Nanoscale Zero Valent Iron Catalyzed Free Radical Reactions Application

In the area of environmental governance, the prevention and control of water pollution is high frequent problems arising in recent years. Dye is a kind of complex composition and relative refractory organics in the factory during the production and use of exhaust haven high chroma and toxicity of wastewater, such emissions from wastewater be refractory wastewater;was one of the refractory industrial wastewater treatment in China.The experiment used liquid phase reduction preparation of nanometer zero-valent iron(n ZVI). The size of prepared particle is smaller(the ranges of size is from 20 to 50nm), and more uniform dispersion. In an acidic aqueous environment, dissolution of zero valent iron produces Fe2+, Fe2+reduces H2O2 in turn generate ·OH with strong oxidizing, it can oxidize most organic pollutants. with the strong oxidizing,·OH can dispose the wastewater of dye liquor under the normal temperature and pressure, microwave, ultraviolet and n ZVI reduces K2S2O8 to ·SO4-, use ·SO4-to dispose wastewater of dye liquor. In acidic aqueous solution corroding zero-valent iron generated Fe2+ what could active K2S2O8 to produceing ·SO4-.Rhodamine b(Rh B) solution for the development of the target object as wastewater treatment, initial p H value in wastewater was investigated, temperature,concentration of n ZVI and concentrations of H2O2, Rh B influence of initial concentration on its decolorization effect.The results are as follows,The system of n ZVI/ H2O2 disposes the initial concentration of 10 mg/L of Rh B optimum conditions for the temperature of 30 ℃, the p H to 2.0, dosage n ZVI be 0.8 g/L,hydrogen peroxide dosage be 1 mmol/L, After 10 minutes, Rh B degradation rate goes to be over 99.0%. Reaction kinetics consistent with quasi-one, apparent reaction rate. The constant k was 0.334 min-1(30℃).Microwave-assisted n ZVI/ H2O2 disposes initial concentration of 100 mg/L of Rh B. The microwave power is 400w; the optimal reaction conditions was under the p H to 2.0, the 0.4g/L of n ZVI, hydrogen peroxide dosage of 2 mmol/L, after 60 seconds, Rh B degradation rate goes to be over 96.5%. Reaction kinetics level consistent with the apparent reaction rate, The constant k is 6.7×10-2 s-1(400w).Under ultraviolet light, n ZVI/ H2O2 disposes initial concentration of 30 mg/L of Rh B.The optimum conditions is under the temperaturer of room(20℃); the p H to 2.0, the n ZVI dosage of 0.3 g/L, hydrogen peroxide vote increase the amount of 0.15 mmol / L, after 60 minutes, Rh B degradation rate goes to be over 92.0%. Consistent with a reaction kinetics,apparent reaction rate constant k is 5.3×10-2min-1(20℃).The system of n ZVI/ K2S2O8 disposes the initial concentration of 100 mg/L of Rh B, the results shows, the p H to 3.0, with added potassium per-sulfate n ZVI best molar ratio n(n ZVI):n(K2S2O8)=2.9:1, K2S2O8 with the Rh B The mass ratio m(K2S2O8):m(Rh B)=0.8.After 120 minutes, Rh B degradation rate goes to be over 50.0%. Consistent with a reaction kinetics, apparent reaction rate constant k was 4.85×10-3 min-1(100℃).