Biodiesel production from waste chicken oil using nanoeggshell heterogeneous catalyst with isopropyl ether as cosolvent

The main aim of the present work is to produce biodiesel from waste chicken fat using a nanoeggshell heterogeneous catalyst. For the first time, isopropyl ether was used as cosolvent and investigated the effects of transesterification factors affecting the biodiesel yield. The eggshell has been activated in the muffle furnace at 900 degrees C and was further characterized by using X-ray diffraction analysis, Fourier transform infrared spectrometer, thermogravimetric analysis, transmission electron microscopy, Brunauer-Emmett-Teller, and Hammet indicator to study the catalytic behavior of the catalyst. Optimization of transesterification parameters such as methanol-to-oil ratio, methanol-to-cosolvent ratio, catalyst concentration, and reaction time have been investigated using statistical techniques of response surface methodology (RSM) with a central composite design. The empirical value of methyl ester yield obtained from RSM (95.7%) could be comparable with the experimental value (98.1%) and showed that the model shall be considered statistically significant at 97% confidence level. Using Design expert software, by point prediction tool, the experiments were repeated for two times under optimal conditions attained biodiesel yield of 97.2%. The experimental work explored that the addition of isopropyl ether improved the biodiesel yield with a reduction in reaction time from 4 to 1.5 h. The catalyst reusability was stable up to four cycles of the transesterification reaction.