Elucidate three novel catalysts synthesized from animal bones for the production of biodiesel from ternary non-edible and edible oil blend: A case of Jatropha curcus, Hevea brasiliensis, and Elaeis guineensis oil

Abstract

Abstract This study developed three activated CaO-based catalysts from chicken foot bone, catfish bone, and the mixed, employed for the synthesis of biodiesel from the blend of three (2 non-edible, 1 edible) vegetable oil. The catalysts were calcined at 1000 °C for 3\xa0h and were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and BET isothermal adsorption. The blend of oil was achieved through the API gravity ratio, while the blended oil with high acid value was reduced with a strong acid (H2SO4). Process optimization of the reaction conditions was carried out using Central Composite Rotatable Design (CCRD) in the esterification step, while Box Behnken Experimental Design (BBED) was used in the transesterification of the esterified oil to biodiesel. The qualities of the biodiesel were determined using AOAC method. Results showed the oil blend ratio produced biodiesels of low viscosity and density. Catalysts’ characterization showed the amount of CaO-based found through XRD analysis in the catalysts was 93.52%, 91.24%, and 99.84%, respectively. Acid esterification through experimental design by CCRD produced a low blend oil acid number of 1.27\xa0mg KOH/g oil. The maximum experimental biodiesel yields of 93.60, 92.47, and 97.12 (%wt.), but, the statistical optimization predicted values by BBED were 93.86, 92.7685, and 97.2566 (%wt.), which were validated as 93.5400, 91.87, and 96.88% (wt.), respectively, at the reaction time of 69.76\xa0min, the catalyst amount of 4.16\xa0g, the reaction temperature of 69.79 °C, and the CH3OH/OMR of 4.62:1. Catalyst regeneration and reusability showed that the derived catalyst has the potential to be reused in the 4th cycle. The qualities of the biodiesel were well within the limit recommended for biodiesel standard.