Simultaneous electrochemical detection of ozone and free chlorine with a boron-doped diamond electrode

Zhen Peng, None Irkham, Kazumi Akai, Michio Murata, Mai Tomisaki, Yasuaki Einaga

Research output: Contribution to journalArticlepeer-review

Abstract

O3 and free chlorine play significant roles in disinfection and organic degradation. There are numerous reports about their mixed-use, yet detection of the residual concentrations is not easily accomplished, whilst the interactions between them remain unclear. Herein, we develop a detection method using a boron-doped diamond (BDD) electrode to achieve the simultaneous determination of O3 and free chlorine, which benefits from the unique property of the wide potential window of BDD electrodes. It is indicated that O3 can always be accurately determined at 0.35 V vs. Ag/AgCl in an acidic solution (pH = 4-5), whether or not free chlorine is present in the solution, whereas free chlorine can be precisely monitored at −0.78 V vs. Ag/AgCl only after the O3 is completely depleted. Furthermore, in a basic solution (pH = 9-10), the reduction peak of O3 at 0.57 V vs. Ag/AgCl promptly disappears accompanied by a decrease in the peak current of free chlorine at 1.41 V. All the phenomena observed in the acidic and basic solutions are concurrently confirmed in a quasi-neutral solution. Based on these complementary measurements, a mechanism is proposed, in which the O3 reduction results in partial oxidation of the BDD surface, hindering the reduction of free chlorine in the acidic mixture; whereas O3 reacts quickly with free chlorine in the basic solution, which causes the co-consumption of both of them. It is hoped these results will give us a guide as to how better utilize mixtures and more precisely simultaneously determine O3 and free chlorine in the mixture.

Original languageEnglish
Pages (from-to)1655-1662
Number of pages8
JournalAnalyst
Volume147
Issue number8
DOIs
Publication statusPublished - Mar 14 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

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