Kaiting Zhang, Yuwei Xie, Zhantu Ye, Weifeng Zhang, Qian Zhang, Xin Yu, Mingbao Feng*

Chemical Engineering Journal

https://doi.org/10.1016/j.cej.2023.141879

Published: 1 April 2023

Abstract

Periodate (PI)-based oxidation processes are garnering worldwide increasing attention in the oxidative water treatment field. Unfortunately, the influence of water constituents on the transformation-driven product formation and risks of organic micropollutants remains largely unknown. This study firstly reports that naturally occurring iodide (I−) greatly enhances the PI oxidation of multiple phenolic compounds (e.g., bisphenol A) under different application scenarios (e.g., solution pH and high salinity). Furthermore, an improved bacterial inactivation with 3-log reduction is found after 30 min of PI treatment in the presence of I−. Comparatively, such enhancement is not observed during PI/I− treatment of six non-phenolic contaminants such as sulfadiazine, atrazine, and carbamazepine. Multi-evidence explorations demonstrate hypoiodous acid (HOI) as the dominant oxidizing species for accelerated phenolic oxidation. Based on the high-resolution mass spectroscopic analysis, PI/I−-mediated transformation of bisphenols and 4-chlorophenol yields different iodinated aromatic products with enhanced persistence, bioaccumulation, and toxicity. Taken together, this investigation unveils that I− could selectively alter phenolics’ transformation behaviors and fate when using PI-based oxidation strategies in water. Particular concern should be concentrated on the treatment-driven secondary risks of iodinated aromatic products, which also behave as the precursors of highly toxic iodinated disinfection byproducts during water disinfection.