Heterogeneous photo-Fenton degradation of polyacrylamide in aqueous solution over Fe(III)-SiO2 catalyst

This article presents preparation, characterization and evaluation of heterogeneous Fe(III)-SiO2 catalysts for the photo-Fenton degradation of polyacrylamide (PAM) in aqueous solution. Fe(III)-SiO2 catalysts are prepared by impregnation method with two iron salts as precursors, namely Fe(NO3)3 and FeSO4, and are characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. The irradiated Fe(III)-SiO2 is complexed with 1,10-phenanthroline, then is measured by UV-vis-diffuse reflectance spectroscopy (UV-vis-DRS) and XPS to confirm the oxidation state of Fe in solid state. By investigating the photo-Fenton degradation of PAM in aqueous solution, the results indicate that Fe(III)-SiO2 catalysts exhibit an excellent photocatalytic activity in the degradation of PAM. Moreover, the precursor species and the OH−/Fe mole ratio affect the photocatalytic activity of Fe(III)-SiO2 catalysts to a certain extent. Finally, the amount of Fe ions leaching from the Fe(III)-SiO2 catalysts is much low.