| The physical chemistry properties of ozone and the application of ozonation and ozone-based advanced oxidation processes (AOPS-O3) in water treatment are reviewed. In order to promote Ti(IV)-catalyzed H2O2/O3(Ti(IV)/O3/H2O2) process to the application of pretreating the real industrial wastewater, the contents of this thesis was mainly about the effect of inorganic ions on the removal rates of organics (acetic acid and acetophenone) by Ti(IV)/O3/H2O2process, and its pretreatment efficiency for an acid chemical wastewater was also discussed.Firstly of all, the effect of inorganic anion on acetic acid (HAc) removal was studied in the initial pH range of1.0to6.0. The results indicated that adding Ti(IV) to solution could greatly improve the removal rate of HAc by O3/H2O2in the initial pH range of1.0to5.5. Both NO3-and SO42-had no negative effect on the oxidative efficiency of Ti(Ⅳ)/O3/H2O2process in the initial pH range of1.0to6.0..In the initial pH range of1.0to4.0, the presence of Cl-significantly lowered the removal rate of HAc. However, the negative effect of Cl-was negligible in the initial pH range of4.5to5.5. A kinetic model was established in the presence of Cl-to describe the effect of Cl-in this process. And in the initial pH range of4.5to5.5, the presence of H2PO4-could improve the efficiency of Ti(IV)/O3/H2O2owing to its buffer action. Adding sodium carbonate had no effluence on the removal rate of HAc by Ti(Ⅳ)/O3/H2O2process in the initial pH range4.5to5.5, but the presence of Br-could result into a great reduce in the removal rate of HAc. The above results promote the application of Ti(IV)/H2O2/O3process in the pretreatment of the real industrial effluents.Secondly, the acetophenone was degraded by Ti(IV)/O3/H2O2and the effects of some common inorganic ions were also investigated at the initial pH value of2.8. It was found that the COD removal rates of acetophenone by ozone alone and Ti(IV)/O3/H2O2process were reduced in the presence of higher concentrations of Cl", but that the removal rates of acetophenone were similar in the absence or presence of Cl", indicating that the negative role of Cl-is its competing reaction with hydroxyl radical. The presence of H2PO4-would not affect the COD removal rates of acetophenone because the pH in solution was not obvious change during the oxidation reaction at pH2.8. The COD removal rates of acetophenone enhanced with the increased concentrations of Fe2+and the maximum COD removal rate was reached when1.4mg-L-1Ca2+was added to the solution by ozone alone. Under the same experimental conditions, the maximum COD removal rate was when1.4mg·L-1Ca2+or2.8mg·L-1Fe2+was added to the solution.Finally, the pretreatment efficiency of Ti(Ⅳ)/O3/H2O2for an acid chemical wastewater was investigated, and the process parameters were also optimized. The results showed that Ti(Ⅳ) could improve the oxidative efficiency of O3/H2O2greatly. When the concentrations of Ti(Ⅳ) and H2O2were20mg·L-1and900mg·L-1, Ti(Ⅳ)/O3/H2O2system had the highest oxidative efficiency and also could remove the chroma of the wastewater completely. Ion chromatography analysis showed that some small molecular organic acids were generated, and that the concentrations of Cl-and NO3-in the solution increased, indicating the degradation of original organic compounds in wastewater. After the pretreatment at the initial pH of5.0, the BOD5/COD value of waste water increased from0.05to0.332. The above results indicate that the function of Ti(Ⅳ)/O3/H2O2process for the pretreating refractory acid wastewater is excellent. |
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