Response surface optimization approach to predict the maximum %biodiesel yield via transesterification of esterified shea butter oil by utilizing bio-catalysts

Abstract

A two-stage optimization process was explored utilizing response surface methodology (RSM). The factors affecting the process includes %FFA of shea butter oil, reaction time (50–60min), ethanol (ROH), oil mole ratio: 3:1–5:1 (w/w) for esterification and 3:1–7:1 (w/w) for transesterification, catalyst loading: 1–2% (H 2 SO4, v/v) for esterification and 1.5–2.5% based on different catalysts for transesterification. The optimal operating conditions of esterification showed minimum %FFA of 0.98 were 4:1 ROH/oil ratio, 55 ​min, and 1.5% (v/v). Calcine unripe plantain peels (CUPP) produced a maximum %yield of biodiesel of 92% at 5:1(w/w) ROH/oil ratio, 50min and 2.5 ​g while calcine watermelon pod (CWMP) showed the %yield of biodiesel of as 91 ​at 3:1 (w/w) ROH/oil ratio, 55min and 2.5 ​g. However, the p-value of <0.0001 for each of the stages indicates that the models were significant with R2 of 0.9398 for CUPP and 0.9961 for CWMP respectively. Hence, utilizing CWMP catalyst is more accurate in terms of prediction and quality of biodiesel produced.