A Facile Approach for the Synthesis of SrTiO 3 /g‐C 3 N 4 Photo‐catalyst and its Efficacy in Biodiesel Production

Abstract Visible light active photocatalysts have attracted a lot of interest due to their simple chemical workup and recyclability. In this study, the role of Strontium Titanate/graphitic Carbon Nitride composite (SrTiO 3 /g‐C 3 N 4 ) was investigated for the pretreatment of waste frying oil (WFO) to reduce high free fatty acids (FFAs) for biodiesel production. SrTiO 3 /g‐C 3 N 4 photo‐catalyst was synthesized through the facile refluxing method and its activity was also compared with simple graphitic carbon nitride (g‐C 3 N 4 ). Experimental results revealed that SrTiO 3 /g‐C 3 N 4 possesses higher efficiency as compared to g‐C 3 N 4 . Photo‐catalyst was characterized through SEM‐EDX, XRD and FT‐IR. Maximum conversion of FFAs (85 %) was achieved at 1 % catalyst dose, 800 rpm stirring speed, 3 : 1 methanol to oil ratio, and 4 hours of reaction time. Esterified WFO was converted to waste frying oil methyl esters (WFOME) by using CaO‐KOH heterogeneous catalyst. The maximum yield of WFOME was obtained at 1.25 % catalyst dose, 65 °C, 600 rpm, 2 h of reaction time, and 12 : 1 methanol to oil ratio. Physicochemical analysis of WFOME revealed that it is in accord with ASTM standards.