Photoassisted Fenton-like degradation of polyacrylamide aqueous solutions using iron oxide/TiO2/Al2O3 heterogeneous catalysts

Iron oxide/TiO2/Al2O3 (ITAO) catalysts were prepared by the impregnation method using TiO2/Al2O3 as supports and characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction and X-ray photoelectron spectroscopy methods. The characterization results illustrate a rough surface of ITAO with a large BET surface area (150.89 m(2)/g). In addition, the impregnated Fe oxides were comprised with FeOOH and Fe2O3, which were evenly distributed on the supports. By investigating the photoassisted Fenton-like degradation of PAM in aqueous solution, the results indicate that the ITAO catalysts exhibited an excellent photocatalytic activity in the degradation and mineralization of PAM. Moreover, we also evaluated the effects of H2O2 on the catalytic activity and investigated the decomposition kinetics of H2O2 in the reaction process. The decomposition of H2O2 followed pseudo-first order kinetics in the heterogeneous photoassisted Fenton-like reaction with ITAO catalyst. The reactive intermediates generated in the UV + ITAO + H2O2 heterogeneous photo-Fenton system were detected through the method of fluorescence using coumarin as a radical trap, and the results indicated the generation of highly reactive hydroxyl radicals. Thus, it is indicated that the participation of the UV light in ITAO + H2O2 heterogeneous photo-Fenton system is very important for improving the center dot OH generation, which could benefit the decomposition of refractory organic compounds.