Synthesis of bentonite-supported Fe(II) and heteropolyacid (HPW) composite through a mechanochemical processing

Abstract In this work, a mechanochemical synthesis process was introduced as a facile method for producing bentonite-supported Fe(II) and heteropolyacid (HPW) composite, a catalyst used for photo-Fenton reaction and conventionally produced only by liquid-phase synthesis method. The composite was successfully synthesized under solid-phase condition in a ball mill through three stages of mechanical milling. The optimum synthesis conditions of composite were obtained, and the effects from the synthesis conditions on the catalytic activity of composite were discussed. The composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy disperse spectroscopy (EDS), fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The characterization results showed that the composite was a material with smooth surface, loose and clear layered structure, and had crystalline and amorphous phases in the microscopic scale. The characterization demonstrated the functional components of Fe(II) and HPW were successfully immobilized on the composite. Based on the characterization, the formation mechanism of composite in the mechanochemical synthesis was presented. The composite synthesized through the mechanochemical processing showed both high catalytic ability and excellent long-term stability in use. The results indicated that mechanochemical synthesis, as a green, simple and efficient preparation technology, was suitable for the industrial production of bentonite-supported Fe(II) and HPW composite.