TY - JOUR
T1 - Simultaneous electrochemical detection of ozone and free chlorine with a boron-doped diamond electrode
AU - Peng, Zhen
AU - Irkham, None
AU - Akai, Kazumi
AU - Murata, Michio
AU - Tomisaki, Mai
AU - Einaga, Yasuaki
N1 - Funding Information:
This work was partially supported by JSPS Grant-in-Aid for Scientific Research A 19H00832 (to Y. E.), China Scholarship Council and Japan Science and Technology Agency (to Z. P.).
Publisher Copyright:
© 2022 The Royal Society of Chemistry
PY - 2022/3/14
Y1 - 2022/3/14
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85128142280&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85128142280&partnerID=8YFLogxK
U2 - 10.1039/d1an02347k
DO - 10.1039/d1an02347k
M3 - Article
C2 - 35311863
AN - SCOPUS:85128142280
SN - 0003-2654
VL - 147
SP - 1655
EP - 1662
JO - The Analyst
JF - The Analyst
IS - 8
ER -