Application of samarium doped lanthanum nickel oxide perovskite nanocatalyst for biodiesel production

Abstract

The catalytic performance of the synthesized LaNiO3 (LNO) and LaSmNiO3 (L1-xSxNO) perovskite structures as novel efficient catalysts for the conversion of waste cooking oil (WCO) to biodiesel was evaluated. The synthesized heterogeneous catalysts of LNO and L1-xSxNO were characterized via Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), Brunauer, Emmett, and Teller (BET), inductively coupled plasma-optical emission spectrometer (ICP-OES), and Power X-ray diffraction (XRD). The crystal size of LNO was obtained to be around 31 nm at 2θ of 47.31° using Scherrer's equation. Catalysts characterization revealed that doping Sm with LNO (L0.9S0.1NO) enhanced the surface area from 7.71 to 15.75 m2/g, and thus may provide more active sites for transesterification reaction. Also, the Sm doping causes numerous oxygen vacancies in the structure of perovskite, improving the catalyst's ability to catalyze reactions. To determine the optimum conditions in the WCO transesterification process, the response surface methodology (RSM) based central composite design (CCD) was applied. The influences of key parameters including MeOH/WCO ratio (5–20 mol/mol), reaction duration (1–5 h), catalyst mass fraction (1–5 wt%), and reaction temperature (60–120 °C) were explored on the behavior of the reaction. It is inferred that the L0.9S0.1NO catalyst has excellent catalytic activity in converting WCO to biodiesel. The experimental and modeling sensitivity analysis indicated that the application of L0.9S0.1NO catalyst led to the WCO conversion of 95.14 % to biodiesel at MeOH/WCO ratio of 9.07, reaction duration of 3.02 h, catalyst mass fraction of 3.08 wt%, and reaction temperature of 80.07 °C.