Clean and efficient production of biodiesel using barium cerate as a heterogeneous catalyst for the biodiesel production; kinetics and thermodynamic study

Abstract

Barium cerate, a novel solid base catalyst was employed in transesterification reaction for biodiesel production. The catalyst was characterized by Thermogravimetric analyses, powder X-ray Diffraction, Scanning Electron Microscopy attached with energy dispersive unit, Fourier Transform Infrared Spectroscopy. Karanja oil was used as non-edible feedstock for biodiesel production. The fatty acid profile of feedstock was analyzed by Gas Chromatography-Mass Spectrometry. In the present study, calcination temperature was optimized for synthesis of perovskite barium cerate with highest phase purity. Additionally, various Ba/Ce stoichiometric ratios were also checked to evaluate the active metal phase of catalyst. Ultimately, perovskite structure with 1:1 Ba/Ce was found to be most efficient one to catalyze the transesterification. This owed to the higher basicity value as well as compact and well-arranged perovskite crystal system which facilitate the catalysis on its surface. It produced the karanja oil methyl ester with 98.4% conversion at following experimental conditions: catalyst dose (1.2 wt %), oil to methanol molar ratio (1:19), reaction temperature (65 °C), reaction time (100min), and agitation speed (600 rpm). The pseudo-first order kinetic model was also successfully established for transesterification reaction. Green chemistry metrics (E-factor) and turn over frequency were also evaluated for methanolysis reaction. Barium cerate exhibited sixth cycle reusability with 81% methyl ester conversion. Therefore the prepared catalyst was ascertained as a sustainable heterogeneous catalyst for transesterification reaction. The physicochemical properties of the synthesized karanja oil methyl ester were measured according to ASTM D 6751 and were found to be within the permissible range. It ensured the compatibility of produced biodiesel with existing CI engines without any further modification. © 2019 Elsevier Ltd