A cleaner process for biodiesel production from waste cooking oil using waste materials as a heterogeneous catalyst and its kinetic study.

Utilization of heterogeneous catalyst in the biodiesel production process can minimize the cost of separation process and subsequently reduce the biodiesel price. This study aims at developing a low-priced heterogeneous catalyst CaO/SiO 2 prepared from cheap and abundant wastes of eggshell and peat clay for the production of biodiesel from wasted cooking oil. CaO catalyst was capable to produce biodiesel with the yield of 78%. The presence of silica as a support generated from waste of peat clay improved the biodiesel yield to 91%. The optimum reaction time was 60 min and the biodiesel yield increased with temperature. A reaction mechanism during transesterification process was proposed based upon the characterization analysis. The mechanism suggested that the silica contributed in the esterification reaction and the CaO played a positive role in biodiesel production via transesterification. The kinetic study confirmed the proposed mechanism. The pre-exponential factor (A) and activation energy (Ea) were 5.44 × 10 8 min −1 and 66.27 kJ/mol. The proposed reaction mechanism and kinetic study lead to an essential step of biodiesel production for further research development or application at a larger scale. [ABSTRACT FROM AUTHOR]