Advanced oxidation mechanism of UV photolysis of electrochemically generated free bromine

Kishimoto, Naoyuki; Hara, Koki

doi:10.1080/09593330.2020.1850876

Cited by 2 publications

(2 citation statements)

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“…The reactor used in this research was the same as that used in a previous study [14] and consisted of a photochemical reactor with an effective volume of 1.8 L and an undivided electrolytic flow cell with a plate cathode made of stainless steel (SUS 316, Japanese Industrial Standard) and a platedimensionally stable anode with a coating based on iridium oxide (JP-330, De Nora Permelec, Fujisawa, Japan) which is designed for chlorine evolution by dilute brine or seawater electrolysis. The effective electrode area was 21.0 cm 2 for each electrode, and the interelectrode gap was 0.11 cm.…”

Section: Equipmentmentioning

confidence: 99%

“…Accordingly, the radical scavenging effect of free bromine is expected to intensify under basic conditions. In addition to the reaction rates, HOBr is more easily photolyzed by UV light at 254 nm than BrO − [14]. As a result, the lifetime of BrO − in the photochemical reactor was longer than that of HOBr, which also increased the opportunity for scavenging radicals by BrO − .…”

Section: Von Gunten and Oliverasmentioning

confidence: 99%

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Availability of Seawater as A Chloride Source for UV/electro-chlorine Advanced Oxidation Process

Kishimoto

Hara

2021

J. of Wat. & Envir. Tech.

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This study reports the availability of seawater as an economical chloride (Cl − ) source for the UV/ electro-chlorine process from the viewpoints of advanced oxidation performance and unwanted byproduct formation of chlorate ion (ClO 3 − ) and bromate ion (BrO 3 − ). In the electrochemical oxidant production stage, the oxidant production rate in diluted seawater containing 30 mM Cl − was 21% lower than that in the NaCl solution due to coexisting electrolytes in the seawater. The ClO 3 − formation during electrolysis was successfully inhibited under acidic conditions and BrO 3 − formation was not detected in the diluted seawater. However, ClO 3 − and BrO 3 − were steadily formed in the undiluted seawater electrolysis, even when the initial pH value was set to 3. The oxidant utilization efficiency for 1,4-dioxane removal during UV irradiation was not deteriorated in the diluted seawater but decreased under basic conditions due to the radical scavenging effect of electrochemically produced free bromine and free chlorine. As a result, the formation of BrO 3 − and ClO 3 − was enhanced under basic conditions, whereas BrO 3 − formation was completely inhibited at an initial pH ≤ 5. Consequently, the diluted seawater was thought to be available as a Cl − source for the UV/electro-chlorine process if an acidic condition was maintained throughout the operation.

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Section: Equipmentmentioning

confidence: 99%

Section: Von Gunten and Oliverasmentioning

confidence: 99%