Defects on CoS_2−x: Tuning Redox Reactions for Sustainable Degradation of Organic Pollutants

Abstract

It is important to develop self‐producing reactive oxygen species (ROSs) systems and maintain the continuous and effective degradation of organic pollutants. Herein, for the first time, a system of ultrasound‐treated CoS2−x mixed with Fe2+ is constructed to sustainably release singlet oxygen (1O2) for the effective degradation of various organic pollutants, including dyes, phenols, and antibiotics. Ultrasonic treatment produces defects on the surface of CoS2 which promote the production of ROSs and the circulation of Fe3+/Fe2+. With the help of Co4+/Co3+ exposed on the surface of CoS2−x, the directional conversion of superoxide radical (.O2−) to 1O2 is realized. The CoS2−x/Fe2+ system can degrade organic pollutants efficiently for up to 30 days, which is significantly better than the currently recognized CuPx system (<3 days). Therefore, CoS2−x provides a new choice for the long‐term remediation of organic pollutants in controlling large area river pollution.

In Situ Hydroxylation of a Single-Atom Iron Catalyst for Preferential 1O2 Production from H2O2

“…To gain more accurate information of ROS generated in the Fe x CN/H 2 O 2 system, electron spin resonance measurements were performed. As shown in Figure a, triplet peak signals (1:1:1) derived from the addition of TEMPO with 1 O 2 were clearly obtained in all three systems, , while the signal intensity of TEMP– 1 O 2 in the presence of the Fe 0.1 CN catalyst was the strongest. The 1 O 2 production was generally recognized to originate from the recombination or direct oxidation of O 2 ·– . , Within expectations, when using methanol as the solvent, the detected signal intensities of DMPO–O 2 ·– was in the same order as Fe 0.1 CN > Fe 0.5 CN > C 3 N 4 > Fe 5.0 CN (Figure b), confirming the tight relation between 1 O 2 and O 2 ·– .…”

“…To gain more accurate information of ROS generated in the Fe x CN/H 2 O 2 system, electron spin resonance measurements were performed. As shown in Figure 5a, triplet peak signals (1:1:1) derived from the addition of TEMPO with 1 O 2 were clearly obtained in all three systems, 40,41 . When the trapping agent was replaced with DMPO, quadruple peak signals of DMPO−•OH (1:2:2:1) were observed.…”

Ultrahigh Adsorption Capacity and Kinetics of Vertically Oriented Mesoporous Coatings for Removal of Organic Pollutants

“…Organic pollutants in water resources, such as microcystins, benzene derivatives, dyes, and pesticides, have raised global concerns, which emerge as a big challenge to health of both humans and animals. [ 1–9 ] Various adsorbents including zeolites, peats, clays, and activated carbons have been used to remove them from water system. [ 9–17 ] Unfortunately, their microstructures including long diffusion pathway and small pore size (<2 nm) greatly limit their performances, including slow adsorption kinetics (of the order of hours), low adsorption capacity (<5% of adsorbent weight), and low surface utilization (<1% of total surface area).…”

Matrix effects on the performance and mechanism of Hg removal from groundwater by MoS2 nanosheets

“…Meanwhile the resulting ˙OH radicals caused nearly complete oxidation of MoS 2 to soluble Mo and S species. 66 In DI water, however, the reductive removal of Hg is slow because uncomplexed Hg( i ) is not stable and direct two-electron reduction is kinetically inhibited. 53 Thermodynamically, the formation of Hg 2 2+ associated with Cl is also favored over direct reduction to Hg 0 because the redox potential E ° for the Hg 2+ /Hg 2 2+ couple (0.91 V) is greater than that for the Hg 2+ /Hg 0 couple (0.85 V).…”