On the mechanism and selectivity of a novel iodine/peracetic acid process for the efficient and rapid elimination of micropollutants
Rusen Zou, Wenqiang Yang, Babak Rezaei, Elise Broe Bendtsen, Kuangxin Guo, Kai Tang, Henrik Rasmus Andersen, Stephan Sylvest Keller, Yifeng Zhang
Abstract
In recent years, halogen radical-based advanced oxidation processes (AOPs) have shown promise for metal-free, highly selective elimination of phenolic pollutants with high mineralization. This study explored a novel approach combing peracetic acid (PAA) and naturally available I− to efficiently remove bisphenol A (BPA) over a broad pH range (2–8). A dose of 500 μM PAA and 100 μM I− at a pH of 3 completely eliminated 43.8 µM of BPA within 10 min. Aside from I−, two more halogen ions, Cl− and Br−, could also enhance BPA elimination in the presence of PAA. Based on quenching experiments and density functional theory (DFT) thermodynamic calculations, only I− among the three halogen ions can react with PAA (primarily through the single electron transfer pathway) to generate •I, which efficiently removes BPA. The Cl− and Br− only contribute partially to the BPA removal, mainly through HOCl and HOBr following the oxygen atom transfer pathway. The water matrices had no noticeable influence on the I−/PAA process, and eliminating micropollutants with electron-rich groups from actual water samples remained effective. This work proposes an innovative and feasible technique for PAA-based AOPs and showcases its promising applicability for the treatment of phenolic contaminants in wastewater.