Kinetics studies of sustainable biodiesel synthesis from Jatropha curcas oil by exploiting bio-waste derived CaO-based heterogeneous catalyst via microwave heating system as a green chemistry technique

•MW heating system as an environmentally benign technique was studied.•Calcined oyster shells can be utilized as eco-friendly and cost-effective catalysts.•Non-edible JCO is a promising feedstock for low-cost biodiesel production.•A biodiesel yield of 91.1% was attained under various optimized conditions.•Catalyzed transesterification reaction had activation energy (Ea) of 9.58 kJ/mol.