Influence of anions on ozonation of bisphenol AF: Kinetics, reaction pathways, and toxicity assessment

In this article, the degradation of 4, 4'-(hexafluoroisopropylidene) diphenol (bisphenol AF, BPAF) by ozone was studied and toxicity of the degradation products was evaluated. Kinetic studies showed that acidic conditions were more conducive to the ozone degradation of BPAF than alkaline conditions. In the presence of common anions, Br- and SO42- promoted the degradation of BPAF, whereas NO2-, NO3-, HSO3- inhibited the degra-dation, and the other anions and cations had no significant effect. The degradation products were analyzed by mass spectrometry, and were mainly manifested in hydroxylation, carboxylation and cleavage of benzene ring. The addition of NO2-, HSO3- and Br- produced the corresponding free radicals, resulting in the parent com-pound being attacked and affecting the degradation efficiency and pathways. The theoretical calculated results showed that the ortho-site of the BPAF phenolic hydroxyl group was more active than the meta-position, and it's more likely for free radicals to attack ortho-sites and initiate substitution reactions. Toxicity assessment of the products in the process of ozone degradation showed that toxicity of the products was reduced by benzene ring cleavage and a reduction in the F atomic number. However, the toxicity of nitro and brominated products of BPAF was increased. These findings provide some new insights into the role of common ions in ozonation process and product formation, and supplement the existing conclusions. The results of this study remind future re-searchers to concern that inorganic ions in real water may be converted into corresponding free radicals that affect the formation of ozone oxidation products.

Automated summary

This study investigated the degradation of BPAF by ozone and the toxicity of its degradation products. The results showed that acidic conditions and specific ions play important roles in the ozone degradation of BPAF, and the toxicity of the products varied depending on the chemical structure. These findings provide new insights into the role of ions in the ozonation process and highlight the importance of considering the impact of inorganic ions in water on the formation of ozone oxidation products.