| The physical chemistry properties of ozone and its application in water treatment are reviewed, and the emphasis of discussion is put on metal catalytic ozonation technology developing recently. On the basis of the present research situation of ozonation in water treatment and its existing shortcomings, the research target and main task of this work were proposed. The contents of this paper mainly include three parts: kinetic and mechanism of ozonation of terephthalic acid; Fe2+/Fe3+ homogeneous catalytic ozonation of phenol; a quantitative study on the mechanism of Mn2+ catalytic ozonation of oxalic acid. The above results are of significance for the practical application of ozonation technologies in water or wastewater treatment, especially for the development of catalytic ozonation process.In chapterⅣ, the effect of ozonation of terephthalic acid (TA) was evaluated, and the kinetic and mechanism of this process were also discussed. The rate constants of TA with ozone and OH radical calculatedby the relative method were (0.047±0.010) L·mol-1·s-1 and 2.28×109 L·mol-1·s-1,respectively. The above results agreed very well with the apparent reaction rate constant of ozonation of TA when the process was controlled by chemical reaction. Intermediates during ozonation detected by high-performance liquid chromatography and ion chromatography included benzoic acid, tartaric acid, formic acid and oxalic acid. Therefore, the possible destruction pathway of ozonation of TA was proposed on the basis of above results.In chapterⅤ, the results showed that the direct reactions between phenol(or C6H5O-) and ozone were the main causes for degradation of phenol. Both Fe2+ and Fe3+ could improve the degradation efficiency of ozonation of phenol, and Fe2+ had higher activity than Fe3+. The possible mechanism of Fe2+ homogeneous catalytic ozonation of phenol included two reasons: formation of O3/H2O2 system and Fenton system during ozonation. In ozonation of aromatic compound, the intermdiate H2O2 would be produced, then resulting in improving the removal of phenol. Being analyzed and calculated, the Rct values of different systems is : O3/ Fe2+>O3/Fe3+>O3, which was in accordance with their degradation efficiencies of phenol.In chapterⅥ, oxalic acid was degraded by Mn2+ catalytic ozonation, and its kinetic mechanism was discussed by a quantitative analysis. The experimental results demonstrated that the ozonation efficiency increased with adding Mn2+catalyst to oxalic acid solution, and that Rct of ozonation system also increased. The degradation of oxalic acid by Mn2+ catalytic ozonation included three parts: direct ozonation; oxidation reaction of hydroxyl radical produced from the decomposition of the dissolved ozone; oxidation reaction of Mn4+and Mn7+. The pH of solution not only influenced the degradation efficiency of Mn2+/O3, but also determined the contributing proportions of three different oxidation reactions. When the pH was 2.9, the apparent rate constant of degradation of oxalic acid by Mn2+/O3 was 28.280×10-4 s-1, and the contributing proportion of three oxidation reactions was fO3:fOH:frest =2.1:19.0:78.9 ,respectively.However, when the pH were 5.3, 8.0 and 10.0, the apparent rate constant were 1.597×10-4 s-1, 1.535×10-4 s-1 and 1.545×10-4 s-1, and the contributing proportion of the three-oxidation reactions were fO3:fOH:frest=24.9:28.4:46.7, fO3:fOH:frest=23.6:54.5:21.9 and fO3:fOH:frest=19.6:74.4:6.0, respectively.
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