Chlorinated cyanurates in drinking water: Measurement bias, stability, and disinfectant byproduct formation

Wahman, David G.; Alexander, Matthew T.; Dugan, Alison G.

doi:10.1002/aws2.1133

Cited by 1 publication

(1 citation statement)

References 30 publications

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“…The formation of undesired byproducts remains a concern of AOPs, especially when the processes involve chlorine-based disinfectants. NaCl 2 Cy and Cl 3 Cy have been found to generate lower concentrations of trihalomethanes (THMs) and haloacetic acids (HAAs) than free chlorine at the same initial total chlorine concentration of 4 mg L –1 as Cl 2 in surface water at pH 7.5. , However, whether the radicals generated in the UV 222 /Cl-cyanurates AOP increase the concentrations of byproducts remains unknown. Although cyanuric acid and Cl-cyanurates are inert to radicals (HO • , Cl • , and ClO • ), , whether UV 222 irradiation can destruct cyanuric acid and Cl-cyanurates to generate undesired byproducts remains to be explored.…”

Section: Introductionmentioning

confidence: 99%

A High-Radical-Yield Advanced Oxidation Process Coupling Far-UVC Radiation with Chlorinated Cyanurates for Micropollutant Degradation in Water

Zhao

Shang

Yin

2023

Environ. Sci. Technol.

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Increasing the radical yield and reducing energy consumption would enhance the sustainability and competitiveness of advanced oxidation processes (AOPs) for micropollutant degradation in water. We herein report a novel AOP coupling far-UVC radiation at 222 nm with chlorinated cyanurates (termed the UV222/Cl-cyanurates AOP) for radical generation and micropollutant abatement in water. We experimentally determined the concentrations of HO•, Cl•, and ClO• in the UV222/Cl-cyanurates AOP in deionized water and swimming pool water. The radical concentrations are 10–27 times and 4–13 times, respectively, higher than those in the UV254/Cl-cyanurates AOP and the well-documented UV254/chlorine AOP under comparable conditions (e.g., same UV fluence and oxidant dosing). We determined the molar absorption coefficients and innate quantum yields of two chlorine species and two Cl-cyanurates at 222 nm and incorporated these parameters into a kinetic model. The model enables accurate prediction of oxidant photodecay rates as well as the pH impact on radical generation in the UV222/Cl-cyanurates AOP. We predicted the pseudo-first-order degradation rate constants of 25 micropollutants in the UV222/Cl-cyanurates AOP and demonstrated that many micropollutants can be degraded by >80% with a low UV fluence of 25 mJ cm–2. This work advances the fundamental photochemistry of chlorine and Cl-cyanurates at 222 nm and offers a highly effective engineering tool in combating micropollutants in water where Cl-cyanurates are suitable to use.

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