LAUSR

Abstract This study synthesizes a Na2ZnSiO4 phase as efficient and low-cost heterogeneous catalyst for biodiesel production. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) along with Energy Dispersive X-Ray Spectroscopy (EDS), Brunauer–Emmett–Teller (BET) surface area analysis isotherms are herein conducted to characterize the structure, texture, composition and surface area of the catalyst, respectively. A Box-Behnken design (BBD) is performed to screen out: the methanol: oil ratio (6:1 to 14:1), catalyst load (0.5 to 5.5 wt%) and stirring rate (500 to 800 RPM), affecting the transesterification reaction using commercial soybean oil as a triglyceride source while fixing the temperature reaction at 65 °C. The oil and its fatty acid methyl esters (FAME) are characterized using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance modulus (FT-IR-ATR). XRD and SEM confirm the successful synthesis of the monoclinic Na2ZnSiO4 phase with low traces of ZnO (  methanol: oil ratio > stirring rate. The FAME conversions drop to 48.4 and 62.42% after 5 cycles of continuous catalyst reuse, according to FT-IR-ATR and proton nuclear magnetic resonance (1H NMR) measurements, respectively.