Catalytic Fenton-like Oxidation Of Organic Dyes Over Fe-based Composite Oxides

Fenton technology is often researched on sewage treatment field（It can be used in pretreatment, intermediate processing or reprocessing）. It’s a kind of technology which can be widely used for sewage treatment and has high efficiency degradation. The reaction has some distinctive advantages of strong oxidizability, simple operation, mild condition and so on in catalytic degradation of organic pollutants such as the dye. However, the further application of traditional Fenton reaction is still limited by its narrow working p H range（p H 2-4） and low recovery of the catalyst. Therefore, it is highly desired to develop new heterogeneous Fenton catalysts with high activity and wide working p H range in the field of environmental catalysis. In this paper two kinds of nano-composite oxides were prepared and investigated as catalysts for catalytic degrade organic pollutants in water. The results are listed as follows:（1） Preparation and catalytic oxidation performance of Sodium Dodecyl Sulfate Modified Fe Co₂O₄As a heterogeneous Fenton catalyst, Fe Co₂O₄ was prepared by a simple co-precipitation method. The influence of sodium dodecyl sulfate（SDS） on the structure, surface charge, electron transfer ability and catalytic activity of Fe Co₂O₄ were investigated. Fe Co₂O₄-S prepared with SDS exhibited much higher catalytic activity for the degradation of methylene blue（MB） in aqueous solution than pure Fe Co₂O₄, which can be attributed to its higher electron transfer ability. The adsorbed SDS accelerated the reduction of surface Fe³⁺ to Fe²⁺ by H₂O₂ and ?O₂-. During the reaction the high-density Fe²⁺ on the surface of Fe Co₂O₄-S promoted the decomposition of H₂O₂ into ?OH which was the main active specie in the degradation of MB. Furthermore, SDS increased the adsorption capacity of the catalyst toward MB, thus facilitating the reaction between adsorbed MB and ?OH generated on the catalyst surface.（2） Preparation and catalytic oxidation performance of Fe/Ce O₂Fe/Ce O₂ was prepared by a simple co-precipitation method and investigated as a heterogeneous Fenton catalyst. The catalytic oxidation capacity of Fe/Ce O₂ for degrading the organic pollutants MB was also investigated. The results show that Fe-doped Ce O₂ improved the catalytic properties and promoted the catalytic ability in the degradation of MB ?O₂- was the main active specie. And 1% Fe/Ce O₂ prepared exhibited much higher catalytic activity for the degradation of methylene blue（MB） in solution than the catalysts of other proportion. The catalysis showed the best catalytic activity under neutral p H conditions.（3） Studies on the catalytic degradation of different pollutants by Fe Co₂O₄–SIn this chapter Fe Co₂O₄-S was investigated for the catalytic degradation of the organic pollutants. Three kinds of common organic dyes- naphthol blue black（NBB）, rhodamine B, methyl orange- are selected as the target pollutant. The results show that the catalyst prepared had the effect on degradation of the three organic dyes in some degree. And under the same conditions, the catalysts exhibited the highest activity for the degradation of NBB. We studied the effect of p H value, temperature, concentration of H₂O₂, cations and anions,typified by NBB. The results show that the optimal conditions of the reaction. When p H was 6.5, temperature was 40°C, the additive amount of H₂O₂ was 15 m L, the catalysts exhibited the highest catalytic activity. Adding cations and anions could also promote the reaction.