Citation: Wenxiao Zheng, Jianyu Pan, Xin Luo, Huanxin Ma, Rundong Chen, Chunhua Feng. Tandem photochemical reduction-electrochemical oxidation process for extensive mineralization of refractory cyanuric acid in wastewater[J]. Chinese Chemical Letters, ;2026, 37(9): 112434. doi: 10.1016/j.cclet.2026.112434 shu

Tandem photochemical reduction-electrochemical oxidation process for extensive mineralization of refractory cyanuric acid in wastewater

The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China

chfeng@scut.edu.cn

Received Date: 4 August 2025
Revised Date: 22 November 2025
Accepted Date: 18 January 2026
Available Online: 20 January 2026

Figures(5)

Cyanuric acid (CA), a stable triazine-based compound widely used in chlorinated disinfectants, has emerged as a recalcitrant contaminant frequently detected in aquatic environments. Due to its high chemical stability and electron-deficient structure, CA resists degradation by conventional oxidative processes. Here, a tandem UV/sulfite (SF)-based photochemical reduction-electrochemical oxidation (EO) process was developed to achieve complete mineralization of CA. Hydrated electrons generated in the UV/SF process efficiently induce triazine ring-opening, while EO further oxidizes the resulting intermediates. Density functional theory calculations and quenching experiments revealed that CA exhibits high activation barriers toward direct oxidation by ^•OH and SO₄^•−, explaining their limited reactivity. In contrast, direct electron transfer to the boron-doped diamond (BDD) anode dominates CA degradation in the EO process, albeit with sluggish kinetics due to the high oxidation potential. The tandem system effectively lowers the oxidative energy barrier via reductive fragmentation. Moreover, the UV/SF-EO process demonstrated reliable and effective performance in natural waters and industrial effluents. This study not only highlights the synergistic benefits of coupling reduction and oxidation for the treatment of persistent organic pollutants but also provides mechanistic insight into CA degradation pathways, offering a promising strategy for mitigating CA pollution in complex water environments.
- UV/sulfite,
- Electrochemical oxidation,
- Tandem process,
- Cyanuric acid,
- Complete mineralization,
- Reaction mechanism
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