Assessing and optimizing the efficacy of synthesized CaO-based nano-catalysts for biodiesel production

Abstract

ABSTRACT The current research proposed the work on the consumption of waste cooking oil (WCO) as a valuable resource for the production of biodiesel. This study focuses on maximizing output yield by employing composite heterogeneous catalysts, namely calcinated calcium oxide with aluminum oxide (CaO/Al2O3) and calcium oxide with titanium oxide (CaO/TiO2). The calcination process was adopted for the catalysts at 600°C for 5 h to improve catalytic activities and to increase surface area. XRD and TGA were implemented to analyze the crystal structure and thermal stability of these heterogeneous catalysts. Experimentation was planned by implementing the response surface methodology (RSM) approach in combination with the Box-Behnken design. The optimum yield of fatty acid methyl esters (FAMEs) was experimentally observed at 96.56%, using CaO/Al2O3 at methanol to oil (m/o) molar ratio of 11.9:1, 3.19% catalyst loading, 53.79°C and 76.86 minutes (min). The maximum experimental yield with CaO/TiO2 was observed at 98.15% with the optimized operating conditions of independent process variables viz. m/o molar ratio 11:99, 2.53 wt.% catalyst loading and 68.14 min at 59.79°C. The research recommends the potential use of WCO and both the heterogeneous catalysts for optimal biodiesel yield; however, CaO/TiO2 exhibits superior performance over CaO/Al2O3, which is also confirmed by the XRD and TGA results.