Novel Visible Light-Driven Photocatalytic Chlorine Activation Process for Carbamazepine Degradation in Drinking Water

Zihang Cheng, Li Ling, Zihao Wu, Jingyun Fang, Paul Westerhoff, Chii Shang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Photolysis of free chlorine (HOCl/ClO-) is an advanced oxidation process (AOP) to produce hydroxyl (HO•) and other radicals for refractory micropollutant degradation. However, HOCl/ClO- is only conducive to activation and production of radicals by ultraviolet (UV) light. For the first time, we show the use of visible light (>400 nm) to produce HO• and ClO•, through use of graphitic carbon nitride (g-C3N4) and photogenerated hvb+, ecb-, and O2•- in the presence of HOCl/ClO-, which was termed visible light g-C3N4-enabled chlorine AOP (VgC-AOP). The VgC-AOP increased the pseudo first-order degradation rate constant of a model micropollutant, carbamazepine, by 16 and 7 times higher than that without g-C3N4 and HOCl/ClO-, respectively, and remained active over multiple use cycles. Effects of water quality [pH, alkalinity, Cu(II), and natural organic matter (NOM)] and the operational conditions (g-C3N4 and HOCl/ClO- concentrations, irradiation wavelength, and dose) were investigated. Of particular significance is its superior performance in the presence of NOM, which absorbs less light at visible light wavelengths and scavenges less surface-bonded reactive species, compared against UV/TiO2 or UV/chlorine AOPs. The VgC-AOP is practically relevant, feasible, and easily implementable and it expands the potential types of light sources (e.g., LEDs and solar light).

Original languageEnglish (US)
Pages (from-to)11584-11593
Number of pages10
JournalEnvironmental Science and Technology
Volume54
Issue number18
DOIs
StatePublished - Sep 15 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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