Effective utilization of azolla filiculoides for biodiesel generation using graphene oxide nano catalyst derived from agro-waste

Abstract

A circular bioeconomy is concerned with environmental sustainability and waste valorization. Utilization of leftovers and trashes while elevating the value of biomass through the cascade is receiving greater attention in recent years. Biomass is expected to play a significant role in fixing global alternative fuel ambitions. Azolla, a type of macroalgae which grows very quickly, is employed to develop a self-sustaining Azolla biorefinery model. Tannery effluents are treated using the phytoremediation approach, and the algal oil extracted from the cultivated Azolla is employed to produce bio-diesel as an alternative energy source. Biodiesel is produced via the transesterification technique. N2 sorption isotherms, scanning electron microscopy (SEM), FT-IR, and X-ray diffraction studies are used to evaluate the catalyst. The IR spectral analysis with the absorption bands corresponding to alkyl and ester stretching and bending modes of vibrations confirm biodiesel production. The reaction mechanism involved in the conversion process is proposed, and the process parameters such as the reaction temperature, oil-to-methanol molar ratio, and catalyst quantity are optimized. The results show that a catalyst loading of 2 % (by weight) and a molar ratio of 1:9 produce a high biodiesel yield with GO as the catalyst at temperatures between 60 and 65 °C. Its ability to catalyze allowed for numerous cycles of repetitive use. The results show that employing GO as a catalyst to trans esterify Azolla oil to biodiesel is cost-effective and reliable.