Synthesis of Pure and High Surface Area Sodalite Catalyst from Waste Industrial Brine and Coal Fly Ash for Conversion of Waste Cooking Oil (WCO) to Biodiesel

Abstract

The ravaging environmental menace of coal utilization in power generation and high cost of biodiesel production had recently resulted to global energy discourse. Non-waste-derived heterogeneous catalysts prepared from waste materials could reduce production cost of biodiesel and thus make it economical and environmentally sustainable. In this preliminary study, coal fly ash and industrial waste brine of South African origin were beneficiated for synthesis of waste-derived solid Hydroxy Sodalite (HSOD) catalyst. Non-waste-derived catalysts are not economical and environmentally sustainable. However, hydrothermal synthesis technique was employed to synthesize the catalysts used to produce biodiesel in a batch reactor. The physicochemical properties of the catalysts were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), Scanning electron microscopy equipped with Energy-dispersive X-ray spectroscopy (SEM-EDS). Textural property of the catalyst was obtained via nitrogen physisorption at 77 K. The catalyst was tested for producing biodiesel from waste cooking oil using these conditions: methanol-to-waste cooking oil ratio of 15:1, 3 wt % of catalysts, and agitation speed of 300-500 rpm, 8 h reaction time and temperature of 60 o C. The biodiesel yield for waste-derived catalyst and non-waste-derived catalyst were 89.4 and 85.0 % respectively, at a maximum waste cooking oil conversion of 97.0 %. Results of the BET analysis reveal that the surface areas of waste-derived and non-waste derived catalysts were 33.05 m 2 g -1 and 0.1645 m 2 g -1 , respectively.