Treatment Of Ortho-Dichlorobenzene In Aqueous Solution By Homogenous Advanced Oxidation Processes

In this paper, ortho-dichlorobenzene, one of toxic and biorefractory halo organic compound, was chosen to study the degradation performance, kinetics and mechanism by homogeneous advanced oxidation process, H2O2/UV and O3/H2O2/UV. The following main results have been achieved:(1) A review about advanced oxidation processes and its appliance in water process has been written after consulting last conferences at home and abroad. At the same time, it points out that homogeneous advanced oxidation processes (H2O2/UV and O3/H2O2/UV) are effective methods to get rid of ortho-dichlorobenzene in water.(2) The degradation performance, influencing factors, reaction kinetics and mechanism of ortho-dichlorobenzene in the homogeneous advanced oxidation process was systematically studied in water. It was found that the ortho-dichlorobenzene could be degraded by the H2O2/UV process with the high reaction rate constant and mineralized completely, the oxidation degradation reaction accorded well with pseudo first order kinetics; 2,3-dichlorophenol, 3,4-dichlorophenol, 2-chlorophenol, formic acid, acetic acid and oxalic acid were identified as the main intermediates of ortho-dichlorobenzene. According to this, adopting GC/MS and ion chromatogram (IC) techniques, the pathways and mechanisms of UV/H2O2 photo catalytic degradation of ortho-dichlorobenzene were deduced.(3) After the similar experiments, it was found that the ortho-dichlorobenzene could be degraded by the O3/H2O2/UV process with the high reaction rate constant and mineralized completely too, the oxidation degradation reaction performance, kinetics, mechanism and intermediates were in the similitude of the H2O2/UV process. However, more carbonyl compounds were produced during degradation by the O3/H2O2/UV process because the ozone exists in reaction environments, and it need more time to mineralize ortho-dichlorobenzene completely.(4) The ions of formic acid, acetic acid, oxalic acid and Cl- that were produced during photo catalytic degradation process were quantitatively identified in this study,so the rule of theirs concentration change was concluded.The results of this study are propitious to control or get rid of all organic micro pollutants in water, and enrich the theory of advanced oxidation process; at the same time, lay a foundation for the water deep process by the H2O2/UV and O3/H2O2/UV techniques.