Valorization of banana pseudostem as a catalyst for transesterification process and its optimization studies

Concerns over the diminution of conventional fossil fuels have insisted on the development of alternative renewable sources such as biodiesel due to its sustainability, and minimal carbon emission characteristics. The present study discusses the production of Madhuca indica methyl esters (MIME) utilizing eco-friendly, renewable heterogeneous catalyst synthesized from the Poovan banana pseudostem (PBPS). Madhuca indica oil (MIO) used in the current study holds a high acid value of 21.7 ± 0.02 mg of KOH/g of oil. The acid-catalyzed esterification was performed followed by heterogeneous base–catalyzed transesterification process to reduce the acid value. The developed catalyst was characterized by energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. Furthermore, the transesterification parameters, i.e., catalyst loading, reaction time, and methanol to oil molar ratio, were investigated by performing seventeen predesigned experimental runs using response surface methodology (RSM) which determines the effect of the independent variables on the conversion of MIO to MIME. Numerical optimization tool revealed that the maximum conversion of 98.8% is accomplished at optimal reaction conditions of 5.9 wt% catalyst, 14.9 of methanol to oil molar ratio with the reaction time of 178.1 min. The outcome of this research supports that the indigenous catalyst developed via calcination of PBPS can be utilized as an environmentally benign and highly efficient solid catalyst for synthesis of biodiesel.