Persulfate enhanced photoelectrochemical oxidation of organic pollutants using self-doped TiO2nanotube arrays: Effect of operating parameters and water matrix

Aseom Son, Jiho Lee, Changha Lee, Kangwoo Cho, Jaesang Lee, Seok Won Hong

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigated the influence of adding peroxydisulfate (PDS) to a photoelectrocatalysis (PEC) system using self-doped TiO2 nanotube arrays (bl-TNAs) for organic pollutant degradation. The addition of 1.0 mM PDS increased the bisphenol-A (BPA) removal efficiency of PEC (PEC/PDS) from 65.0% to 85.9% within 1 h. The enhancement could be attributed to the high formation yield of hydroxyl radicals (·OH), increased charge separation, and assistance of the sulfate radicals (SO4·−). The PDS concentration and applied potential bias were influential operating parameters for the PEC/PDS system. In addition, the system exhibited a highly stable performance over a wide range of pH values and background inorganic and organic constituents, such as chloride ions, bicarbonate, and humic acid. Further, the degradation performance of the organic pollutant mixture, including BPA, 4-chlorophenol (4-CP), sulfamethoxazole (SMX), and carbamazepine (CBZ), was evaluated in 0.1 M (NH4)2SO4 solution and real surface water. The degradation efficiency increased in the order of CBZ < SMX < 4-CP < BPA in the PEC and PEC/PDS systems with both water matrices. Compared with the PEC system, the PEC/PDS (1.0 mM) system showed a threefold higher pseudo first-order reaction rate constant for BPA among pollutant mixtures in surface water. This was attributed to enhanced ·OH production and the selective nature of SO4·−. The pseudo first-order reaction rate constants of other pollutants, i.e., 4-CP, SMX, and CBZ increased ca. twofold in the PEC/PDS system. The results of this study showed that the PEC/PDS system with bl-TNAs is a viable technology for oxidative treatment.

Original languageEnglish
Article number116803
JournalWater Research
Volume191
DOIs
Publication statusPublished - 2021 Mar 1

Keywords

  • Organic pollutant
  • Peroxydisulfate
  • Photoelectrochemical
  • Reactive oxidant species
  • Self-doped TiOnanotube array

ASJC Scopus subject areas

  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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