Monuron photodegradation using peroxymonosulfate activated by non-metal-doped TiO2 under visible LED and the modeling via a parallel-serial kinetic approach

Amal Abdelhaleem, Wei Chu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

21 Citations (Scopus)

Abstract

N-doped TiO2 (NT) was proven to be efficient for monuron decay via peroxymonosulfate (PMS) activation under visible LED (Vis LED). The activation mechanism revealed that [rad]OH and SO4[rad] have a critical role in the monuron decay with a ratio of about 3 to 1, respectively; and the holes at the catalyst surface are the main precursors in forming SO4[rad]. The NT/PMS/Vis LED hybrid process was found to be an effective approach under a wide solution pH range of 2.5–9.2 (>80% decay). Interestingly, the highest efficiency was observed at pH 9.2 due to the contribution of PMS/Vis LED process by generating both [rad]OH and SO4[rad] at alkaline pH. However, the decay rate of monuron was inhibited at pH 11.6 due to the dissociation of [rad]OH into O[rad] and the electrostatic repulsion among reagents. The process was also suitable for ion-rich wastewater since no significant reduction in the performance was induced in the presence of high concentrations of inorganic anions. Furthermore, the process was proven to be a promising approach for mineralization of monuron and its intermediates. Twenty reaction intermediates were detected and five of them are newly reported. A novel mathematical model was established based on reaction intermediates using a parallel-serial-irreversible reaction approach, which is helpful in predicting the detoxification extent of hazardous intermediates.

Original languageEnglish
Pages (from-to)411-421
Number of pages11
JournalChemical Engineering Journal
Volume338
DOIs
Publication statusPublished - 15 Apr 2018

Keywords

  • Herbicides
  • Mathematical model
  • Photodegradation
  • PMS activation
  • Visible LED

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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