Inhibition effect of chlorine ion on hydroxyl radical generation in UV-H2O2 process

Satoshi Tsuneda, Y. Ishihara, M. Hamachi, A. Hirata

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    UV-H2O2 process is widely used as an advanced oxidation process (AOP) for the treatment of chlorine volatile organic compounds (CVOCs) such as dichloromethane (DCM) with strong oxidativity of hydroxyl radical generated from photolysis of H2O2. The result of DCM degradation rate at different initial concentrations in UV-H2O2 processes indicated the inhibition effect of produced chlorine ions on DCM oxidation processes, because the first-order degradation rate constant increased with lower initial concentrations. A spin trapping adduct of hydroxyl radical with 5,5-dimethyl-1-pyrroline-n-oxide (DMPO) was quantified by ESR spectrometer after UV irradiation in the presence ofdifferent amounts of chlorine ion, and as a result, the chlorine ion was found to act as a hydroxyl radical scavenger, which resulted in decreasing DCM degradation rate. An UV-H2O2 reactor equipped with ion exchangers for removing chlorine ion achieved higher DCM degradation rate than that without ion exchangers.

    Original languageEnglish
    Pages (from-to)33-38
    Number of pages6
    JournalWater Science and Technology
    Issue number11-12
    Publication statusPublished - 2002



    • Chlorine ion
    • DMPO radical spin trapping
    • ESR
    • Hydroxyl radical
    • Ion exchanger
    • UV-HO process

    ASJC Scopus subject areas

    • Water Science and Technology

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