Activation of hydrogen peroxide, persulfate, and free chlorine by steel anode for treatment of municipal and livestock wastewater: Unravelling the role of oxidants speciation

Thoughtful design of a covalent organic framework with tailor-made polarity and pore size for the enrichment of bisphenols and their derivatives: Extraction performance, adsorption mechanism and toxicity evaluation

A stable, reusable and cost-effective covalent organic framework (COF) with medium polarity was successfully decorated on Fe₃O₄. The Fe₃O₄@COF contained tailor-made polarity and pore size that fitted well with bisphenols and their derivatives (BPs). When coupling magnetic solid-phase extraction (MSPE) with high-performance liquid chromatography (HPLC) detection, the Fe₃O₄@COF featured efficient recognition and enrichment for BPs due to π-π stacking, C-H⋯π interactions, pore-filling effect, dispersion force and hydrophobic interactions. Under optimized conditions, calibration plots exhibited good linearity (5-1000 ng mL^-1), and limits of detection (LOD) ranged from 0.15 to 0.39 ng mL^-1. The method was successfully employed in quantifying BPs in authentic lake and river water samples with satisfactory recoveries ranging from 81.4% to 120%. Molecular dynamics simulation revealed extraction mechanisms, and a microscopic behavior related to the clustering property of the emerging brominated compounds was first discovered. Ecotoxicological assessments of target pollutants were conducted from multiple aspects, highlighting the harmfulness of the chemicals and the significance of the analytical method. The proposed methodology offered sensitive detection and quantification, which was beneficial for the timely tracking of the concentration, transportation and distribution of BPs to better explore their environmental behavior and tackle contamination problems in complex environmental matrices.

Activation of peroxymonosulfate by palygorskite-mediated cobalt-copper-ferrite nanoparticles for bisphenol S degradation: Influencing factors, pathways and toxicity evaluation

Peroxymonosulfate (PMS)-based advanced oxidation process is considered a potential technology for water treatment. Here, palygorskite (PAL)-mediated cobalt-copper-ferrite nanoparticles (16%-CoCu_0.4Fe_1·6O₄@PAL, donated as 16%-CCFO@PAL) were employed for PMS activation to remove bisphenol S (BPS). BPS degradation was greater than 99% under the optimal conditions within 25 min, on which the effects of various influencing factors were explored. The adsorption dissociation energy of PMS over 16%-CCFO@PAL was -6.27 eV, which was lower than that of the Cu-free catalyst (-6.15 eV), demonstrating the excellent catalytic ability of 16%-CCFO@PAL. The efficient catalytic ability of 16%-CCFO@PAL was also verified in real water samples. The oxidation intermediates were identified and their generations were systematically analyzed by DFT calculations. The possible degradation pathways of BPS were proposed and the toxicity of products was predicted. BPS affected the normal development of zebrafish embryos and the levels of sex hormone in adult male zebrafish, and was harmful to the tissues, such as testis, liver, and intestine of zebrafish. The 16%-CCFO@PAL/PMS process can effectively reduce the toxicity of BPS-polluted water. This study paves the way for the real application of 16%-CCFO@PAL/PMS oxidation process and provides a new perspective for the evaluation of water toxicity.