Complexation with Metal Ions Affects Chlorination Reactivity of Dissolved Organic Matter: Structural Reactomics of Emerging Disinfection Byproducts

作者：Qian Hu, Mingxuan Lou, Ruigang Wang, Sai Bai, He Guo, Jianbin Zhou, Qiuling Ma, Tiecheng Wang, Lingyan Zhu, Xiangru Zhang · 发表于：Environmental Science & Technology · 年份：2024 · DOI：10.1021/acs.est.4c03022 · 被引用次数：35 · 研究领域：Water Treatment and Disinfection、Environmental remediation with nanomaterials、Mercury impact and mitigation studies

Metal ions are liable to form metal–dissolved organic matter [dissolved organic matter (DOM)] complexes, changing the chemistry and chlorine reactivity of DOM. Herein, the impacts of iron and zinc ions (Fe 3+ and Zn 2+ ) on the formation of unknown chlorinated disinfection byproducts (Cl-DBPs) were investigated in a chlorination system. Fe 3+ preferentially complexed with hydroxyl and carboxyl functional groups, while Zn 2+ favored the amine functional groups in DOM. As a consequence, electron-rich reaction centers were created by the C–O–metal bonding bridge, which facilitated the electrophilic attack of α-C in metal–DOM complexes. Size-reactivity continuum networks were constructed in the chlorination system, revealing that highly aromatic small molecules were generated during the oxidation and decarbonization of metal–DOM complexes. Molecular transformation related to C-R (R represents complex sites) loss was promoted via metal complexation, including decarboxylation and deamination. Consequently, complexation with Fe 3+ and Zn 2+ promoted hydroxylation by the C–O–metal bonding bridge, thereby increasing the abundances of unknown polychlorinated Cl-DBPs by 9.6 and 14.2%, respectively. The study provides new insights into the regulation of DOM chemistry and chlorine reactivity by metal ions in chlorination systems, emphasizing that metals increase the potential health risks of drinking water and more scientific control standards for metals are needed.