The Degradation Of Organic Pollutants By Heterogeneous Fenton System Under Visible Light

Fenton and photo-Fenton oxidation is one of the effective advanced oxidation process (AOP) for degradation of organic pollutants. The disadvantages of the homogeneous Fenton system, second pollution of Fe ion, low effective utility of light and the application range of pH <3, can be solved by the heterogeneous Fenton system. In this research, photo-Fenton heterogeneous oxidation systems which used as the photocatalysts to degrade orgnic pollutants under the visible light were studied.1. Iron ion supported on different camers as effective catalyst for heterogeneous oxidation was prepared. The adsorption and degradation capability for dyes were studied.2. Silica gel supported Fe(â…¡) (SiOFe) was prepared and used as an effective catalyst for heterogeneous degradation of SulfoRhodamine B (SRB) and 2,4-Dichlorophenol (DCP) under visible irradiation (λ>420nm). UV-Vis, IR spectroscopy, Fluorescence, total organic carbon (TOC) and ESR measurements were employed to analyse the photoreaction products. The decolorization of SRB could achive 100% and TOC removal 72.3% after 180min. The solid catalyst is stable for repeated application with little loss of activity.Based on the results of ESR and fluorescence measurements indicated that the oxidative process was predominated mainly by the·OH radical generated in the system.3. Fe³⁺ supported on NaY zeolite as effective catalyst for heterogeneous oxidation was prepared. Based on the result of ESR indicated that the oxidative process was predominated mainly by the·OH radical generated in the system.The results showed that RhB could be efficiently degraded by choosed RhB/FeY/H₂O₂ system under visible irradiation with 100% decolorization and 75.6% TOC removal after 270 min reaction. After reaction 150min DCP was degraded 81.0% at the choosed DCP/FeY/H₂O₂ system under visible irradiation. Michaelis-Meenten equation was used to indicate it Catalytic characteristic and the Catalytic constant K_cat was 2.28×10⁵ M^-1 min^-1.4. RhB could be efficiently decolored by choosed RhB/Mot-Fe/H₂O₂ system for 300 min irradiation, Toc removed rate was 85.2%. DCP was mineralized rate was 81.0% at the choosed DCP/FeY/H₂O₂ system under visible irradiation. The oxidative process was predominated mainly by the·OH radical generated in the system. This solid catalyst was stable for repeated application with little loss of activity and could be recycled.