Triplet state dissolved organic matter in aquatic photochemistry: reaction mechanisms, substrate scope, and photophysical properties

Environmental Science Processes & Impacts, Journal Year: 2016, Volume and Issue: 18(11), P. 1381 - 1399

Published: Jan. 1, 2016

Excited triplet states of chromophoric dissolved organic matter (³CDOM*) play a major role among the reactive intermediates produced upon absorption sunlight by surface waters.

Language: Английский

---

Unveiling the Origins of Selective Oxidation in Single-Atom Catalysis via Co–N₄–C Intensified Radical and Nonradical Pathways

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(16), P. 11635 - 11645

Published: July 11, 2022

Single-atom catalysts (SACs)-based peroxymonosulfate (PMS) systems are highly selective to the type of organic pollutants while mechanisms remain ambiguous. In this work, we carried out experimental and theoretical investigations reveal origins selectivity radical nonradical pathways in a designated Co–N4–C/PMS system. Two typical [bisphenol A (BPA) metronidazole (MNZ)] with different molecular structures were employed for comparison. We found that oxidation (SO4•– HO•) electron-transfer pathway (ETP) co-existed Pollutants (e.g., MNZ) high redox potential degraded primarily by free radicals rather than ETP, oxidization low-redox BPA) was dominated ETP at surface region Co–N4–C which overwhelmed contributions homogeneous phase. Intriguingly, could be manipulated PMS loading, simultaneously increased population elevated Co–N4–C-PMS* complexes ETP. Findings from work will unravel mysterious behavior SACs/PMS micropollutants.

Language: Английский

---

Merits and Limitations of Radical vs. Nonradical Pathways in Persulfate-Based Advanced Oxidation Processes

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(33), P. 12153 - 12179

Published: Aug. 3, 2023

Urbanization and industrialization have exerted significant adverse effects on water quality, resulting in a growing need for reliable eco-friendly treatment technologies. Persulfate (PS)-based advanced oxidation processes (AOPs) are emerging as viable technologies to treat challenging industrial wastewaters or remediate groundwater impacted by hazardous wastes. While the generated reactive species can degrade variety of priority organic contaminants through radical nonradical pathways, there is lack systematic in-depth comparison these pathways practical implementation different scenarios. Our comparative analysis reaction rate constants vs. indicates that radical-based AOPs may achieve high removal efficiency with relatively short contact time. Nonradical feature advantages minimal matrix interference complex wastewater treatments. (e.g., singlet oxygen, high-valent metals, surface activated PS) preferentially react bearing electron-donating groups, allowing enhancement degradation known target contaminants. For byproduct formation, analytical limitations computational chemistry applications also considered. Finally, we propose holistically estimated electrical energy per order (EE/O) parameter show significantly higher requirements pathways. Overall, critical comparisons help prioritize basic research PS-based inform merits system-specific applications.

Language: Английский

---

Cobalt Single Atoms Anchored on Oxygen‐Doped Tubular Carbon Nitride for Efficient Peroxymonosulfate Activation: Simultaneous Coordination Structure and Morphology Modulation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(29)

Published: May 6, 2022

Abstract Simultaneous regulation of the coordination environment single‐atom catalysts (SACs) and engineering architectures with efficient exposed active sites are strategies for boosting peroxymonosulfate (PMS) activation. We isolated cobalt atoms dual nitrogen oxygen (Co−N 3 O 1 ) on oxygen‐doped tubular carbon nitride (TCN) by pyrolyzing a hydrogen‐bonded cyanuric acid melamine–cobalt acetate precursor. The theoretically constructed Co−N moiety TCN exhibited an impressive mass activity 7.61×10 5 min −1 mol high 2 selectivity. Theoretical calculations revealed that single occupied environment, PMS adsorption was promoted energy barriers reduced key *O intermediate produced . were attached to widely used poly(vinylidene fluoride) microfiltration membrane deliver antibiotic wastewater treatment system 97.5 % ciprofloxacin rejection over 10 hours, thereby revealing suitability industrial applications.

Language: Английский

---

Ultrafast degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe3C/Fe@N-C-x: Singlet oxygen evolution and electron-transfer mechanisms

Applied Catalysis B Environment and Energy, Journal Year: 2022, Volume and Issue: 321, P. 122034 - 122034

Published: Oct. 10, 2022

Language: Английский

---

Heterogeneous activation of persulfate by metal and non-metal catalyst for the degradation of sulfamethoxazole: A review

Chemical Engineering Journal, Journal Year: 2022, Volume and Issue: 437, P. 135277 - 135277

Published: Feb. 16, 2022

Language: Английский

---

Rational Regulation of Co–N–C Coordination for High-Efficiency Generation of ¹O₂ toward Nearly 100% Selective Degradation of Organic Pollutants

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 8833 - 8843

Published: May 26, 2022

Single oxygen-based advanced oxidation processes (1O2-AOPs) exhibit great prospects in selective degradation of organic pollutants. However, efficient production 1O2 via tailored design catalysts to achieve contaminants remains challenging. Herein, we develop a simple strategy regulate the components and coordination Co–N–C at atomic level by adjusting Zn/Co ratio bimetallic zeolitic imidazolate frameworks (ZnxCo1-ZIFs). Zn4Co1–C demonstrates 98% removal phenol mixed phenol/benzoic acid (phenol/BA) solutions. Density functional theory calculations experiments reveal that more active CoN4 sites are generated Zn4Co1–C, which beneficial peroxymonosulfate activation generate 1O2. Furthermore, correlation between origin selectivity well-defined is systematically investigated electron paramagnetic resonance test quenching experiments. This work may provide novel insights into target pollutants complicated water matrix.

Language: Английский

---

Electron delocalization triggers nonradical Fenton-like catalysis over spinel oxides

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(31)

Published: July 25, 2022

Nonradical Fenton-like catalysis offers opportunities to overcome the low efficiency and secondary pollution limitations of existing advanced oxidation decontamination technologies, but realizing this on transition metal spinel oxide catalysts remains challenging due insufficient understanding their catalytic mechanisms. Here, we explore origins selectivity Fe-Mn identify electron delocalization surface active site as key driver its nonradical catalysis. Through fine-tuning crystal geometry trigger superexchange interaction at octahedra, ZnFeMnO4 with high-degree Mn-O unit was created enable near 100% activation peroxymonosulfate (PMS) unprecedented utilization efficiency. The resulting surface-bound PMS* complex can efficiently oxidize electron-rich pollutants extraordinary degradation activity, selectivity, good environmental robustness favor water applications. Our work provides a molecule-level bimetallic interactions oxides, which may guide design low-cost oxides for more selective efficient

Language: Английский

---

Ultrahigh Peroxymonosulfate Utilization Efficiency over CuO Nanosheets via Heterogeneous Cu(III) Formation and Preferential Electron Transfer during Degradation of Phenols

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 8984 - 8992

Published: May 31, 2022

In persulfate activation by copper-based catalysts, high-valent copper (Cu(III)) is an overlooked reactive intermediate that contributes to efficient utilization and organic pollutant removal. However, the mechanisms underlying heterogeneous enhanced are not fully understood. Here, oxide (CuO) nanosheets (synthesized with a facile precipitation method) exhibited high catalytic activity for peroxymonosulfate (PMS) 100% 4-chlorophenol (4-CP) degradation within 3 min. Evidence critical role of surface-associated Cu(III) on PMS 4-CP over wide pH range (pH 3-10) was obtained using in situ Raman spectroscopy, electron paramagnetic resonance, quenching tests. directly oxidized other phenolic pollutants, rate constants inversely proportional their ionization potentials. preferentially oxidizes rather than react two molecules generate one molecule 1O2, thus minimizing this less pathway. Accordingly, much higher efficiency (77% electrons accepted ascribed mineralization) CuO/PMS radical pathway-dominated Co3O4/PMS system (27%) or 1O2 α-MnO2/PMS (26%). Overall, these results highlight potential benefits via oxidation offer mechanistic insight into ultrahigh

Language: Английский

---

Oxygen doping of cobalt-single-atom coordination enhances peroxymonosulfate activation and high-valent cobalt–oxo species formation

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(16)

Published: April 11, 2023

The high-valent cobalt-oxo species (Co(IV)=O) is being increasingly investigated for water purification because of its high redox potential, long half-life, and antiinterference properties. However, generation Co(IV)=O inefficient unsustainable. Here, a cobalt-single-atom catalyst with N/O dual coordination was synthesized by O-doping engineering. O-doped (Co-OCN) greatly activated peroxymonosulfate (PMS) achieved pollutant degradation kinetic constant 73.12 min-1 g-2, which 4.9 times higher than that Co-CN (catalyst without O-doping) those most reported single-atom catalytic PMS systems. Co-OCN/PMS realized dominant oxidation pollutants increasing the steady-state concentration (1.03 × 10-10 M) 5.9 compared Co-CN/PMS. A competitive kinetics calculation showed contribution to micropollutant 97.5% during process. Density functional theory calculations influenced charge density (increased Bader transfer from 0.68 0.85 e), optimized electron distribution Co center d-band -1.14 -1.06 eV), enhanced adsorption energy -2.46 -3.03 eV, lowered barrier key reaction intermediate (*O*H2O) formation 1.12 0.98 eV. Co-OCN fabricated on carbon felt flow-through device, continuous efficient removal micropollutants (degradation efficiency >85% after 36 h operation). This study provides new protocol activation elimination through heteroatom-doping metal-oxo purification.

Language: Английский

---