Optimization of acid catalyzed esterification and mixed metal oxide catalyzed transesterification for biodiesel production from Moringa oleifera oil

Abstract

Abstract Moringa oleifera oil (MOO), a second-generation lipid feedstock that has been reckoned as a promising feedstock for biodiesel production in recent years. In the current study, crude MOO possessing high acid value (80.5 mg of KOH/g) was subjected to two step esterification and transesterification process for biodiesel production and the process was applied with central composite design (CCD) based response surface methodology (RSM). The results showed that H2SO4 concentration of 0.85 vol%, reaction time of 70.20 min, and methanol to oil ratio of 1:1 (vol/vol) significantly decreased the acid value to 3.10 mg of KOH/g of oil. Moreover, copper oxide-calcium oxide (CuO-CaO) nanoparticles were developed and evaluated as a novel heterogeneous base catalyst for synthesizing Moringa oleifera methyl esters (MOME). The synthesized catalyst was scrutinized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX) analysis. Copper oxide (CuO) was perceived to be the dominant phase in the synthesized catalyst. Highest MOME conversion of 95.24% was achieved using 4 wt% CuO-CaO loading, 0.3:1 (vol/vol) methanol to oil ratio and 150 min reaction time as the optimal process conditions.