Biodiesel production from Azadirachta India-derived oil by electrolysis technique: Process optimization using response surface methodology (RSM)

Biodiesel production from non-edible seed oil of abundantly available wild Azadirachta India through novel electrolysis technique assisted (trans)esterification was studied at room temperature. The response surface methodology (RSM) based on the central composite design (CCD) was applied with a three-parameter-three-level to optimize the operating condition, including voltage (5-15 V/cm), time (1-3h), and methanol to oil molar ratio (5:1-20:1). Based on experimental design, a quadratic model was developed. The effects of each parameter on the biodiesel production yield were discussed. The experimental results and optimum condition of the additional independent experiments were in good agreement with the predicted results of the model. The highest biodiesel yield was 28% without catalyst and 80% using an acidic catalyst. The optimum condition was as follows: time of 2 h, voltage of 15 V/cm, methanol to oil molar of 20:1, THF to oil molar ratio of 10:1, NaCl weight of 1 wt%, 2 wt% distilled water based on the total weight of solution, room temperature and H2SO4 catalyst weight of 16 wt%. Overall, non-edible Azadirachta India seed oil appeared to be applicable feedstock for the future biodiesel industry. By sensitivity analysis of significant parameters, the electrolysis technique is highly recommended as an efficient method to industrialize biodiesel production at ambient temperature.