Synchronized Esterification and Transesterification of Jatropha Curcas Using Ferric Sulfate Modified Snail Shells As a Bi-Functional Catalyst: A Box-Behken Optimization Approach

Abstract

The study is focused on modelling and optimizing the process parameters on the production of biodiesel from Jatropha Curcas oil using achantinoidea shell catalyst. Shells of achantinoidea were sourced, crushed, sieved, and subject to temperatures of 900°C for 4 h to convert CaCO3 present to CaO and further doped with ferric sulfate. Characterization of the catalyst was conducted via Fourier transform infrared (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray fluorescence diffraction (XRF). Optimization was done using response surface methodology (RSM) based on the Box–Behken design. The parameters optimized in the production process are methanol to oil molar ratio, catalyst concentration, temperature, and time. A second order quadratic model (p < 0.0001) was developed for predicting the methyl-ester yield. The model predicted maximum yield of 84.74% under the following optimum process conditions: methanol to oil molar ratio 15 : 1, catalyst concentration 8.90 wt %, temperature 62.36 and reaction time 3 h, while for the acid value the model predicted minimum 1.11 under same conditions.