Energy Conversion and Management, Vol.171, 969-983, 2018
Economically viable production of biodiesel using a novel heterogeneous catalyst: Kinetic and thermodynamic investigations
Biodiesel was produced in laboratory in two consecutive steps i.e. esterification followed by transesterification using a novel heterogeneous base catalyst and Madhuca indica (Mahua) oil as a feedstock. Barium lanthanum oxide, a novel catalyst was synthesized by four different methods i.e., co-precipitation (BLOC), solid state (BLOS) and the citrate route or auto-combustion method (BLOA1 and BLOA2). The catalyst was characterized and the catalytic activity was measured by quantifying the FAME content of the biodiesel. It has been observed that BLOA1, BLOA2, and BLOC resemble with each other as they have the same phase with an identical structural formula of Ba2La2O5. This observed structural formula constituted the mixture of the perovskite and metal oxides. The BLOS sample had the structural formula of Ba10La2O13 which proved the extensive formation of individual metal oxides. Out of the samples, BLOA2 synthesized by citrate route was efficient in biodiesel production. The citrate route synthesis performed at pH 2.31 enriched the catalyst mixed metal oxide surface with free OH- groups, which ultimately avoided the formation of the carbonate species, produced biodiesel with 97.5% FAME conversion. Hence, Barium Lanthanum Mixed metal oxide prepared by citrate route in acidic medium is a potential catalyst for biodiesel production. The reaction mechanism followed first-order kinetics. The activation energy (E-A) was 34.44 kJ mol(-1) and the frequency factor (A) was 7.94 min(-1). The physicochemical properties of the synthesized Mahua oil methyl ester (MOME) were measured according to ASTM D 6751 and were found to be within the permissible range.