Hydrated Electrons Trigger the Breakdown of Recalcitrant Cyanuric Acid in Wastewater

作者：Xin Luo, Wenxiao Zheng, Qiaoxin Li, Huanxin Ma, Rundong Chen, Xueming Liu, Chunhua Feng · 发表于：Environmental Science & Technology · 年份：2025 · DOI：10.1021/acs.est.4c11652 · 被引用次数：10 · 研究领域：Melamine detection and toxicity、Advanced oxidation water treatment、Water Treatment and Disinfection

Cyanuric acid (CA), a triazine-ring compound commonly used as a stabilizer for free chlorine to enhance disinfection, often persists in wastewater for the production of chlorinated cyanurates (Cl-CAs), posing challenges for treatment. This study demonstrates that conventional advanced oxidation processes (UV/H 2 O 2 and UV/peroxydisulfate) are ineffective in degrading CA, while the UV/sulfite system successfully achieves its breakdown. Hydrated electrons (e aq – ) were identified as the primary reactive species responsible for cleaving the stable triazine ring, with minimal contributions from SO 3 •– and H • . The pH value influences both the activity of e aq – and the degradability of CA by altering its structure; lower pH increases the electron-deficient regions in dihydrogen CA, enhancing its susceptibility to nucleophilic attack by e aq – . The high concentrations of Cl – can inhibit CA removal, likely due to the formation of reactive chlorine species that react with sulfite and suppress e aq – production. Effective CA degradation was also demonstrated in real wastewater, highlighting the UV/sulfite system as a sustainable solution for water treatment. These findings offer valuable insights into CA transformation and present effective approaches for eliminating emerging contaminants in the context of the extensive use of disinfectants.