O3/UV降解水中有机物机理研究

利用O₃/UV降解了水中的硝基苯、乙醇酸和乙酸. 在硝基苯的降解过程中,当加入对H₂O₂具有催化分解作用的MnO₂时,O₃/UV降解效率明显下降,TOC的去除率甚至比单独臭氧化还低,在相同条件下处理40 min后,O₃/UV、O₃和O₃/UV+MnO₂对溶液TOC的去除率分别为44%、41%和39%.该结果表明中间产物H₂O₂对O₃/UV降解效率的提高具有重要的作用. 另外,有机物本身对自由基链反应是否具有促进作用也直接影响着O₃/UV的降解效率,当目标有机物是对自由基链反应具有促进作用的乙醇酸时,O₃/UV降解效率较高,30 min后乙醇酸的去除率即达76%; 而当目标有机物是对自由基链反应具有抑制作用的乙酸时, O₃/UV对其几乎无降解能力.

Study on the Mechanism of Ozonation of Organic Combination with UV Radiation

Nitrobenzene, glycolic acid and acetic acid were selected to be degraded by O₃/UV. During the degradation of nitrobenzene by O₃/UV, addition of MnO₂, an effective catalyst to decompose H₂O₂ in water, decreased the degradation efficiency obviously, and the degradation efficiency of O₃/UV was even lower than that of ozonation alone, for example, the TOC removal rates of nitrobenzene by O₃/UV, O₃ and O₃/UV+MnO₂ were 44%, 41% and 39% in 40 minutes, respectively. These results demonstrate that intermediate H₂O₂ plays an important role in enhancement of degradation efficiency of O₃/UV. Furthermore, the characteristic of organic, which acts as promoter or inhibitor in the process of ozonation, also affects the degradation efficiency of O₃/UV directly, when glycolic acid, a promoter in ozonation, was degraded, the combination UV radiation with ozonation could remove it efficiency, the removal rate of glycolic acid reached 76% in 30 minutes; however, when acetic acid, an inhibitor in ozonation, was degraded by O₃/UV, the removal rate of acetic acid was very low, which was similar with that of ozonation alone.