Nanocatalyst Mediated Biodiesel Production from Waste Lipid as Feedstock: A Review

Petroleum-based fuels are widely utilized and pose a threat to the environment, necessitating an urge to bring up an equally effective substitute. Globally, research is focused on biofuel production from various sources which is renewable, highly affordable, and has lesser carbon emission. Biomass is used as raw material to produce biodiesel to achieve clean, green, and renewable fuel. Edible and nonedible raw materials are utilized for the production of biodiesel. Biodiesel from lipid sources produced through the transesterification process serves as an effective alternative for the production of renewable fuel with reduced carbon emissions and greenhouse gases. The cost of biodiesel is dependent on raw materials and catalysts. The acidic and basic homogeneous catalysis reaction has a corrosive effect during synthesis and poses a risk in scalability. The heterogeneous reaction is costlier and has poor performance in the transesterification of lipids. Raw material contributes to 70–80% of the overall production cost. Municipal sewage sludge (MSS) is rich in lipid content and serves as promising raw material for biodiesel production. Nanocatalyst has superior activity in producing pure products with fewer side reactions. This paper reviews the lipid extraction techniques and biodiesel production from MSS using various nanocatalysts.