseudo-first-order kinetics, featuring a relatively low activation energy. The nanocatalyst showed excellent reusability for eight recycles. A techno-economic analysis demonstrated that industrial-scale biodiesel production from algal feedstock was economically viable with a minimum payback of 2.25 years. The environmental analysis revealed a low carbon footprint with the emission of 0.074 kg CO2 per kg of biodiesel produced. This research presents a sustainable approach for biodiesel production from algal feedstock facilitated by Fe3O4–SiO2–BIL nanocatalyst, offering both environmental and economic benefits.