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Twistedly hydrophobic basis with suitable aromatic metrics in covalent organic networks govern micropollutant decontamination-亚洲成人在线一二三四五六区

1706186130 — Tue, 23 Jan 2024 09:29:41 +0000

Qin C, Yang Y, Wu X, Chen L, Liu Z, Tang L, Lyu L, Huang D, Wang D, Zhang C, et al. Twistedly hydrophobic basis with suitable aromatic metrics in covalent organic networks govern micropollutant decontamination. NATURE COMMUNICATIONS. 2023;14.Abstract

The pre-designable structure and unique architectures of covalent organic frameworks (COFs) render them attractive as active and porous medium for water crisis. However, the effect of functional basis with different metrics on the regulation of interfacial behavior in advanced oxidation decontamination remains a significant challenge. In this study, we pre-design and fabricate different molecular interfaces by creating ordered pi skeletons, incorporating different pore sizes, and engineering hydrophilic or hydrophobic channels. These synergically break through the adsorption energy barrier and promote inner-surface renewal, achieving a high removal rate for typical antibiotic contaminants (like levofloxacin) by BTT-DATP-COF, compared with BTT-DADP-COF and BTT-DAB-COF. The experimental and theoretical calculations reveal that such functional basis engineering enable the hole-driven levofloxacin oxidation at the interface of BTT fragments to occur, accompanying with electron-mediated oxygen reduction on terphenyl motif to active radicals, endowing it facilitate the balanced extraction of holes and electrons. The synergetic regulation of the electronic structure and interfacial reaction of covalent organic frameworks (COF) for water purification remains a challenge. Here the authors propose that COFs materials possessing molecular interfaces with ordered pi skeletons, suitable pore size, and hydrophilic/hydrophobic channels synergically break through the adsorption energy barrier achieving high removal rates for micropollutants.

Environmental theoretical calculation for non-periodic systems-亚洲成人在线一二三四五六区

1706186130 — Tue, 23 Jan 2024 09:13:54 +0000

Li F, Borthwick AGL, Liu W. Environmental theoretical calculation for non-periodic systems. Trends in Chemistry [Internet]. 2023;5:410-414. 访问链接 Abstract

Environmental theoretical calculation aims to use computer simulation to assist in solving environmental problems. Herein, we present the guiding principles of environmental theoretical calculation for non-periodic systems. A summary is given of recent progress towards the use of environmental theoretical calculation to reveal the degradation/transformation mechanisms of contaminants in reactions.

Active Center Size-Dependent Fenton-Like Chemistry for Sustainable Water Decontamination-亚洲成人在线一二三四五六区

1706186130 — Tue, 23 Jan 2024 08:24:02 +0000

Wu Z, Xiong Z, Liu W, Liu R, Feng X, Huang B, Wang X, Gao Y, Chen H, Yao G, et al. Active Center Size-Dependent Fenton-Like Chemistry for Sustainable Water Decontamination. Environmental Science & Technology [Internet]. 2023;57:21416-21427. 访问链接 Abstract

Accurately controlling catalytic activity and mechanism as well as identifying structure–activity–selectivity correlations in Fenton-like chemistry is essential for designing high-performance catalysts for sustainable water decontamination. Herein, active center size-dependent catalysts with single cobalt atoms (CoSA), atomic clusters (CoAC), and nanoparticles (CoNP) were fabricated to realize the changeover of catalytic activity and mechanism in peroxymonosulfate (PMS)-based Fenton-like chemistry. Catalytic activity and durability vary with the change in metal active center sizes. Besides, reducing the metal size from nanoparticles to single atoms significantly modulates contributions of radical and nonradical mechanisms, thus achieving selective/nonselective degradation. Density functional theory calculations reveal evolutions in catalytic mechanisms of size-dependent catalytic systems over different Gibbs free energies for reactive oxygen species generation. Single-atom site contact with PMS is preferred to induce nonradical mechanisms, while PMS dissociates and generates radicals on clusters and nanoparticles. Differences originating from reaction mechanisms endow developed systems with size-dependent selectivity and mineralization for treating actual hospital wastewater in column reactors. This work brings an in-depth understanding of metal size effects in Fenton-like chemistry and guides the design of intelligent catalysts to fulfill the demand of specific scenes for water purification.

Defect engineering-mediated Co9S8 with unexpected catalytic selectivity for heterogeneous Fenton-like reaction: Unveiling the generation route of 1O2 in VS active site-亚洲成人在线一二三四五六区

1706186130 — Tue, 23 Jan 2024 06:51:27 +0000

Fang Z, Qi J, Chen W, Zhang L, Wang J, Tian C, Dai Q, Liu W, Wang L. Defect engineering-mediated Co9S8 with unexpected catalytic selectivity for heterogeneous Fenton-like reaction: Unveiling the generation route of 1O2 in VS active site. Applied Catalysis B: Environmental [Internet]. 2023;338:123084. 访问链接 Abstract

Singlet oxygen (1O2) plays a crucial role in Fenton-like reactions due to its high efficiency and selectivity in removing trace organic pollutants from complex water matrices. Defect engineering, which allows the efficient exposure of active sites and optimization of electronic structures, has rapidly emerged as a fundamental strategy for enhancing 1O2 yield. Herein, we introduce tunable sulfur vacancy (VS) density into Co9S8 catalysts for peroxymonosulfate (PMS) activation. The modulation of the octahedral Co (CoS6) and tetrahedral Co (CoS4) electronic structures by VS triggers the unexpected selective generation of 1O2. The VS/PMS system exhibits excellent resistance to interference and highly selective degradation of electron-donating organic pollutants. Experimental and theoretical calculations revealed a new evolutionary route for 1O2 involving two phases (Phase I: HSO5− → *O, Phase II: *O + HSO5− →*OO → 1O2). This study provides a molecular-level understanding of VS-mediated catalytic selectivity for high-efficient decontamination applications.

The synergistic effect of radical and non-radical processes on the dephosphorization of dimethoate by vacuum ultraviolet: The overlooked roles of singlet oxygen atom and high-energy excited state-亚洲成人在线一二三四五六区

1706186130 — Tue, 23 Jan 2024 04:46:33 +0000

Liang J, Wu J, Gan P, Liu Y, Zhen P, Li Y, Zhao Z, Liu W, Tong M. The synergistic effect of radical and non-radical processes on the dephosphorization of dimethoate by vacuum ultraviolet: The overlooked roles of singlet oxygen atom and high-energy excited state. Water Research [Internet]. 2023;247:120775. 访问链接 Abstract

Organophosphorus pesticides are extensively utilized worldwide, but their incomplete dephosphorization poses significant environmental risks. This study investigates the dephosphorization of dimethoate (DMT), a representative organophosphorus pesticide, using a vacuum ultraviolet system. Surprisingly, in addition to hydroxyl radicals (•OH), non-radical processes such as photoexcitation and singlet oxygen atoms (O(1D)) exert more significant effects on DMT dephosphorization. The degradation kinetics of DMT demonstrate a perfect linear correlation with the radical yield in both UV-based and VUV-based advanced oxidation processes (AOPs), with greater efficacy of radical attack observed in the VUV system. This heightened efficiency is attributed to the excitation of DMT to a high-energy excited state induced by UV185 radiation. Additionally, •OH alone is inadequate for achieving complete dephosphorization of DMT. The Fukui index and singly occupied orbital (SOMO) analysis reveal that the O(1D) generated by UV185-induced photolysis of O2 exhibits exceptional selectivity towards P=S bonds, thereby playing an indispensable role in the dephosphorization process of DMT. This study highlights the significant contribution of non-radical pathways in DMT dephosphorization by VUV, which holds great implications for the advancement of photochemical-based AOPs.

High efficient PMS activation by synergistic effects of bimetallic sulfide FeS2@MoS2 for rapid OFX degradation-亚洲成人在线一二三四五六区

1706186130 — Tue, 16 Jan 2024 08:24:09 +0000

Tang J, Xu J, Zhang H, Liu W, Li H, Xia J, Xing X. High efficient PMS activation by synergistic effects of bimetallic sulfide FeS2@MoS2 for rapid OFX degradation. Chemical Engineering Journal [Internet]. 2023;475:146023. 访问链接 Abstract

Antibiotics have been widely used to treat bacterial diseases. Their wide spread in ecological environment will induce generation of antibiotic-resistant bacteria Therefore, it is critical to create an eco-friendly and effective approach for their removal. Herein, a bimetallic sulfide FeS2@MoS2 with rich sulfur vacancies (SVs) and high percentage of metallic 1T phase MoS2 was prepared by one-step solvothermal method to degrade ofloxacin (OFX) by activated peroxymonosulfate (PMS). FeS2@MoS2-1 (the mass ratio of Fe/Mo is 1) exhibited excellent performance for PMS activation, with 99.26% OFX removed in 20 min (0.2 g/L FeS2@MoS2-1, 0.2 mM PMS, initial pH). The degradation rate constant of kobs was 0.21 min−1 with FeS2@MoS2-1 system, which was about 4.88 and 22.91 times of FeS2/PMS and MoS2/PMS systems under the same experimental conditions respectively. In FeS2@MoS2-1, besides S2−, SVs would also accelerate Fe(III)/Fe(II) circulation through increasing the exposure of Mo(IV) active sites. Additionally, MoS2 transferred from the semi-conductive 2H phase to the metallic 1T phase, which could speed up electron transfer rate significantly. Quenching experiment and EPR test showed that SO4− and O2− were the main active oxygen species. Degradation pathway was proposed through the active sites identification by DFT calculations and intermediates detection by HPLC-MS analyzation. The results showed that OFX were vulnerable to be attacked and broke to form small molecular compounds through hydrogen loss, oxidative cracking, decarboxylation and demethylation four ways. In addition, their bio-toxicity was investigated and results showed that the toxic was diminished. This work indicated that the satisfactory universality, recyclability and stability enabled FeS2@MoS2-1 could be used as an efficient catalyst to activate PMS to degrade refractory organic pollutants in water.

Coupled Surface-Confinement Effect and Pore Engineering in a Single-Fe-Atom Catalyst for Ultrafast Fenton-like Reaction with High-Valent Iron-Oxo Complex Oxidation-亚洲成人在线一二三四五六区

1706186130 — Tue, 16 Jan 2024 08:20:39 +0000

Huang B, Wu Z, Wang X, Song X, Zhou H, Zhang H, Zhou P, Liu W, Xiong Z, Lai B. Coupled Surface-Confinement Effect and Pore Engineering in a Single-Fe-Atom Catalyst for Ultrafast Fenton-like Reaction with High-Valent Iron-Oxo Complex Oxidation. Environmental Science & Technology [Internet]. 2023;57:15667-15679. 访问链接 Abstract

The nanoconfinement effect in Fenton-like reactions shows great potential in environmental remediation, but the construction of confinement structure and the corresponding mechanism are rarely elucidated systematically. Herein, we proposed a novel peroxymonosulfate (PMS) activation system employing the single Fe atom supported on mesoporous N-doped carbon (FeSA-MNC, specific surface area = 1520.9 m2/g), which could accelerate the catalytic oxidation process via the surface-confinement effect. The degradation activity of the confined system was remarkably increased by 34.6 times compared to its analogue unconfined system. The generation of almost 100% high-valent iron-oxo species was identified via 18O isotope-labeled experiments, quenching tests, and probe methods. The density functional theory illustrated that the surface-confinement effect narrows the gap between the d-band center and Fermi level of the single Fe atom, which strengthens the charge transfer rate at the reaction interface and reduces the free energy barrier for PMS activation. The surface-confinement system exhibited excellent pollutant degradation efficiency, robust resistance to coexisting matter, and adaptation of a wide pH range (3.0–11.0) and various temperature environments (5–40 °C). Finally, the FeSA-MNC/PMS system could achieve 100% sulfamethoxazole removal without significant performance decline after 10,000-bed volumes. This work provides novel and significant insights into the surface-confinement effect in Fenton-like chemistry and guides the design of superior oxidation systems for environmental remediation.

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification-亚洲成人在线一二三四五六区

1706186130 — Tue, 16 Jan 2024 08:17:13 +0000

Wu Z, Huang B, Wang X, He C-S, Liu Y, Du Y, Liu W, Xiong Z, Lai B. Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification. Environmental Science & Technology [Internet]. 2023;57:14046-14057. 访问链接 Abstract

Precisely identifying the atomic structures in single-atom sites and establishing authentic structure–activity relationships for single-atom catalyst (SAC) coordination are significant challenges. Here, theoretical calculations first predicted the underlying catalytic activity of Fe–NxC4–x sites with diverse first-shell coordination environments. Substituting N with C to coordinate with the central Fe atom induces an inferior Fenton-like catalytic efficiency. Then, Fe-SACs carrying three configurations (Fe–N2C2, Fe–N3C1, and Fe–N4) fabricate facilely and demonstrate that optimized coordination environments of Fe–NxC4–x significantly promote the Fenton-like catalytic activity. Specifically, the reaction rate constant increases from 0.064 to 0.318 min–1 as the coordination number of Fe–N increases from 2 to 4, slightly influencing the nonradical reaction mechanism dominated by 1O2. In-depth theoretical calculations unveil that the modulated coordination environments of Fe-SACs from Fe–N2C2 to Fe–N4 optimize the d-band electronic structures and regulate the binding strength of peroxymonosulfate on Fe–NxC4–x sites, resulting in a reduced energy barrier and enhanced Fenton-like catalytic activity. The catalytic stability and the actual hospital sewage treatment capacity also showed strong coordination dependency. This strategy of local coordination engineering offers a vivid example of modulating SACs with well-regulated coordination environments, ultimately maximizing their catalytic efficiency.

The overlooked role of UV185 induced high-energy excited states in the dephosphorization of organophosphorus pesticide by VUV/persulfate-亚洲成人在线一二三四五六区

1706186130 — Tue, 16 Jan 2024 04:28:36 +0000

Liu Y, Wu J, Cheng N, Gan P, Li Y, Liu W, Ye J, Tong M, Liang J. The overlooked role of UV185 induced high-energy excited states in the dephosphorization of organophosphorus pesticide by VUV/persulfate. Chemosphere [Internet]. 2023;334:138993. 访问链接 Abstract

Vacuum ultraviolet (VUV) based advanced oxidation processes (AOPs) recently attracted widespread interests. However, the role of UV185 in VUV is only considered to be generating a series of active species, while the effect of photoexcitation has long been overlooked. In this work, the role of UV185 induced high-energy excited state for the dephosphorization of organophosphorus pesticides was studied using malathion as a model. Results showed malathion degradation was highly related to radical yield, while its dephosphorization was not. It was UV185 rather than UV254 or radical yield that was responsible for malathion dephosphorization by VUV/persulfate. DFT calculation results demonstrated that the polarity of P-S bond was further increased during UV185 excitation, favoring dephosphorization while UV254 did not. The conclusion was further supported by degradation path identification. Moreover, despite the fact that anions (Cl-, SO42- and NO3-) considerably affected radical yield, only Cl- and NO3- with high molar extinction coefficient at 185 nm significantly affected dephosphorization. This study shed light on the crucial role of excited states in VUV based AOPs and provided a new idea for the development of mineralization technology of organophosphorus pesticides.

Removal of Phenols by Highly Active Periodate on Carbon Nanotubes: A Mechanistic Investigation-亚洲成人在线一二三四五六区

1706186130 — Tue, 16 Jan 2024 04:06:20 +0000

Peng J, Zhou P, Zhou H, Huang B, Sun M, He C-S, Zhang H, Ao Z, Liu W, Lai B. Removal of Phenols by Highly Active Periodate on Carbon Nanotubes: A Mechanistic Investigation. Environmental Science & Technology [Internet]. 2023;57:10804-10815. 访问链接 Abstract

Carbon nanotubes (CNTs) and their derivatives have been widely exploited to activate various oxidants for environmental remediation. However, the intrinsic mechanism of CNTs-driven periodate (PI) activation remains ambiguous, which significantly impedes their scientific progress toward practical application. Here, we found that CNTs can strongly boost PI activation for the oxidation of various phenols. Reactive oxygen species analysis, in situ Raman characterization, galvanic oxidation process experiments, and electrochemical tests revealed that CNTs could activate PI to form high-potential metastable intermediates (CNTs–PI*) rather than produce free radicals and 1O2, thereby facilitating direct electron transfer from the pollutants to PI. Additionally, we analyzed quantitative structure–activity relationships between rate constants of phenols oxidation and double descriptors (e.g., Hammett constants and logarithm of the octanol–water partition coefficient). The adsorption of phenols on CNT surfaces and their electronic properties are critical factors affecting the oxidation process. Besides, in the CNTs/PI system, phenol adsorbed the CNT surfaces was oxidized by the CNTs–PI* complexes, and products were mainly generated via the coupling reaction of phenoxyl radical. Most of the products adsorbed and accumulated on the CNT surfaces realized phenol removal from the bulk solution. Such a unique non-mineralization removal process achieved an extremely high apparent electron utilization efficiency of 378%. The activity evaluation and theoretical calculations of CNT derivatives confirmed that the carbonyl/ketonic functional groups and double-vacancy defects of the CNTs were the primary active sites, where high-oxidation-potential CNTs–PI* were formed. Further, the PI species could achieve a stoichiometric decomposition into iodate, a safe sink of iodine species, without the generation of typical iodinated byproducts. Our discovery provides new mechanistic insight into CNTs-driven PI activation for the green future of environmental remediation.