Characteristics and fate of natural organic matter during UV oxidation processes

Yongtae Ahn, Doorae Lee, Minhwan Kwon, Il hwan Choi, Seong Nam Nam, Joon Wun Kang

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24 Citations (Scopus)

Abstract

Advanced oxidation processes (AOPs) are widely used in water treatments. During oxidation processes, natural organic matter (NOM) is modified and broken down into smaller compounds that affect the characteristics of the oxidized NOM by AOPs. In this study, NOM was characterized and monitored in the UV/hydrogen peroxide (H2O2) and UV/persulfate (PS) processes using a liquid chromatography–organic carbon detector (LC-OCD) technique, and a combination of excitation–emission matrices (EEM) and parallel factor analysis (PARAFAC). The percentages of mineralization of NOM in the UV/H2O2 and UV/PS processes were 20.5 and 83.3%, respectively, with a 10 mM oxidant dose and a contact time of 174 s (UV dose: approximately 30,000 mJ). Low-pressure, Hg UV lamp (254 nm) was applied in this experiment. The steady-state concentration of SO4[rad] was 38-fold higher than that of [rad]OH at an oxidant dose of 10 mM. With para-chlorobenzoic acid (pCBA) as a radical probe compound, we experimentally determined the rate constants of Suwannee River NOM (SRNOM) with [rad]OH (kOH/NOM = 3.3 × 108 M−1s−1) and SO4[rad] (kSO4-/NOM = 4.55 × 106 M−1s−1). The hydroxyl radical and sulfate radical showed different mineralization pathways of NOM, which have been verified by the use of LC-OCD and EEM/PARAFAC. Consequently, higher steady-state concentrations of SO4[rad], and different reaction preferences of [rad]OH and SO4[rad] with the NOM constituent had an effect on the mineralization efficiency.

Original languageEnglish
Pages (from-to)960-968
Number of pages9
JournalChemosphere
Volume184
DOIs
Publication statusPublished - 2017

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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