Green hetero-alkali catalyst in optimized waste lard oil transesterification for biodiesel synthesis

Abstract

Climate change in addition to the imminent depletion of the fossil fuel reserve has necessitated the search for a sustainable alternative fuel. In this research, the catalytic capability of a green heterogeneous alkali catalyst, thermally activated banana-plantain-peel-ash catalyst was examined in optimized waste lard oil (WLO) transesterification process in lard-oil-methyl-ester (LOME) synthesis. The catalyst was derived from a banana-plantain-peel-ash mixture and subjected to a calcination process while the catalyst properties were described via Scanning electron microscope-Energy dispersive atomic-x-ray-spectroscopy (SEM-EDX), X-ray diffraction-(XRD), Fourier Transform Infra-Red (FTIR) as well as Brunauer-Emmett-Teller (BET). Optimization of the waste lard oil transesterification process was conducted with the Desirability Explore Algorithm (DEA) in Central Composite Design (CCD) of Response Surface Methodology (RSM). A 99.9 % conversion of WLO to LOME was attained at the optimum reaction settings of 57 °C temperature, catalyst amount-2.5 wt%, time-1.5 h, and methanol to WLO molar ratio of 10.5:1 with a total desirability of 0.99 which was evaluated experimentally as 99 %. In the LOME synthesis procedure, the resulting empirical model demonstrated statistical significance and suitability based on its high F-value of 35.59 and infinitesimal p-value of less than 0.0001. The determined LOME fuel qualities met the applicable standard specifications (ASTM-D6751 and EN-14241) hence, have the potential to function as a diesel fuel substitute. The fused influence of WLO and the thermally activated bio-mixture catalyst was highly effective in biodiesel synthesis. Thus; a promising cheap feedstock source for green and sustainable biodiesel production was achieved.