Eco-green biodiesel production from domestic waste cooking oil by transesterification using LiOH into basic catalysts mixtures

Eco-green biodiesel is an alternative fuel produced by a sustainable methodology and using renewable sources as feedstock due to its green nature and lower emission of pollutants in comparison with conventional fuels. In this work, biodiesels were produced using an innovative source of catalysts, a mixture of metal hydroxides: lithium-sodium (LiOH + NaOH) or lithium-potassium (LiOH + KOH) due to the considerable increase in the consumption and disposal of Li-ion battery wastes (electronic residues) in recent years. Waste cooking oil samples from fast food chains and households were used as an oily raw feedstock without any prior treatment to produce eco-green biodiesel by a transesterification reaction at room temperature. The recycling process not only removes Li-ion battery wastes and oily contaminants from the environment but also enables the generation of a green power source. The presence of lithium as a catalyst for producing eco-green biodiesel was investigated in order to verify previously the possibility of using lithium recovered from waste Li-ion batteries present in electronic devices in general. As a result, nicely followed by hydrogen nuclear magnetic resonance, the biodiesel mean yield of 90% using 5wt. % LiOH with 95wt. % NaOH or KOH catalysts was obtained and considered to be relatively high considering the high resolution of this technique. Gas chromatography, thin-layer chromatography, hydrogen nuclear magnetic resonance, infrared spectroscopy, density, and viscosity were the techniques performed to analyze the chemical structure and physical properties of the biodiesel (methyl esters) produced samples in the presence of a lithium catalyst.