Natural soil as the peroxymonosulfate activator for efficient remediation and detoxification of bisphenol A: Nonradical-dominated mechanism and the change of soil properties

Abstract

Peroxymonosulfate (PMS) has been extensively applied in soil refractory organics remediation, but studies without an activator were scarce. Besides, the role of soil as well as the interaction between the soil constituents and PMS remained unclear. Using bisphenol A (BPA) as a model contaminant, our findings demonstrated that soil could efficiently activate PMS for BPA abatement in water and slurry. Free Fe oxides, especially crystalline Fe oxides in soil, were primarily responsible for PMS activation through nonradical pathways (singlet oxygen) for BPA removal, but soil organic matter (SOM) might inhibit the process. Moreover, BPA elimination was almost not inhibited by the addition of anions (Cl−, NO3−, HCO3−, and SO42−) and humic acid, but could be promoted by cations (Fe3+ and Mn2+). PMS oxidation caused an insignificant impact on the bioavailability of heavy metals, except for Fe, Mn, SOM, pH, total phosphorus (TP) content, soil composition, and crystal structure have not changed obviously after PMS treatment. BPA decomposition pathways were proposed based on the intermediates identified. Furthermore, the phytotoxicity of BPA − polluted soil was significantly reduced after PMS remediation in terms of crop growth indexes. Overall, the study provided new insights into the crucial role of soil constituents in PMS activation and inspired more energy or catalyst − saving soil remediation strategies.