Heterogeneous Fenton-like Reaction Research Articles

Electrochemical activation of peroxymonosulfate facilitated by a stainless-steel scrubber cathode: Transition from non-radical to radical pathway mediated by iron leaching

This study investigated the feasibility and underlying mechanisms of peroxymonosulfate (PMS) activation by a stainless-steel scrubber (SSS) cathode. Experimental findings revealed that the system could achieve 100 % degradation of sulfamethoxazole (SMX) in 30 min at initial pH value ranging from 3 to 9. The activation mechanism was observed to occur in two distinct stages. The first stage was characterized by a non-radical 1O2 dominance (0–6 min), where the activation of PMS and O2 was primarily facilitated through direct electron transfer at the cathode surface. Subsequently, the second stage transitioned to a radical dominance (6–18 min), with SO4− playing a pivotal role. This was attributed to the release of Fe2+ ions resulting from cathodic corrosion, which induced both homogeneous and heterogeneous Fenton-like reactions. The PMS/SSS cathode system exhibited anti-interference against most water matrices, except for HCO3−. Notably, the system demonstrated exceptional performance in the degradation of pollutants within phosphate wastewater samples, suggesting its potential for application in such contexts. In addition, the electrical energy was calculated to be 0.025 kWh·m−3 at a current of 0.01 A and a voltage of approximately 2.0 V, providing significant economic benefits.

Boosted adsorption and oxidation performances in peroxymonosulfate (PMS)-based heterogeneous fenton-like reactions via P, N co-doping strategy

The heterogeneous Fenton-like reactions (HTFR) have attracted considerable interest for their efficacy in degrading pollutants. However, the development of effective strategies for enhancing performance in HTFR remains a subject of ongoing research. Herein, a synergistic adsorption and oxidation-dominated process was developed to overcome the bottlenecks of peroxymonosulfate (PMS)-based HTFR in terms of mass transfer and catalyst reactivity. Heteroatom (P, N) co-doping for manganese (Mn) was employed to fabricate an efficient catalyst, Mn@5-NPC-800, which exhibited exceptional abilities of adsorption and PMS activation. The enhanced performance of HTFR was attributed to the increased specific surface area (SSA) and enhanced yields of graphitic-N/MnIII of the catalyst, which facilitated reactant enrichment and electron transfer in the delocalized conjugated area, respectively. The PMS-based HTFR induced by Mn@5-NPC-800 for pollutant removal was characterized by a synergistic adsorption and reactive oxygen species (ROS)-dominated oxidation process. DFT calculations revealed that the N, P co-doped carbon matrix (NPC) acted as a conductive bridge, significantly improving electron transfer between MnP and PMS molecule, which was identified as a key factor in governing the catalytic performance. The investigation presents a suggestive example of employing a doping strategy to create a synergistic effect of adsorption and oxidation, thereby strengthening the performance of Fenton-like reactions.

PH-dependent mechanisms of sulfadiazine degradation by natural pyrite-driven heterogeneous Fenton-like reactions

The development of a natural pyrite/peroxymonosulfate (PMS) system for the removal of antibiotic contamination from water represented an economic and green sustainable strategy. Yet, a noteworthy knowledge gap remained considering the underlying reaction mechanism of the system, particularly in relation to its pH sensitivity. Herein, this paper investigated the impacts of critical reaction parameters and initial pH levels on the degradation of sulfadiazine (SDZ, 3 mg/L) in the pyrite/PMS system, and elucidated the pH dependence of the reaction mechanism. Results showed that under optimal conditions, SDZ could be completely degraded within 5 min at a broad pH range of 3.0–9.0, with a pseudo-first-order reaction rate of >1.0 min−1. The low or high PMS doses could lower degradation rates of SDZ through the decreased levels of active species, while the amount of pyrite was positively correlated with the removal rate of SDZ. The diminutive concentrations of anions exerted minor impacts on the decomposition of SDZ within the pyrite PMS system. Mechanistic results demonstrated that the augmentation of pH levels facilitated the transition from the non-radical to the radical pathway within the natural pyrite/PMS system, while concurrently amplifying the role of •OH in the degradation process of SDZ. This could be attributed to the change in interface electrostatic repulsion induced by pH fluctuations, as well as the mutual transformation between active species. The stable presence of the relative content of Fe(II) in the used pyrite was ensured owing to the reduced sulfur species acting as electron donors, providing the pyrite/PMS system excellent reusability. This paper sheds light on the mechanism regulation of efficient removal of organic pollutants through pyrite PMS systems, contributing to practical application.

In Situ Synthesis of Cu2O Nanoparticles Using Eucalyptus globulus Extract to Remove a Dye via Advanced Oxidation.

Water pollution, particularly from organic contaminants like dyes, is a pressing issue, prompting exploration into advanced oxidation processes (AOPs) as potential solutions. This study focuses on synthesizing Cu2O on cellulose-based fabric using Eucalyptus globulus leaf extracts. The resulting catalysts effectively degraded methylene blue through photocatalysis under LED visible light and heterogeneous Fenton-like reactions with H2O2, demonstrating reusability. Mechanistic insights were gained through analyses of the extracts before and after Cu2O synthesis, revealing the role of phenolic compounds and reducing sugars in nanoparticle formation. Cu2O nanoparticles on cellulose-based fabric were characterized in terms of their morphology, structure, and bandgap via SEM-EDS, XRD, Raman, FTIR, UV-Vis DRS, and TGA. The degradation of methylene blue was pH-dependent; photocatalysis was more efficient at neutral pH due to hydroxyl and superoxide radical production, while Fenton-like reactions showed greater efficiency at acidic pH, primarily generating hydroxyl radicals. Cu2O used in Fenton-like reactions exhibited lower reusability compared to photocatalysis, suggesting deterioration. This research not only advances understanding of catalytic processes but also holds promise for sustainable water treatment solutions, contributing to environmental protection and resource conservation.

Hydrothermal Synthesis and Catalytic Activity of a Nanosized Fe2V4O13 Material in Heterogeneous Fenton-like Reaction for Degradation of Organic Compounds

In this research, the nanosized Fe2V4O13 complex oxide material was synthesized by the hydrothermal method. Its structure, morphology characterization, and other properties were determined using X-ray, SEM, EDX, and DTA-TG methods. The catalytic activity of the material was evaluated in terms of the decolorization and the degradation of the Indigo carmine dye. The optimal condition for the degradation and the reusability of the catalyst were determined. The results showed that the heterogeneous Fenton-like catalyst is a promise for wastewater treatment.

Unlocking the power of activated carbon-mediated peracetic acid activation for efficient antibiotics abatement in groundwater: Coupling the processes of electron transfer, radical production, and adsorption

The activation of peracetic acid (PAA) by activated carbon (AC) is a promising approach for reducing micropollutants in groundwater. However, to harness the PAA/AC system’s potential and achieve sustainable and low-impact groundwater remediation, it is crucial to quantify the individual contributions of active species. In this study, we developed a combined degradation kinetic and adsorption mass transfer model to elucidate the roles of free radicals, electron transfer processes (ETP), and adsorption on the degradation of antibiotics by PAA in groundwater. Our findings reveal that ETP predominantly facilitated the activation of PAA by modified activated carbon (AC600), contributing to ∼61% of the overall degradation of sulfamethoxazole (SMX). The carbonyl group (CO) on the surface of AC600 was identified as a probable site for the ETP. Free radicals contributed to ∼39% of the degradation, while adsorption was negligible. Thermodynamic and activation energy analyses indicate that the degradation of SMX within the PAA/AC600 system requires a relatively low energy input (27.66 kJ/mol), which is within the lower range of various heterogeneous Fenton-like reactions, thus making it easily achievable. These novel insights enhance our understanding of the AC600-mediated PAA activation mechanism and lay the groundwork for developing efficient and sustainable technologies for mitigating groundwater pollution. Environmental ImplicationThe antibiotics in groundwater raises alarming environmental concerns. As groundwater serves as a primary source of drinking water for nearly half the global population, the development of eco-friendly technologies for antibiotic-contaminated groundwater remediation becomes imperative. The innovative PAA/AC600 system demonstrates significant efficacy in degrading micropollutants, particularly sulfonamide antibiotics. By integrating degradation kinetics and adsorption mass transfer models, this study sheds light on the intricate mechanisms involved, emphasizing the potential of carbon materials as sustainable tools in the ongoing battle for clean and safe groundwater.

Activation of peroxymonosulfate by sludge-derived magnetic biochar for pollutant removal: Performance, applicability, and synergetic mechanism of iron species and carboxylated biochar

Developing eco-friendly, economical, and efficient catalytic systems for pollutant removal has become an imperative orientation in water treatment. Conversion of municipal sludge into multifunctional biochar has been considered as a feasible strategy for dual applicability in water treatment and sludge management. Herein, municipal biological and ferric sludge were recycled to synthesize an iron-based biochar (Fe4SBC1-800) with great magnetic separation performance (Ms = 29.96 emu g−1). The mixed sludge-derived biochar (Fe4SBC1-800) engaged as an efficient catalyst of peroxymonosulfate (PMS), which efficiently promoted the pollutants elimination including typical azo dye and several antibiotics and anti-inflammatory drugs. The enhanced degradation performance primarily originated from the formation of reactive radicals and non-radical species. The respective and synergetic mechanisms of biochar and supported iron species on PMS activation were verified based on experimental results and theoretical computations. The carboxyl groups served as the major active sites of biochar that donated electrons to PMS for •OH and SO4•− formation. The supported FeO species further boosted the activation capability: (i) the enhanced formation of radicals and FeIV = O via heterogeneous Fenton-like reactions; (ii) the promoted oxygen reduction for O2•− formation by promoting electron transfer from PMS to the FeO species through high sp2-hybridized biochar. Overall, this study innovatively proposed a sustainable and efficient activation system for PMS by iron-based magnetic biochar, which systematically probed the activation mechanism and reconsidered the role of the supported iron species in the iron-based biochar/PMS system.

Building the confined CoS2/MoS2 nanoreactor via interface electronic reconfiguration to synchronously enhance activity and stability of heterogeneous Fenton-like reactions

Herein, we synthesized CoS2/MoS2 catalysts with vertical interface structures to enhance peroxymonosulfate (PMS) activation. The characterization, experimental, and calculation results jointly reveal that the strong interface interaction (Co−S−Mo bond) regulates the electronic structure of CoS2/MoS2 to optimize the generation process of the main reactive oxygen species (SO4•−) and stabilizes the coordination structure of the active sites to greatly improve catalytic robustness. The unique interface structure of CoS2/MoS2 constructs the confined nanoreactor to adsorb pollutants and capture pollutant electrons,whcih can shorten the migration distance of SO4•− and improve the electron transfer rate, ultimately increasing the utilization and conversion rate of PMS. CoS2/MoS2 achieved outstanding activity (0.302 min−1), stability (93% of reactivity maintained after eight runs), and acid-base resistance (working pH range 3–11) for sulfamethazine degradation. This work provides a clear perspective for the rational design and optimization of interface engineering-mediated dual component catalysts in the Fenton-like reactions.

Synergistic redox and adsorption for enhanced Roxarsone removal: Heterogeneous Fenton-Like reaction with a novel composite of nanoscale zero-valent iron supported on γ-aluminum oxide

Roxarsone (ROX), a livestock growth enhancer, poses environmental and health hazards due to its remarkable stability, making traditional degradation methods ineffective. To tackle this issue, a novel Fenton-like composite, composed of nanoscale zero-valent iron supported on γ-aluminum oxide (nZVI/γ-Al2O3), was synthesized to boost ROX degradation. Results demonstrated nearly complete mineralization of the ROX organic matrix within just 180 min, facilitated by the Lewis acidity sites of γ-Al2O3. Significantly, this composite exhibited selective adsorption of released AsO43− ions on its surface, forming FeAsO4 and Fe-As-Al complexes. It also established an internal redox cycle involving Fe(0), Fe(II), and Fe(III), ensuring a continuous and efficient generation of primary reactive oxygen species (·OH and O2·−). Thus, a simultaneous redox process occurred on the composite surface can be attributed to the synergy of the reducibility of nZVI and the oxidation catalyzed by ·OH and O2·−. Initially, the nitro group of ROX was reduced by nZVI, forming more hydrophilic o-aminophenol, favoring subsequent oxidation and mineralization. Simultaneously, the As-C bonds in ROX were oxidized, yielding AsO43−, which was subsequently adsorbed over extended reaction times. This innovative approach offers a potential solution for treating wastewater contaminated with metalloid-organic composite pollutants, addressing the environmental and health concerns associated with ROX residues.

Coordination-Polymer-Derived Cu-CoO/C Nanocomposite Used in Fenton-like Reaction to Achieve Efficient Degradation of Organic Compounds.

In this paper, carbon-matrix-supported copper (Cu) and cobaltous oxide (CoO) nanoparticles were obtained by using coordination polymers (CPs) as a precursor. The aqueous solutions of copper methacrylate (CuMA) and cobalt methacrylate (CoMA) were preferentially prepared, which were then mixed with anhydrous ethanol to fabricate dual metal ion coordination polymers (CuMA/CoMA). After calcination under an argon atmosphere, the Cu-CoO/C nanocomposite was obtained. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the material has banded morphology, and the dual functional nanoparticles were highly dispersed in the carbon matrix. The prepared material was used in a heterogeneous Fenton-like reaction, with the aim of replacing traditional ferric catalysts to solve pH constraints and the mass production of ferric slime. The obtained nanocomposite showed excellent catalytic performance on the degradation of methylene blue (MB) at near-neutral conditions; the discoloration efficiency is about 98.5% within 50 min in the presence of 0.15 mmol/mL H2O2 and 0.5 mg/mL catalyst. And good reusability was verified via eight cycles. The plausible pathway for MB discoloration and the possible catalytic mechanism was also proposed.

Surface structure regulation of sulfidated zero-valent iron by H2O2 for efficient pH self-regulation and proton cycle to boost heterogeneous Fenton-like reaction for pollutant control

Sulfidated zero-valent iron (SZVI) has been widely used in controlling organic pollutants. However, the significant decrease in catalytic activity of SZVI-based Fenton-like systems under neutral and alkaline conditions remains a large problem. Herein, it was found that surface structure regulation of SZVI with H2O2 (HT-SZVI) greatly enhanced its reactivity and efficiently activated H2O2 to oxidize various organics in a wide pH range. The HT-SZVI/H2O2 system exhibited a pH self-regulation capability that stabilized the eventual solution pH at ∼3.5 at the initial pH of 3.0–9.0. The excellent oxidation performance was primarily attributed to surface-bound •OH produced from H2O2 activation by surface Fe(II) sites on HT-SZVI. Additionally, dissolved Fe(II) converted from surface Fe(II) induced proton generation to self-regulate pH. Newly formed high proton-conductive FeS and Fe3O4 shells accelerated the transfer of accumulated protons in solution to iron core to produce Fe(II), enabling efficient proton consumption-regeneration cycle and enhancing •OH production.

Tailoring the structural, optical, electrical and multiferroic properties of Sm1-xRxFeO3 (x = 0.0 and 0.5; R = Pr, Nd, and Gd) and their synergistic photocatalytic activity

In this work, nanocrystalline Sm1-xRxFeO3 (x = 0.0 and 0.5; RPr, Nd, and Gd) samples have been synthesized via auto-combustion method and characterized to understand their microstructural, optical, electrical and multiferroic properties. X-ray diffraction data in combination with the FTIR spectra revealed the monophase and distorted orthorhombic configuration of all the samples with Pbnm space group. Rietveld refinement displayed a reduction in the bond length as well as the bond angle in the Sm0.5Gd0.5FeO3 sample. Raman spectra exhibit compressive strain in Sm0.5Gd0.5FeO3 nanoparticles; this finding is further supported by the XRD analysis. UV–visible spectroscopy manifests a reduction in the optical energy bandgap on moving Gd to Pr in Sm0.5R0.5FeO3 system. Transmission electron microscopy (TEM) images in combination with energy dispersive x-ray (EDX) spectra reveal the non-uniform surface morphology with the agglomerated nature of nanoparticles and affirm the elemental compositions of all the samples. The room temperature P-E and M − H loops infer the multiferroic nature of all samples. Electron paramagnetic resonance (EPR) analysis divulges the weakening of the super-exchange interactions in Sm0.5R0.5FeO3 system. DC electrical resistivity measurements reflect semiconductor-like behaviour in all prepared samples. The dielectric behaviour of the samples is in accordance with the “universal dielectric response” model. The temperature-dependent dielectric measurements of all prepared samples have been performed at 1 kHz to determine the Néel temperature (TN). The photocatalytic investigation depicts the superior photocatalytic response of Sm0.5Pr0.5FeO3 nanoparticles under solar-light irradiation through the synergism of semiconductor-photocatalyzed oxidation and heterogeneous Fenton-like reaction.

Mineralization versus polymerization pathways in heterogeneous Fenton-like reactions

Fenton reaction has been widespread application in water purification due to the excellent oxidation performances. However, the poor cycle efficiency of Fe(III)/Fe(II) is one of the biggest bottlenecks. In this study, graphite (GP) was used as a green carbon catalyst to accelerate Fenton-like (H2O2/Fe3+ and persulfate/Fe3+) reactions by promoting ferric ion reduction and intensifying diverse peroxide activation pathways. Significantly, the carboxyl group on GP anchors iron ions to form GP-COOFe(III) which promote persulfate adsorption to form surface complexes and induce an electron transfer pathway (ETP). While the electron-rich hydroxyl and carbonyl groups will combine to from GP-COFe(II), a reductive intermediate to activate peroxide to generate free radicals (from H2O2 and PDS) or high-value iron [Fe(IV)] (from PMS). Consequently, different pathways lead to distinct degree of oxidation: i) radicals in H2O2/Fe3+/GP prefer to mineralize bisphenol A (BPA) with no selectivity; ii) Fe(IV) in PMS/Fe3+/GP partially oxidizes BPA but cannot open the aromatic ring; iii) ETP in PMS/ or PDS/Fe3+/GP drives coupling reactions to form polymeric products covered on catalyst surface. Thus, rational engineering surface functionality of graphite and selecting proper peroxides can realize on-demand selectivity and oxidation capacity in Fenton-like systems.

Degradation of residual xanthate in flotation tailing wastewater by activated H2O2 with natural ilmenite: A heterogeneous fenton-like reaction catalyzed at natural pH

Efficient treatment of residual xanthate from tailing wastewater has attracted soaring interesting recently. Herein, effect of activated H2O2 by natural ilmenite (FeTiO3) as a catalyst on sodium butyl xanthate (SBX) degradation was systematically investigated. More than 98 % SBX degradation efficiency was achieved by the method under optimal conditions (a natural pH = 8.7, [FeTiO3]0 = 4.0 g/L, [H2O2]0 = 2.0 mM, and [SBX]0 = 40.0 mg/L), and chemical oxygen demand (COD) removal rate was 85.41 %. Kinetic studies indicated that SBX degradation efficiency in FeTiO3-H2O2 system conformed with a pseudo first order kinetic equation. Also, comparative experiments indicated that this system degraded SBX was superior to the H2O2 alone and FeTiO3 alone systems. Reactive oxygen species (ROS) were determined by quenching experiments and electron paramagnetic resonance (EPR) tests, suggesting that OH and O2− were the primary reactive radicals in FeTiO3-H2O2 system. Cycling experiments and leaching metal ion tests suggested that FeTiO3 still exhibited high catalytic activity and excellent stability after five times of recycling. Finally, possible degradation pathways and mechanism of SBX in this system were proposed. Consequently, this study promotes the application of natural iron-based minerals as a catalyst in wastewater treatment, and provides new insights into the effective treatment of organic pollutants in tailing wastewater.

Efficient treatment of actual glyphosate wastewater via non-radical Fenton-like oxidation

Compared to radical oxidative pathway, recent research revealed that non-radical oxidative pathway has higher selectivity, higher adaptability and lower oxidant requirement. In this work, we have designed and synthesized Cu2O/Cu nanowires (CuNWs), by pyrolysis of copper chloride and urea, to selectively generate high-valent copper (CuIII) upon H2O2 activation for the efficient treatment of actual glyphosate wastewater. The detailed characterizations confirmed that CuNWs nanocomposite was comprised of Cu0 and Cu2O, which possessed a nanowire-shaped structure. The electron paramagnetic resonance (EPR) analysis, in situ Raman spectra, chronoamperometry and liner sweep voltammetry (LSV) verified CuIII, which mainly contributed to glyphosate degradation, was selectively generated from CuNWs/H2O2 system. In particular, CuI is mainly oxidized by H2O2 into CuIIIvia dual-electron transfer, rather than simultaneously releasing OH• via single electron transfer. More importantly, CuNWs/H2O2 system exhibited the excellent potential in the efficient treatment of actual glyphosate wastewater, with 96.6% degradation efficiency and chemical oxygen demand (COD) dropped by 30%. This novel knowledge gained in the work helps to apply CuNWs into heterogeneous Fenton-like reaction for environmental remediation and gives new insights into non-radical pathway in H2O2 activation.

Heterogeneous photocatalysis coupled with Fenton-Like reaction for fluoroquinolone antibiotics degradation by poly (Triazine Imide): From mechanism to application in a continuous flow catalytic system

The coupling of photocatalysis and heterogeneous Fenton-like reactions gains much interest as the possibility of synergy or enhanced effect between them, nevertheless, the development of catalysts and reaction systems are the main research focus for implementing the coupled technique for practical utilization. In this work, poly (triazine imide) (PTI), an ordered polymeric carbon nitride analogous to of g-C3N4, was firstly reported to be effective for activating peroxymonosulfate (PMS) to degrade micropollutants in a continuous flow catalytic system under visible light. Photogenerated charge separation and transfer occurred on {0001} facets of hexagonal PTI nanoplates, where binding of PMS molecules shortened the O-O bonds and elongated the O-H bonds of PMS, resulting in singlet oxygen (1O2) for the complete removal of antibiotics within 30 min. Besides, the immobilized PTI can maintain high degradation and mineralization rates of 96.8 % and 60.4 % respectively, after 8 h operation in a continuous flow reactor of laboratory scale size, and achieve a stable catalytic efficiency of 84.6 % for 1.7 L of wastewater in 48 h. This study provided an in-depth mechanistic understanding on coupling of photocatalysis and PMS activation, well addressed the problems of catalyst recycling, and validated the great potential of applying this coupled technique for environmental remediation.

Recycling waste iron-rich algal flocs as cost-effective biochar activator for heterogeneous Fenton-like reaction towards tetracycline degradation: Important role of iron species and moderately defective structures

Harvesting aquatic harmful algal blooms (HABs) and reusing them is a promising way for antibiotic degradation. Herein, a novel iron-rich biochar (Fe-ABC), derived from algal biomass harvested by magnetic coagulation, was successfully designed and fabricated as activator for heterogeneous Fenton-like reaction. The modification methods and pyrolysis temperatures (400–800 °C) were optimized to enhance the formation of rich iron species and moderately defective structure, yielding Fe-ABC-600 with enhanced electron transfer and H2O2 activation capability. Thus, Fe-ABC-600 exhibited superior removal efficiency (95.33%) on tetracycline (TC), where the presence of multiple iron species (Fe3+, Fe2+ and Fe4+) and moderately defective structure accelerating the Fenton-like oxidation. The concentration of leaching Fe after each reaction was all below 0.74 mg/L in five cycles, ensuring the sustained degradation. And •OH was proved to be the major radical contributing to the degradation of TC, as well as the direct electron transfer mechanism together, in which the CO acted as electron regulator and electron donor. Fe-ABC as a cost-effective catalyst has notable application potentials in TC removal from wastewater owing to its remarkable advantages of high resource utilization, enhanced catalytic property, high ecological safe, notable TC degradation efficiency, low cost and environmental-friendliness.

Defect engineering-mediated Co9S8 with unexpected catalytic selectivity for heterogeneous Fenton-like reaction: Unveiling the generation route of 1O2 in VS active site

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.

Directional and Ultrafast Charge Transfer in Oxygen-Vacancy-Rich ZnO@Single-Atom Cobalt Core-Shell Junction for Photo-Fenton-Like Reaction.

In photosynthesis, solar energy is harvested by photosensitizers, and then, the excited electrons transfer via a Z-Scheme mode to enzymatic catalytic centers to trigger redox reactions. Herein, we constructed a core-shell Z-scheme heterojunction of semiconductor@single-atom catalysts (SACs). The oxygen-vacancy-rich ZnO core and single-atom Co-N4 sites supported on nitrogen-rich carbon shell (SA-Co-CN) act as the photosensitizer and the enzyme-mimicking active centers, respectively. Driven by built-in electric field across the heterojunction, photoexcited electrons could rapidly (2 ps) transfer from the n-type ZnO core to the p-type SA-Co-CN shell, finally boosting the catalytic performance of the surface-exposed single-atom Co-N4 sites for peroxymonosulfate (PMS) activation under light irradiation. The synergies between photocatalysis and heterogeneous Fenton-like reaction lead to phenomenally enhanced production of various reactive oxygen species for rapid degradation of various microcontaminants in water. Experimental and theoretical results validate that the interfacial coupling of SA-Co-CN with ZnO greatly facilitates PMS adsorption and activation by reducing the adsorption energy and enhancing the cascade electron transfer processes for the photo-Fenton-like reaction.

Study on the synergistic effect of Cu(Ⅱ) and β-cyclodextrin in resin for efficient degradation of tetracycline by heterogeneous Fenton-like reaction

BackgroundTetracycline has been widely used to the treatment of diseases caused by bacteria. However, it was inevitably discharged into the water environment during the application process. How to effectively remove Tetracycline is a topic worth studying. MethodsHerein, a poly (chloromethyl styrene) based Cu(Ⅱ) and β-CD-doped resin named PS@PPDI-CDP-Cu(Ⅱ) made by a facile adsorption treatment was reported. The structure of PS@PPDI-CDP-Cu(Ⅱ) were characterized by SEM, XPS, and BET. The concentrate of Tetracycline was measured by a UV-visible spectrophotometer. Significant findingsIt was found that a higher catalytic ability was observed for PS@PPDI-CDP-Cu(Ⅱ) with a rate constant of 0.21 min−1 than Cu(Ⅱ) (0.05 min−1) due to the synergistic effect between Cu(Ⅱ) and β-CD, the whole progress was activated by NH2OH to form a more integral mechanism than that without NH2OH. Tetracycline could be efficiently degraded at a wide pH range from 3.24 to 9.25, PS@PPDI-CDP-Cu(Ⅱ) exhibited an excellent removal efficiency of 100% within 25 min and presented outstanding degradation efficiency over 6 reusable cycles. Compared with our previous work, PS@PPDI-CDP-Cu(Ⅱ) has the advantages of simple synthesis step, and the introduction of synergistic effect between Cu(Ⅱ) and β-CD makes it a better performance of Tetracycline degradation than PCMS@PPDI-CD.