A Study On The Visible Photocatalytic Property Of Homogeneous And Heterogeneous Fenton-like Systems With PW₁₁O₃₉Fe????H₂O?^4-

Traditional photo-Fenton system constituted by the Fe³⁺/H₂O₂/UV. The system can the d egradation and mineralization of organic pollutants in water and does not cause secondary po llution problems. In particular, it can take advantage of the inexhaustible solar energy. It i s one of the most promising advanced oxidation technologies. However, the system has low p H values?? 3.0?, catalyst separation and defects can only absorb UV light, which limits its pr actical application. In order to overcome these disadvantages. In this paper, the absence o f Keggin-type heteropoly anion PW₁₁O₃₉⁷-( PW₁₁)as ligand can be synthesized in a wide p H range? 2⁸? are stable in Keggin type ofiron substituted heteropolyanions PW₁₁O₃₉Fe????H₂O? 4-(PW₁₁Fe).Application of sol- gel preparation of binary compound catalysts of PW₁₁Fe-SiO₂ and three-way catalysts of PW₁₁Fe-TiO₂-SiO₂, by IR, UV- Vis spectroscop y, cyclic voltammetry, scanning electron microscopy and X- ray diffraction characterization.They constituted a homogeneous and heterophase system of liking fenton and used an o rganic dye pollutants of Rhodamine B? Rh B? visible photocatalyticdegradation as a probe t o assess their performance. Experiments show that, in a homogeneous systemof [Rh B]=0.01mmol·L-1,[H₂O₂] =4 mmol·L-1 and [PW₁₁Fe]=0.6 mmol·L-1,the degradation rate of 100%after light cure for 60 mins and mineralization rate of 48% after light cure for 120 mins.In the PW₁₁Fe-SiO₂ heterogeneous system, the photo catalytic activity of the catalystsdecre ased significantly, the degradation rate of 76% after light cure for 180 mins and mineraliz ation rate of 25% after light cure for 240 mins. However, the Increaseing of TiO₂ compon ents can obviously improve the photo catalytic activity of catalyst in the PW₁₁Fe-TiO₂-SiO₂ heterogeneous system, the degradation rate of 100% after light cure for 180 mins and mi neralization rate of 74% after light cure for 180 mins. The hydroxyl free radical quenchin g experiments and Electron Paramagnetic Resonance? EPR? show that, Whether a homoge neous system, or is it the heterogeneous system,produced hydroxyl radicals in the presence o f visible light. Therefore, PW₁₁ Fe as a component of photo catalytic activity, can produced h ydroxyl radicalsled to the degradation and mineralization of organic matter. Rh B cyclic degr adation experiments show that the reused for 10 times, the PW₁₁Fe-SiO₂ and PW₁₁Fe-TiO₂-SiO₂ of the films' photo catalytic activity and almost no losses.