Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman Economically viable production of biodiesel using a novel heterogeneous catalyst: Kinetic and thermodynamic investigations Shalini Sahani, Yogesh Chandra Sharma ⁎ Department of Chemistry, Indian Institute of Technology (BHU) Varanasi, 221005, India ARTICLE INFO Keywords: Citrate route Auto-combustion Heterogeneous FAME Feedstock ABSTRACT 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 Ba 2 La 2 O 5 . This observed structural formula constituted the mixture of the perovskite and metal oxides. The BLOS sample had the structural formula of Ba 10 La 2 O 13 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 physico- chemical 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. 1. Introduction In the current scenario, biodiesel has been evinced as a renewable alternative of petro diesel which is depleting day by day and will be exhausted in future [1]. Transesterification is the most suitable and frequently employed technique for biodiesel production at large scale [2]. In this direction, the prime focus of researchers is constricted to leverage natural resources for biodiesel production at minimum cost without competing with food security. The important issues for bio- diesel production through transesterification are availability of feed- stock, alcohol, and catalyst [3,4]. As edible oils are scarce in India, non edible oils must be consumed in lieu of edible oil to fulfill the re- quirement of feedstock during transesterification [5]. Non-edible oil plants are well adapted to arid, semi-arid conditions and require low fertility land and low moisture demand to grow [6,7]. The cost of cultivation gets lowered down because these plants can reasonably be suitable for high yield without any intensive care [8]. Though avail- ability of non-edible oil may be proved as a critical issue, this proble- matic situation can be tackled out by exploring high lipid content non- edible feedstocks. In the present study, Madhuca indica (Mahua) oil has been employed as a non-edible feedstock for biodiesel production. Predominantly, this feedstock is indigenous to the Indian subcontinent and South Asia as well. Puhan et al. [9] reported 180,000 tons annual production of Mahua oil in India. It may be a green substitute for conventionally utilized vegetable oils for biodiesel production. The heterogeneous basic catalyst brings about robustness in trans- esterification reaction for biodiesel production overweighing acid cat- alyst [10]. Recently, extensive application of metal oxides as the het- erogeneous catalyst has led to the development of different chemical synthesis routes for their production [11]. Extensively adopted methods for the wide-scale production of catalyst material belong to bottom-up synthesis approach including co-precipitation, the sol-gel method, auto- combustion method micro-emulsion method, hydrothermal, spray pyrolysis, reverse micelle and solid state[11]. Among them, chemical co-precipitation method is the widely adopted method to synthesize various metal oxides. It incorporates several characteristics in metal oxide powders with some modification such as a change in temperature of mother liquor, agitation rate, and https://doi.org/10.1016/j.enconman.2018.06.059 Received 2 April 2018; Received in revised form 15 June 2018; Accepted 16 June 2018 ⁎ Corresponding author. Tel.: +91 2570001; fax: +91 542 2304728. E-mail address: ysharma.apc@itbhu.ac.in (Y.C. Sharma). Energy Conversion and Management 171 (2018) 969–983 0196-8904/ © 2018 Elsevier Ltd. All rights reserved. T