Rubber-Fe3O4@SiO2@H3PMo12O40 as heterogeneous catalyst for biodiesel production: Optimized by response surface methodology

The aim of this research is to develop magnetically recoverable Heteropoly acid (HPA) based catalyst (Rubber-Fe3O4@SiO2@H3PMo12O40) for biodiesel production. Magnetic Rubber powder with high dispensability, porosity and magnetism were prepared by co-precipitation method and covered by silica using TEOS to form Rubber-Fe3O4@SiO2. Finally, nanostructured catalyst was prepared by impregnation of phosphomolybdic acid (PMA). The proposed catalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spec-troscopy (FT-IR), Scanning Electron Microscopy (SEM) equipped with Dispersive Energy X-ray spectroscopy (EDS), Thermogravimetric analysis (TGA), The Brunauer-Emmett-Teller (BET) surface area analysis and vibrating sample magnetometer (VSM). The results showed the Keggin structure of the catalyst. The performance of the proposed core-shell nanocomposite to catalyze transesterification reaction was evaluated and optimized by response surface methodology (RSM). According to the results, 3w/w %, 3 h, 12:1 and 69 degrees C were found as optimum values for catalyst dosage, reaction time, molar ratio of methanol to oil and reaction temperature, respectively. The production yield was higher than 85% for four runs. At the fifth try, the catalyst performance was decreased slightly to 78.87%.

Automated summary

The aim of this research is to develop magnetically recoverable Heteropoly acid (HPA) based catalyst (Rubber-Fe3O4@SiO2@H3PMo12O40) for biodiesel production. The proposed catalyst, prepared by coating magnetic rubber powder with silica and impregnating it with phosphomolybdic acid, showed a Keggin structure. The performance of the catalyst in transesterification reaction was optimized, with the best conditions being 3w/w % catalyst dosage, 3 h reaction time, 12:1 molar ratio of methanol to oil, and 69 degrees C reaction temperature. The production yield was over 85% for four runs and slightly decreased to 78.87% on the fifth try.