Bromate abatement with ultraviolet light-emitting diode/thiosulfate advanced reduction processes: Mechanisms, affecting parameters and applications
Issued Date
2026-03-01
Resource Type
ISSN
03014797
eISSN
10958630
Scopus ID
2-s2.0-105029224639
Journal Title
Journal of Environmental Management
Volume
401
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SCOPUS
Bibliographic Citation
Journal of Environmental Management Vol.401 (2026)
Suggested Citation
Phan K.A., Pornsuwan S., Oguma K., Lohwacharin J. Bromate abatement with ultraviolet light-emitting diode/thiosulfate advanced reduction processes: Mechanisms, affecting parameters and applications. Journal of Environmental Management Vol.401 (2026). doi:10.1016/j.jenvman.2026.128835 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/114947
Title
Bromate abatement with ultraviolet light-emitting diode/thiosulfate advanced reduction processes: Mechanisms, affecting parameters and applications
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Abstract
Bromate, a possible carcinogenic byproduct of ozonation, is potentially removed by the ultraviolet (UV)/sulfite advanced reduction process (ARP), with hydrated electrons playing a major role. However, this process becomes less efficient under acidic to neutral pHs and remains limited to the use of conventional mercury UV lamps. To address these issues, a UV-light emitting diode (UV-LED)-based ARP was studied for bromate removal using thiosulfate as an alternative reducing agent and UV-LEDs emitting at 265 nm and 280 nm as a radiation source. The UV-LED<inf>265</inf>/thiosulfate process effectively reduced 100 ± 0.0% of the initial bromate concentration (4.0 μM) at pH 6.4 ± 0.1, following the pseudo first-order rate constant of 1.3 × 10<sup>−2</sup> min<sup>−1</sup>. Meanwhile, the UV-LED<inf>265</inf>/sulfite process attained only 11.6 ± 1.4% bromate degradation efficiency. Results of electron paramagnetic resonance and scavenging experiments indicate that hydrated electrons and sulfite radicals derived from the UV-LED<inf>265</inf>/thiosulfate process played a significant role in bromate degradation. The process demonstrated optimal performance within a pH range of 5.8–6.4, with higher thiosulfate doses accelerating the bromate removal efficiency. Furthermore, excessive chloride and bicarbonate concentrations interfered with the bromate removal. Comparable energy consumption (electrical energy per order of 27.4 kWh/m<sup>3</sup>) with UV/sulfite processes has demonstrated the potential of UV-LED<inf>265</inf>/thiosulfate ARPs for effective bromate degradation, using a sustainable UV radiation source and compatible with acidic ozone-treated water.