Reports that promote persulfate-based advanced oxidation process (AOP) as a viable alternative to hydrogen peroxide-based processes have been rapidly accumulating in recent water treatment literature. Various strategies to activate peroxide bonds in persulfate precursors have been proposed and the capacity to degrade a wide range of organic pollutants has been demonstrated. Compared to traditional AOPs in which hydroxyl radical serves as the main oxidant, persulfate-based AOPs have been claimed to involve different in situ generated oxidants such as sulfate radical and singlet oxygen as well as nonradical oxidation pathways. However, there exist controversial observations and interpretations around some of these claims, challenging robust scientific progress of this technology toward practical use. This Critical Review comparatively examines the activation mechanisms of peroxymonosulfate and peroxydisulfate and the formation pathways of oxidizing species. Properties of the main oxidizing species are scrutinized and the role of singlet oxygen is debated. In addition, the impacts of water parameters and constituents such as pH, background organic matter, halide, phosphate, and carbonate on persulfate-driven chemistry are discussed. The opportunity for niche applications is also presented, emphasizing the need for parallel efforts to remove currently prevalent knowledge roadblocks.

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Persulfate-Based Advanced Oxidation: Critical Assessment of Opportunities and Roadblocks.

The use of zero-valent iron for groundwater remediation and wastewater treatment: a review.

Review on nano zerovalent iron (nZVI): From synthesis to environmental applications

Reactive species in advanced oxidation processes: Formation, identification and reaction mechanism

Iron-mediated activation of persulfate and peroxymonosulfate in both homogeneous and heterogeneous ways: A review

Catalytic degradation of sulfamethoxazole through peroxymonosulfate activated with expanded graphite loaded CoFe2O4 particles

In this study, in order to further investigate the degradation capacity and mechanism of Fe/Cu bimetallic system, the prepared Fe/Cu bimetallic particles with different theoretical copper mass loadings (0.05, 0.11, 0.24, 0.41, 0.62, 0.89, 1.26 and 1.81 g Cu/g Fe) were characterized by SEM, EDS, XRD and laser particle size analyzer. Also, the effect of theoretical Cu mass loading and five key operating parameters on the PNP removal efficiency was investigated thoroughly. Furthermore, the mineralization process of PNP was studied by using COD, TOC, UV–vis spectra, FTIR spectra and GC/MS. The results show that a large number of fine Cu particles were produced from the excessive theoretical Cu mass loading, and they facilitated the catalytic reactivity of the Fe/Cu bimetallic particles at Cu loading

Removal of p-nitrophenol (PNP) in aqueous solution by the micron-scale iron–copper (Fe/Cu) bimetallic particles

Efficient degradation of sulfamethoxazole by the CuO@Al2O3 (EPC) coupled PMS system: optimization, degradation pathways and toxicity evaluation.

A new potential oxidation process is provided by CuFe2O4/hydroxylamine (HA) system for degradation of antibiotics in water. The CuFe2O4/HA system can generate reactive oxygen species (ROS) for the degradation of sulfamethoxazole (SMX). The addition of radical scavengers, including benzoquinone (BQ) and catalase (CAT), inhibited the oxidation of SMX in CuFe2O4/HA system. Electron transfer in the CuFe2O4/HA system played a key function for the generation of ROS and the degradation of SMX. The main ROS, was the superoxide radical (O2•-) mainly generated from adsorbed oxygen (O2(A)), which came from the oxidation of the lattice oxygen (O2-(L)) in CuFe2O4. The CuFe2O4/HA system was effectively applicable for a broad pH range (approximately 5-10). In addition, the activation mechanism for CuFe2O4/HA system was studied with the target contaminant SMX. Finally, the degradation pathways of SMX were proposed under the optimal conditions in CuFe2O4/HA system.

Activation CuFe2O4 by Hydroxylamine for Oxidation of Antibiotic Sulfamethoxazole.

Improving the degradation of atrazine in the three-dimensional (3D) electrochemical process using CuFe2O4 as both particle electrode and catalyst for persulfate activation

Yunhong Zhang

Papers

Catalytic degradation of sulfamethoxazole through peroxymonosulfate activated with expanded graphite loaded CoFe2O4 particles

Removal of p-nitrophenol (PNP) in aqueous solution by the micron-scale iron–copper (Fe/Cu) bimetallic particles

Efficient degradation of sulfamethoxazole by the CuO@Al2O3 (EPC) coupled PMS system: optimization, degradation pathways and toxicity evaluation.

Activation CuFe2O4 by Hydroxylamine for Oxidation of Antibiotic Sulfamethoxazole.

Improving the degradation of atrazine in the three-dimensional (3D) electrochemical process using CuFe2O4 as both particle electrode and catalyst for persulfate activation