Synthesis of environmental benign biodiesel from algal (Anabaena) oil using Ba2SiO4 as efficient green catalyst

Abstract

The current work demonstrates a simple solid-state method for producing barium silicate catalyst for transesterification of Anabaena oil. The designed Ba2SiO4 spinel catalyst was characterised by following techniques such as thermo gravimetric analysis (TGA-DSC), powder X ray diffraction (P-XRD), furrier transfer infrared spectroscopy (FT-IR), scanning electron microscopy and electron diffraction spectroscopy (SEM-EDX), BET-surface area analyser and Hammett indictor acid-base titration method. The optimum condition for achieving highest FAME conversion of 98.4 % was observed at 65 °C, 12:1 methanol to oil molar ratio at 4h of reaction time. The catalyst was also stable up to six cycles with 98.1 % FAME conversion. Fuel properties of synthesized biodiesel were also compared with the ASTM standard. Kinetics studies revealed that transesterification of Anabaena oil is compactable with pseudo first order model with comparable activation energy 36.48 kJ/mol. The reaction equilibrium constants were also studied in the temperature range of 45°–65 °C and the standard thermodynamic properties like ΔH# = 98.73 kJ mol−1, ΔG# = 23.53 kJ mol−1, ΔS# = 0.864 kJ mol−1 were obtained at 65 °C.