Origins of Electron-Transfer Regime in Persulfate-Based Nonradical Oxidation Processes

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 56(1), P. 78 - 97

Published: Dec. 21, 2021

Persulfate-based nonradical oxidation processes (PS-NOPs) are appealing in wastewater purification due to their high efficiency and selectivity for removing trace organic contaminants complicated water matrices. In this review, we showcased the recent progresses of state-of-the-art strategies electron-transfer regimes PS-NOPs, including design metal metal-free heterogeneous catalysts, situ/operando characterization/analytical techniques, insights into origins mechanisms. a typical process (ETP), persulfate is activated by catalyst form surface complexes, which directly or indirectly interact with target pollutants finalize oxidation. We discussed different analytical techniques on fundamentals tactics accurate analysis ETP. Moreover, demonstrated challenges proposed future research ETP-based systems, such as computation-enabled molecular-level investigations, rational real-scenario applications environment. Overall, review dedicates sharpening understanding ETP PS-NOPs presenting promising remediation technology green chemistry.

Language: Английский

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Assessment of the validity of the quenching method for evaluating the role of reactive species in pollutant abatement during the persulfate-based process

Water Research, Journal Year: 2022, Volume and Issue: 221, P. 118730 - 118730

Published: June 10, 2022

Language: Английский

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Enhanced Oxidation of Organic Contaminants by Iron(II)-Activated Periodate: The Significance of High-Valent Iron–Oxo Species

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(11), P. 7634 - 7642

Published: March 12, 2021

Potassium periodate (PI, KIO4) was readily activated by Fe(II) under acidic conditions, resulting in the enhanced abatement of organic contaminants 2 min, with decay ratios selected pollutants even outnumbered those Fe(II)/peroxymonosulfate and Fe(II)/peroxydisulfate processes identical conditions. Both 18O isotope labeling techniques using methyl phenyl sulfoxide (PMSO) as substrate X-ray absorption near-edge structure spectroscopy provided conclusive evidences for generation high-valent iron-oxo species (Fe(IV)) Fe(II)/PI process. Density functional theory calculations determined that reaction PI followed formation a hydrogen bonding complex between Fe(H2O)62+ IO4(H2O)-, ligand exchange, oxygen atom transfer, consequently generating Fe(IV) species. More interestingly, unexpected detection 18O-labeled hydroxylated PMSO not only favored simultaneous ·OH but also demonstrated indirectly produced through self-decay to form H2O2 subsequent Fenton reaction. In addition, IO4- transformed into undesired iodine (i.e., HOI, I2, I3-) converted nontoxic iodate (IO3-). This study proposed an efficient environmental friendly process rapid removal emerging enriched understandings on evolution mechanism Fe(IV)-mediated processes.

Language: Английский

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Assessing the Use of Probes and Quenchers for Understanding the Reactive Species in Advanced Oxidation Processes

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(13), P. 5433 - 5444

Published: March 17, 2023

Advanced oxidation processes (AOPs) are increasingly applied in water and wastewater treatment. Understanding the role of reactive species using probes quenchers is one main requirements for good process design. However, much fundamental kinetic data reactions with lacking, probably leading to inappropriate probe quencher selection dosing. In this work, second-order rate constants over 150 such as •OH, SO4•-, Cl• chemical oxidants free chlorine persulfate were determined. Some previously ill-quantified (e.g., furfuryl alcohol methyl phenyl sulfoxide certain oxidants, nitrobenzene 1,4-dioxane halogen radicals) found be kinetically favorable. The specific can guided by improved database. criteria properly choosing dosages proposed along a procedure quantifying interference from addition. limitations approaches explicated, possible solutions combination other tools) proposed. Overall, database protocols provided work benefit future research understanding radical chemistry AOPs well radical-involved processes.

Language: Английский

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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

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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

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Water decontamination via nonradical process by nanoconfined Fenton-like catalysts

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: May 19, 2023

Abstract There is an urgent need to develop effective and sustainable solutions reduce water pollution. Heterogeneous Fenton-like catalysts are frequently used eliminate contaminants from water. However, the applicability of these limited due low availability reactive species (RS). Herein, nanoconfinement strategy was applied encapsulate short-lived RS at nanoscale boost utilization efficiency in reactions. The nanoconfined catalyst fabricated by assembling Co 3 O 4 nanoparticles carbon nanotube nanochannels achieve exceptional reaction rate excellent selectivity. Experiments collectively suggested that degradation attributed singlet oxygen ( 1 2 ). Density functional theory calculations demonstrated space contributes quantum mutation alters transition state lower activation energy barriers. Simulation results revealed enrichment contaminant on reduced migration distance enhanced . synergy between shell layer core-shell structure further improved selectivity towards oxidation real waters. expected provide a viable for pollution control.

Language: Английский

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Persulfate Oxidation of Sulfamethoxazole by Magnetic Iron-Char Composites via Nonradical Pathways: Fe(IV) Versus Surface-Mediated Electron Transfer

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(14), P. 10077 - 10086

Published: July 2, 2021

Despite the vital roles of reactive radical species in coupled iron–carbon composite/persulfate (PS) system for eliminating pollutants, nonradical contributions are typically overlooked. Herein, we developed two efficient magnetic iron–char composites via low-temperature (BCFe-400) and high-temperature (BCFe-700) pyrolysis. The activated PS through pathways sulfamethoxazole (SMX) degradation. In BCFe-400/PS system, high-valent iron Fe(IV) was dominant active oxidation, evidenced by methyl phenyl sulfoxide-based probe tests, Mössbauer spectroscopy, situ Raman analyses with kinetic evaluation. BCFe-700/PS surface-mediated electron transfer dominated regime probed electrochemical test analysis. Furthermore, maintained high efficiency continuous degradation SMX due to feasible Fe2+generation toward formation. stability limited hindered between surface complex (i.e., BCFe-700–PS*) SMX, thermal treatment would help recover reactivity. Both systems exhibited performances removal presence chloride humic acid real water matrixes (e.g., seawater, piggery wastewater, landfill leachate), exhibiting great merits system. Overall, study provide new insights into activation iron-loaded catalysts efficiently degrade pollutants pathways.

Language: Английский

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Interface Engineering of Co(OH)₂ Nanosheets Growing on the KNbO₃ Perovskite Based on Electronic Structure Modulation for Enhanced Peroxymonosulfate Activation

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(8), P. 5200 - 5212

Published: April 8, 2022

Material-enhanced heterogonous peroxymonosulfate (PMS) activation on emerging organic pollutant degradation has attracted intensive attention, and a challenge is the electron transfer efficiency from material to PMS for radical production. Herein, an interface architecture of Co(OH)2 nanosheets growing KNbO3 perovskite [Co(OH)2/KNbO3] was developed, which showed high catalytic activity in activation. A reaction rate constant (k1) 0.631 min-1 complete removal pazufloxacin within 5 min were achieved. X-ray photoelectron spectroscopy, absorption near edge structure spectra, density functional theory (DFT) calculations revealed successful construction modulated electronic Co(OH)2/KNbO3, resulting hole accumulation KNbO3. Bader topological analysis charge distribution further indicates that occupations Co-3d O-2p orbitals Co(OH)2/KNbO3 are pushed above Fermi level form antibonding states (σ*), leading chemisorption affinity PMS. In addition, more reactive Co(II) with closer d-band center results higher lower decomposition energy SO4•-. Moreover, sites SO4•- attack precisely identified based DFT calculation Fukui index. The pathways proceeded as decarboxylation, nitroheterocyclic ring opening reaction, defluorination, hydroxylation. This work can provide potential route developing advanced catalysts manipulation enhanced Fenton-like such

Language: Английский

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Toward Selective Oxidation of Contaminants in Aqueous Systems

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(21), P. 14494 - 14514

Published: Oct. 20, 2021

The presence of diverse pollutants in water has been threating human health and aquatic ecosystems on a global scale. For more than century, chemical oxidation using strongly oxidizing species was one the most effective technologies to destruct ensure safe clean supply. However, removal increasing amount with higher structural complexity, especially emerging micropollutants trace concentrations complicated matrix, requires excessive dosage oxidant and/or energy input, resulting low cost-effectiveness possible secondary pollution. Consequently, it is practical significance but scientifically challenging achieve selective interest for decontamination. Currently, there are variety examples concerning aqueous systems. systematic understanding relationship between origin selectivity its applicable treatment scenarios, as well rational design catalyst catalytic oxidation, still lacking. In this critical review, we summarize state-of-the-art strategies decontamination probe origins selectivity, that is, from reactivity either oxidants or target pollutants, arising accessibility via adsorption size exclusion, due interfacial electron transfer process enzymatic oxidation. Finally, challenges perspectives briefly outlined stimulate future discussion decontamination, particularly toward application real scenarios.

Language: Английский

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