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[Display omitted] • A magnetically recoverable 1 T-WS 2 /CuFe 2 O 4 composite was prepared for the first time. • The 1 T phase content in WS 2 was adjusted by controlling the heating temperature. • The WS 2 converted from solid spheres to hollow spheres with larger surface areas. • The reducing properties of WS 2 enabled the formation of an Fe and Cu redox system. • 1 T-WS 2 /CuFe 2 O 4 produced sulfur vacancies during use, which facilitated recycling. Transition metal sulfides are often used as cocatalysts to activate Peroxymonosulfate (PMS) in Fenton-like systems, but the problems include difficulties in recycling and the need to inject iron ions. In this paper, a self-synthesized magnetically recoverable heterogeneous 1 T-WS 2 /CuFe 2 O 4 composites was prepared for the first time via a two-step hydrothermal method, and the content of the 1 T phase in WS 2 was adjusted by controlling the hydrothermal temperature. Analytical techniques, such as XRD, Raman, SEM, TEM, BET, XPS, and VSM, showed that the composite catalyst was prepared with good particle shapes and high content of the 1 T phase. At the optimal dosage, this material activated PMS degraded to 93.6 % of 20 mg/L phenol in 50 min. The system exhibited high degradation efficiency, excellent interference resistance and good cycling stability under different conditions, and sulfur vacancies were generated during the process. ESR, quenching experiments, and other analyses confirm that SO 4 −, OH and 1O 2 are the main active species in the system, with 1O 2 making the greatest contribution. The degradation pathway of phenol was analyzed, and the formation of 12 intermediate products was qualitatively identified. Additionally, a simulation analysis of the toxicity of intermediate products was conducted. The degradation mechanism indicated that the three redox couples, Cu+/Cu2+, Fe2+/Fe3+ and W4+/W6+, provided synergistic activation of PMS. The self-synthesized 1 T-WS 2 /CuFe 2 O 4 composite showed high catalytic performance, good stability, a high magnetic recovery rate and a low ion leaching rate and shows promise for treating concentrated organic wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Cu-Ni@SBC catalyst was prepared by doping Cu-Ni bimetal in SBC. • The Cu-Ni bimetallic catalyst had a significant activation effect on H 2 O 2. • The synergistic catalytic mechanism in Fenton-like reaction was proposed. • The feasibility of the catalyst to degrade coal chemical wastewater was verified. In this study, the sewage sludge was converted into sludge biochar (SBC) and doped with Cu-Ni bimetal to synthesize a novel composite catalyst (Cu-Ni@SBC) for the activation of H 2 O 2 for phenol degradation. Characterization results showed that the Cu-Ni bimetal was successfully doped into the SBC and led to the formation of a porous structure with abundant cavities, resulting in a larger specific surface area and higher adsorbed oxygen content. Mechanism analysis revealed a valence state conversion cycle between Cu0-Cu(II), Ni(III)-Ni(II) and Cu-Ni which made Cu-Ni@SBC have higher electron transfer performance. Response surface methodology was applied to determine the optimal preparation and reaction conditions, under which the Fenton-like system composed of Cu-Ni@SBC and H 2 O 2 removed 100 % of phenol and mineralized 69.1 % of TOC from simulated wastewater. In addition, the experimental results showed that the Cu-Ni@SBC material had a relatively wide pH adaptation range (4–8), and the removal efficiency of phenol could reach 76.4 % after 5 cycles of experiments, and the catalytic inhibition rates of the two common coexisting anions, HCO 3 – and Cl-, were 17.1 % and 0 %, respectively. The results of practical application revealed that the phenol removal efficiency reached 90.44 % and the pollutant mineralization rate could reach 58.5 % within 90 min, which proved that the catalyst was suitable for the advanced degradation of organic matter in coal chemical wastewater. Therefore, Cu-Ni@SBC can be considered as a promising Fenton-like catalyst, and the process method is also of some guiding significance for the treatment of coal chemical wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen vacancy mediated L 2-x CO catalysts were designed via cation-deficiency. • A dual-reaction-center structure was formed by oxygen vacancy and ≡Cu(II) • Methyl group in phenolic increased electron transfer between dual-reaction-center. • DFT results showed that the O V enhanced H 2 O 2 adsorption and O-O stretching. • Catalytic mechanism and DMP decomposition path were investigated. The treatment of coal pyrolysis biochemical effluent has always been a serious problem in coal chemical process. However, improving the removal capacity of wastewater based on the characteristic of coal pyrolysis wastewater (CPW) has not been well investigated. In this work, the cation deficiency of Cu-based perovskite was used to couple with ≡Cu(II) to form dual-reaction-centers catalyst, which would improve the degradation of CPW in the heterogeneous Fenton-like system. According to the characterization, the La-deficiency could induce the generation of surface oxygen vacancy (O V) on the surface of L 2 CO perovskites, which would regarded as electron-rich center. Afterwards, ≡Cu(II) and dimethylphenol (DMP) were treated as electron-poor center and electron donor to accelerate electron transfer. The experimental results indicated that the L 1.8 CO sample achieved higher degradation activity than that of bulk L 2 CO sample for DMP degradation. The hydroxyl radical (∙OH) was the main function for the catalytic degradation of DMP. Significantly, the methyl group in phenolic pollutants could benefit to transfer electron in the electron-rich/poor reaction centers. Moreover, the density functional theory (DFT) calculation revealed that the introduction of surface O V would promote H 2 O 2 adsorption and strengthen electron transfer between H 2 O 2 and L 1.8 CO sample. Meanwhile, the DMP degradation pathways were also deduced by DFT calculation and UPLC-QTOF/MS analysis. The L 1.8 CO sample showed excellent recycling performance and catalytic stability during the heterogeneous Fenton-like process. This study developed a new perspective for designing more effective heterogeneous Fenton-like materials for CPW removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel PBAs/PMS Fenton-like system for organic pollutant degradation. • Modified oyster shell adsorbed metal ions and enhanced re-Fenton reaction. • FFM-PBA/PMS system showed high catalytic activity and adaptability for MB removal. • Active species and degradation pathway of MB were identified. Advanced oxidation processes extensively use Prussian blue analogs (PBAs) catalysts. However, metal-ion leaching limits their application in Fenton-like systems, causing environmental pollution and a decline in long-term performance. This study prepared a cubic iron–manganese bimetallic PBA catalyst by co-precipitation–calcination method. In the suspended flow experiment, under the optimal conditions, methylene blue (MB) was degraded by over 99.92 % within 90 min. The synergistic effect of iron–manganese bimetallic components and the degradation pathway of MB was proposed based on density functional theory (DFT) analysis and LC-MS results. In the recycling experiment, metal-ion leaching and catalyst structure damage significantly reduced the catalyst activity. To overcome the metal-leaching problem of PBA materials, a continuous-flow Fenton-like system was constructed. Cotton balls loaded with the iron–manganese bimetallic catalyst were connected to a calcined oyster shell fixed-bed reactor. In the 60 h continuous-inflow experiment, the average MB degradation rate of the effluent reached 95.81 %, which was 25.42 % higher than that of the single catalyst continuous-flow system. Experiments and characterization verified the mechanism of improving the reaction effect by using modified oyster shell. This shell can effectively adsorb the iron and manganese metal ions leached during the reaction, and these adsorbed metal ions further promoted the peroxymonosulfate (PMS) oxidation of MB through heterogeneous Fenton reaction, which was called re-Fenton reaction. This study provided a new strategy for the practical application of PBA catalysts in advanced oxidation processes. [ABSTRACT FROM AUTHOR]

• Nano-confined rGO/CuCo-MOF membrane was synthesized by stacked self-assembly. • Analyses confirmed the rGO membrane-confined growth of CuCo-MOF crystal. • Nano-confined membrane can achieve rapid destruction of organic pollutants. • The degradation path of OTC was proposed via DFT calculation and LC-MS analysis. Fenton-like processes generate reactive oxygen species (ROS) to achieve degradation of organic pollutants, however, practical water treatment processes suffer from low ROS utilization owing to its ultra-short lifetime and mass transfer limitations. To solve these problems, a nano-confined reaction space was designed to facilitate a fast mass transfer process for efficient removal of organic pollutants. Herein, the CuCo-based bimetallic organic framework (CuCo-MOF) was loaded in the water-transporting interlayer nanochannels of reduced graphene oxide (rGO) membrane. Membrane-confined CuCo-MOF with multiple exposed reaction sites activate peroxymonosulfate (PMS), generating ROS for ultrafast removal of oxytetracycline (OTC) at a water fluxes of 87.3 L·m−2·h−1. Notably, this membrane can continuously and stably degrade OTC (100 %) within 30 h. In addition, free radical capture experiments and EPR analysis indicated that the main ROS of the reaction system were singlet oxygen (1O 2) and sulfate radical (SO 4 −). Based on Fukui index results and LC-MS analysis, reaction sites of OTC attacked by ROS were identified and it's possible degradation pathways were proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bifunctional core–shell V O -LCO@CeO x nanoreactor was designed for H 2 O 2 activation. • Heterostructure boosted V O levels via the removal of oxygen atoms to interface. • Direct electron transfer between ≡Cu and ≡Ce achieved efficient ROS production. • The catalytic mechanism had been further confirmed through DFT calculations. Double oxygen vacancies (V O) tuned core–shell La V CuO δ @CeO x (V O -LCO@CeO x) nanoreactors with direct electron transfer (DET) structure was synthesized as an effective heterogeneous Fenton-like catalyst for the quinoline removal. The DET structure was constructed by electron-rich ≡Cu center of V O -LCO core and electron-capture center of CeO x shell for electrons supplying and consuming. This structure elevated total V O levels of catalyst through the removal of oxygen atoms in CeO 2 from attice to interface sites. Meanwhile, the ≡Ce(III) acted as reactive sites for the adsorption of hydrogen peroxide (H 2 O 2) to form surface peroxide species, and then the electron-rich ≡Cu center was further provided electrons to surface peroxide species by DET to produce hydroxyl radical. Moreover, the newly formed surface V O would also be further promote hydroxyl radical production through self-activation of H 2 O 2. This catalyst displayed excellent catalytic activity and stability. The density functional theory (DFT) results further pointed out that this structure had excellent adsorption energy, and generable electron transfer from V O -LCO to CeO x. This work provided a novel approach for the development of heterogeneous Fenton-like catalysts to degrade quinoline wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single atom Cu in the configuration of Cu-N 3 was anchored on hollow spherical g-C 3 N 4 to form SACu- hs CN. • The acetaminophen degradation activity of SACu- hs CN was superior to the sample of AGCu- hs CN with aggregated Cu particles via H 2 O 2 activation. • The SACu- hs CN/H 2 O 2 system degraded acetaminophen with a good durability. • 1O 2 unusually played a dominant role in degradation rather than the common OH radicals. Discharge of recalcitrant pharmaceuticals into aquatic systems has caused severe impacts on public health and ecosystem. Advanced oxidation processes (AOPs) are effective for eliminating these refractory pollutants, for which single-atom catalysts (SACs) become the state-of-the-art materials owing to the maximized exposure of active metal sites. In this work, hollow spherical graphitic carbon nitride (hs CN) was fabricated to incorporate copper species to develop Fenton-like catalysts for acetaminophen (ACT) removal. Through pyrolysis of supramolecular assemblies derived from melamine-Cu complex and cyanuric acid, single atom Cu-N 3 sites were anchored on hs CN by N-coordination to obtain SACu- hs CN. In virtue of the atomically dispersed Cu-N 3 sites as well as the hollow structure of hs CN providing smooth channels for the interactions between single Cu atoms and reactants, the optimal 5.5SACu- hs CN removed 94.8% of ACT after 180 min of Fenton-like reactions, which was superior to that of 5.5AGCu- hs CN with aggregated Cu particles on hs CN (56.7% in 180 min). Moreover, 5.5SACu- hs CN was still active after four cycles of regeneration. The mechanism investigation demonstrated that both hydroxyl radicals (OH) and singlet oxygen (1O 2) contributed to ACT degradation in 5.5SACu- hs CN/H 2 O 2 system, in which non-radical 1O 2 played the dominant role. [ABSTRACT FROM AUTHOR]

In this study, the effect of Mg 2+ and Cu 2+ on the oxidative degradation of Amoxicillin (AMX) by heterogeneous Fenton-like oxidation using nanoscale zero-valent iron (nZVI) as a catalyst was investigated. It was found that about 90.0% and 54.7% of AMX was degraded in the presence of 1 mM Cu 2+ and 1 mM Mg 2+ ions respectively, while 60.2% of AMX was removed by the control sample. Scanning electron microscopy (SEM) indicated that nZVI aggregated visibly after degradation of amoxicillin. X-ray photoelectron spectrometer (XPS) confirmed the reduction of Cu 2+ to Cu 0 by Fe 0 on nZVI’s surface to form similar Fe/Cu bimetal to accelerate the degradation of AMX, and magnesium oxides or hydroxides formed on the surface of nZVI to restrain the removal of AMX. X-ray diffraction (XRD) demonstrated the existence of Fe 0 in fresh nZVI and the corrosion aggregation of nZVI to form iron oxides or hydroxides after reaction. Kinetics studies demonstrated a pseudo first-order kinetics model for the oxidative degradation with the observed maximum K obs as 0.0867 min −1 in the presence of 1 mM Cu 2+ . The reason for this enhanced bimetallic catalytic activity is discussed. [ABSTRACT FROM AUTHOR]

• The types and properties of polyphenol-containing wastewaters are reviewed. • The treatment of polyphenol-containing wastewaters by Fenton reaction is reviewed. • The properties of several individual polyphenols are summarized. • The degradation of individual polyphenols by Fenton reaction is reviewed. • The reaction mechanisms of •OH with polyphenols are discussed. Polyphenols commonly exist in agro-industrial wastewaters, such as soft drink wastewater, cork wastewater, oil mill wastewater, landfill leachate, pulp mill wastewater, winery wastewater, and tannery wastewater. Polyphenols at high concentration tend to suppress or even eliminate the efficiency of biological wastewater treatment processes. Fenton/Fenton-like reactions as complementary treatments to biological processes have been reviewed in this article for the removal of polyphenols in the above wastewaters. Only a few researchers have taken advantage of the chelating and reducing properties of polyphenols and used polyphenol-containing wastewaters, such as cork wastewater and oil mill wastewater, to enhance the efficiency of Fenton/Fenton-like processes for the treatment of other contaminants. Some other researchers use individual polyphenols such as gallic acid, protocatechuic acid, and catechol as models of polyphenol-containing wastewaters. The treatment of these compounds by Fenton/Fenton-like reactions is also reviewed in this article. In the Fenton/Fenton-like processes, hydroxyl radical (•OH) is considered as the main species for decomposing polyphenols. The possible reaction mechanisms of •OH with polyphenols is discussed, as well as the reaction impact factors, including the number and position of hydroxyl groups in phenolic rings and the properties of other functional groups (electron-donating groups or electron-withdrawing groups). The •OH attack on phenolic compounds (e.g. phenol) in Fenton reaction can generate polyphenols, which, in turn, enhances the efficiency of Fenton process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The existence of γ-Fe 2 O 3 @CNTs can significantly increase the mass transfer efficiency. • A lot of hydroxyl radicals are generated on the surface of γ-Fe 2 O 3 @CNTs. • After 5 cycles, the mineralization efficiency of RhB remains at 92.55%. • The mineralization efficiency of RhB in γ-Fe 2 O 3 @CNTs/Mn@FNE-3DER system is more than 99.16% within 7 min. Three-dimensional electrochemical reactor (3DER) is an efficient technology for the treatment of printing and dyeing wastewater. The particle electrode between anode and cathode is the core unit of 3DER, which determines the treatment efficiency of wastewater. However, the deactivation of the particle electrode caused by the coverage of the catalytic sites seriously hindered the continuous operation of 3DER. In this work, γ-Fe 2 O 3 @CNTs particle electrode was prepared by immersion calcination, and its performance was evaluated by degradation of Rhodamine B (RhB) wastewater in 3DER. The study showed that in γ-Fe 2 O 3 @CNTs/Mn@FNE-3DER, the removal rate of RhB reached the best of 99.16% within 7 min under the conditions of γ-Fe 2 O 3 @CNTs dosage of 1.00 g·L-1, initial RhB concentration of 100 mg·L-1, pH 7.0, and current density of 20 mA·cm−2. The superior catalytic activity of the system is mainly due to the charge transfer channel in γ-Fe 2 O 3 @CNTs structure, which improves the mass transfer efficiency of electrons. According to LC-MS analysis, the degradation process of RhB can be divided into five stages: deethylation, chromophore cracking, debenzylation and deamination, ring opening and mineralization. Hydroxyl radicals play an important role in this process. After the reaction, most RhB is converted into CO 2 and H 2 O. In addition, the study also showed that the Fe3+/Fe2+ circulating system formed between the anode and cathode was the important reason for the high degradation efficiency of RhB. After five cycles of experiments, the degradation efficiency of 92.55% was still maintained, indicating that the particle electrode has significant stability and reusability in the catalytic process. To sum up, the excellent performance of γ-Fe 2 O 3 @CNTs particle electrode in three-dimensional electrochemical system provides a promising idea for the actual treatment of printing and dyeing wastewater. [ABSTRACT FROM AUTHOR]

The nano zero valent metals (nZVMs) of Fe, Cu, and Ni were prepared and examined in degradation of nonylphenol (6 mg L −1 ) by ultrasonic (20 kHz) assisted-Fenton-like process at the neutral pH, and the room temperature. The experiments were performed to investigate effects of irradiation time, H 2 O 2 dosage, and pH. In presence of 1.0 g L −1 of a solid catalyst, and 10 mM H 2 O 2 the degradation was complete after 15 min of sonication in presence of Fe 0 and Cu 0 ; while Ni 0 needed 25 min to do the same effect. Degradation is enriched in the presence of the catalyst and hydrogen peroxide, due to enhanced production of hydroxyl radicals at interfacial regions between cavitation bubbles and solid particles. Particle size and specific surface area of used catalysts have a major role. Results of total organic carbon removal supported the conclusion that the degradation of nonylphenol takes place through initial attack of the formed hydroxyl radicals to the side chain that decomposes in the form of gaseous products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Al3+ can significantly improve the electron transfer efficiency of the catalyst. • CAl 0.3 FO has excellent catalytic properties in the pH range of 3-11. • Fe-O-Al and Cu-O-Al bonds anchor metal ions and reduce metal ion leaching. • Radicals and non-radicals act synergistically. • Immobilized alginate/CAl 0.3 FO facilitates the realization of practical applications. The water pollution caused by the proliferation of tetracycline hydrochloride (TC) has seriously harmed human beings and the environment. Therefore, it is necessary to design a catalyst that can effectively remove TC and immobilize it for practical applications. Spinel catalysts can effectively resolve the problem of TC contamination in water. In this research, in order to solve the problems of poor dispersion, inferior performance and weak stability of copper ferrate (CuFe 2 O 4). Al3+-doped CuFe 2 O 4 was prepared by the one-step sol–gel-combustion method and used as a peroxymonosulfate (PMS) activator to promote the degradation of tetracycline (TC). A series of degradation experiments and characterization indicated that Al3+-doped CuFe 2 O 4 could remove more than 95 % of TC within 20 min, its first-order kinetic degradation constant was 2.5 times higher than that of CuFe 2 O 4. The mechanism by which Al3+ could improve the degradation of CuFe 2 O 4 may be as follows: the presence of Al3+ increased the electron transfer rate of the metal; effectively increased the specific surface area of the catalyst, provided more active sites; the Al-O-Fe and Al-O-Cu bonds generated by Al3+ immobilized the highly reactive metal ions, reducing ion leaching and improving the stability of the catalyst. Electron paramagnetic resonance and quenching experiments identified the synergistic effect of both radicals and non-radicals in the reaction. Electrochemistry and X-ray photoelectron spectroscopy (XPS) further verified the possible catalytic mechanism. Furthermore, by further immobilization, the 1 g of catalyst could continuously degrade 9 L of TC in water without stirring, showing excellent practical applications. This work provides a reference for improving the catalytic performance of ferrite spinel materials and solving the difficult problem of catalyst recovery in the real environment. [ABSTRACT FROM AUTHOR]

• CuCo-based MOF was prepared via a facile solvothermal method. • CuCo-MOF displays excellent activity for NIM degradation. • The synergy between the Cu-Co dual active centers enhanced the activation of PMS. • The NIM reaction site was revealed and its degradation path was proposed. • Cu and Co dual active sites to favor Cu and Co-PMS adsorption and charge transfer. Regulation of active sites is of significant importance for boosting the catalytic properties of metal–organic frameworks (MOF). Herein, we developed a one-pot strategy to construct bimetallic organic frameworks with Cu-Co double sites (CuCo-MOF) for peroxymonosulfate (PMS) activation. CuCo-MOF exhibits excellent active oxidation capacity, enabling complete removal of NIM within 25 min (0.227 min−1). Its NIM degradation rate was 7.3 and 2.4 times higher than that of Cu-MOF and Co-MOF, respectively. The theoretical simulations unravel that doping Co into the lattice structure of Cu-MOF promotes electron transfer from the electron-rich region (benzene ring) to the electron-deficient regions around metal sites, which facilitated the optimization of the adsorption energy for PMS activation and boosted the breakage of O O bond in PMS. According to LC-MS analysis and DFT calculation, the NIM degradation pathways were proposed, and its degradation intermediates were conducted for toxicity evaluation. The findings, revealing the synergistic effect of bimetals, open a new avenue for the rational design of highly efficient MOF-based Fenton-like catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sustainable and facile fabrication of collagen fibrous aerogels cross-linked by Fe (III) ions with silver nanoparticles. • Flexible AgNPs/Fe@CF aerogel exhibited excellent mechanical performance and softness. • Robust AgNPs/Fe@CF aerogel showed admirable efficiency for removal of antibiotic and ARB. • Reliable AgNPs/Fe@CF aerogel revealed effective adsorption ability for heavy metal ions. The development of antibacterial and catalytic adsorbents is an ideal strategy to simultaneously remove antibiotics, antibiotic-resistant bacteria, and heavy metal ions from wastewater. Herein, a porous and renewable aerogel was prepared as a lightweight adsorbent by using cost-efficient collagen fibers (CF) from the leather industry. Further, the complexes of Fe3+ ions with gallic acids modified silver nanoparticles (GA@AgNPs) were selected to sufficiently cross-link the hierarchical CF structure based on coordinated complexation, leading to good mechanical property of the resulted aerogel (AgNPs/Fe@CF). Benefiting from the incorporated AgNPs, AgNPs/Fe@CF aerogel exhibited high antibacterial activity against Tetracycline-resistant E. coli and Methicillin-resistant Staphylococcus aureus. Moreover, the cross-linked AgNPs could accelerate the redox cycle of Fe3+/Fe2+ by facilitating electron transfer and thus enhance the activation of peroxymonosulfate to produce more •OH and SO 4 •− radicals. Therefore, this AgNPs/Fe@CF aerogel demonstrated synergetic Fenton-like catalytic degradation efficiency for 5 different antibiotics (over 90 % within 30 min). In addition, abundant hydroxyl and carboxyl groups on collagen fibers endow desired capacity (greater than70 mg/g) to the porous aerogel, which is able to remove Cr (Ⅵ), Ni (Ⅱ), and Pb (Ⅱ). This study explores a new pathway for the construction of multifunctional aerogel materials for enhancing the purification of wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeO x nanoclusters decorated TiO 2 nanofibers (FeO x -TNFs) were fabricated for efficient photocatalytic Fenton-like norfloxacin degradation. • FeO x nanoclusters could enhance light absorption and accelerate separation of photogenerated carriers of TiO 2. • FeO x -TNFs catalyst leads to great enhancement in norfloxacin removal. The treatment of water pollution caused by antibiotic residues is essential for human health and the ecological environment. Herein, FeO x nanoclusters modified TiO 2 nanofibers (FeO x -TNFs) heterostructure was fabricated for efficient photocatalytic Fenton-like removal of antibiotic norfloxacin (NOR) under white LED irradiation. Compared with the pristine TiO 2 , the optimized FeO x -TNFs heterostructure displays much-increased photocatalytic Fenton-like activity, with NOR removal by 92 % within 5 h by visible-light-driven photocatalytic Fenton-like reactions. The efficient NOR degradation activity should be mainly ascribed to the extended optical light absorption in visible light region and accelerated separation and migration of photogenerated carriers of TiO 2 by the surface FeO x nanoclusters modification. This highly benefits the formation of reactive •OH radicals in Fenton-like reaction system and thus leads to great improvement in NOR removal. This study demonstrates an alternative approach of surface engineering to synthesize novel heterostructure for the effective photocatalytic remediation of wastewater containing antibiotic contaminants. [ABSTRACT FROM AUTHOR]

• The activation of H 2 O 2 by new CuII -NTA complex led to the degradation of SMX at neutral pH. • SMX degradation by CuII -NTA/H 2 O 2 process was enhanced in the presence of HA. • Hydroxyl radicals were found to be the major active species at pH 7. • Maximum degradation rates are achieved at pH ca. 7. Fenton process is among the most effective advanced oxidation process in wastewater treatment, but the necessity to work at acidic pH, in order to avoid metal precipitation, limits its large-scale application. In this work, a new Fenton-like process using copper(II)-nitrilotriacetic acid (CuII -NTA) complex as catalyst, was used for the activation of hydrogen peroxide (H 2 O 2) to degrade sulfamethoxazole (SMX) in aqueous medium under neutral pH conditions. The results showed that the CuII -NTA/H 2 O 2 process was not efficient in the degradation of SMX. The reason being that the generation of HO radicals is still limited by the extremely slow CuII -NTA/CuI -NTA redox cycle. Therefore, the combination of hydroxylamine (HA) accelerate the CuI recovery to induce the continuous production of HO radicals by the decomposition of H 2 O 2. It was evident that the steady-state CuI concentration in CuII-NTA/HA/H 2 O 2 process was much elevated than the CuII -NTA/H 2 O 2 process due to the quick regeneration of CuI -NTA complex by HA. Kinetic profiles were evaluated under a wide range of experimental conditions in order to assess the effects of the initial concentrations, working pH, Cu(II):NTA molar ratio and reaction temperature. The results showed that the degradation rates were enhanced with the increase of H 2 O 2 and CuII -NTA concentration during SMX oxidation. SMX was fully (83.64 %) degraded for an initial SMX concentration of 0.01 mM and an optimal Cu(II):NTA molar ratio of 1:1. Solution pH influenced SMX degradation and the highest degradation rate constant was achieved at pH 7.2. The radical scavenging experiments indicates that hydroxyl radical (HO) has major role for SMX degradation. The presence of metal ions such as MgII, CaII and MnII had no impacts or little inhibitory effect on the CuII -NTA complex catalyzed Fenton-like reaction, however, a complete degradation of SMX was achieved in the presence of FeIII ions. Also, the effects of various inorganic anions such as Cl−, SO 4 2−, NO 3 − and HCO 3 − on the oxidation efficiency of SMX were studied. The efficiency of mineralization of aqueous solution of SMX was evaluated by measuring total organic carbon (TOC). These results demonstrate that CuII -NTA catalyzed Fenton-like oxidation may be an efficient approach for remediation of wastewater containing antibiotics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green rust with high-speed electrons in multi-layer structure as high active sites. • Glucose-glucose oxidase system slowly releases appropriate amount of H 2 O 2 in situ. • FeIV=O is generated through the complexes between Fe(Ⅱ) and gluconic acid. • Diversified active agents have selective degradation at different reaction stages. Fenton reaction has been widely applied with fast reaction speed and strong oxidation capacity, but it also has some noticeable defects of acid-alkali reagents over-consumption and strong tendency of H 2 O 2 self-decomposition under high concentration. In order to overcome these shortcomings, this study proposed a green rust/Kaolin fixed glucose oxidase (GR/Glu-Kaolin@GOD) Fenton system. The production of H 2 O 2 from Glu-GOD@Kaolin system was catalyzed by GR to generate oxidizing species and degrade aniline organic wastewater. Results showed that the enzymatic reaction could produce H 2 O 2 at a gradual incremental pace in situ, avoiding active agent quenching and heightening its utilization rate. Furthermore, this system was proved to have an excellent removal effect under neutral and weak-acid conditions, which was superior to the traditional homogeneous Fenton with a narrow pH range. In this study, diversified active substances in the system were detected including hydroxyl radicals, FeIV=O and superoxide radicals, whose real-time degradation contribution changes were calculated and analyzed. On basis of the results, the roles of these active agents and the interactional principles among them were explored. Furthermore, the close correlation between Fe2+ in GR and GlcA and degradation mechanisms upon 3, 4-DMA were set forth in detail. Especially, in the middle and later stage of the reaction, the contribution of FeIV=O, generated through the complexes between Fe(Ⅱ) and GlcA, would continue to increase due to the gradually benign pH environment and FeIV=O gave full play to advantages in decarboxylating those intermediate products containing methyl, etc, which consequently enhanced both the oxidation efficiency and effluent biodegradability. In addition, the optimal operational conditions were determined through response surface data analysis. Moreover, the residual Glu and small molecular acids in the water could be fully exploited as suitable microbial carbon sources, and elevate the efficiency of the subsequent biological treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co/Mo co-catalyzed graphene sponge was prepared via impregnation pyrolysis method. • SCMG exhibited excellent catalytic performance and stability for PMS activation. • The enhanced performance was attributed to Co/Mo dual-site co-catalysis. • 1 O 2 and SO 4. - were the main ROS generated in SCMG/PMS. • Synergistic catalytic mechanism of SCMG was elucidated. A novel 3D Co/Mo co-catalyzed graphene sponges (SCMG) was fabricated by a simple impregnation pyrolysis method, and successfully applied as a highly efficient heterogeneous catalyst in peroxymonosulfate (PMS) activation for rapid and complete elimination of rhodamine B (RhB) within 2 min. The introduction of O contributed to enhanced electron transfer ability of the sponge, and 3D melamine sponges as substrates provided a highly dispersed support for Co/Mo heterojunction. MoS 2 co-catalysis accelerated Co(III)/Co(II) conversion and promoted the generation of 1 O 2 , which ensured an improved catalytic activity. The main reactive oxygen species in the SCMG/PMS system were 1 O 2 and SO 4. - , which contributed to a high reactivity over a wide range of pH (3–9). SCMG/PMS system were highly resistant to anions ( Cl - , SO 4 2 - and H 2 PO 4 -) and natural organic matter (humic acid), and could be widely used for the degradation of common organic contaminants. Besides, SCMG has good reusability and stability, and the metal leaching was well below existing safety standards over a wide pH range. This work broadens the application range of metal co-catalysis and provides a promising heterogeneous Fenton-like catalyst in refractory organic wastewater treatment. [ABSTRACT FROM AUTHOR]

• The definition, classification, and sources of polyphenols are provided. • The properties of polyphenols (reduction and chelation) on iron are presented. • The metal chelation activity of polyphenols is related to ortho -dihydroxy groups. • Polyphenols reduce Fe(III) to Fe(II) via a one-electron transfer pathway. • The application of polyphenols in Fenton/Fenton-like reactions is reviewed. Polyphenols are aromatic substances with one or more hydroxyl groups together with other substituents attached to aromatic rings. Polyphenols can be found in regular foods and drinks, including teas, coffee, vegetables, fruits, etc. Polyphenols have anti-oxidant, pro-oxidant, anti-histamine, anti-bacterial, anti-inflammatory, and anti-viral properties. They present chelation and reduction activities to iron ion and the anti-oxidant properties are mainly induced by the iron chelation effect. The metal chelation activity of polyphenols is primarily related to the presence of ortho -dihydroxy groups. Polyphenols can reduce Fe(III) to Fe(II) via a one-electron transfer pathway and they are oxidized to semiquinones. Due to the chelation and reduction properties, polyphenols are applied by researchers to promote the efficiency of Fenton/Fenton-like reactions for contaminant removal. The application of polyphenols in Fenton/Fenton-like reactions is reviewed in this article for the first time. The polyphenols reviewed include dihydroxybenzenes (such as catechol and hydroquinone), phenolic acids (such as gallic acid, protocatechuic acid, and tannic acid), flavonoids (such as catechin and epigallocatechin-3-gallate), and polyphenol extracts from tea, woods, coffee, etc. As a substance that pervades almost every aspect of human life, polyphenols present promising effect on the waste treatment in the environmental field, which deserves more studies. [ABSTRACT FROM AUTHOR]

Cu-doped BiO x composites were prepared with and without citric acid. In the presence of citric acid, Bi 0 and Cu 2+ /Cu + were confirmed to coexist in the composite (BiCu9/Bi 0 ) by X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst showed high Fenton activity and stability for the degradation and mineralization of 2-chlorophenol in the pH range of 6–8. H 2 O 2 was predominately converted into OH radicals in BiCu9/Bi 0 suspension, as assessed by the electron spin resonance technique. In the composite, Bi 0 inhibited the oxidation of H 2 O 2 by Cu 2+ into O 2 and OH by reducing Cu 2+ , enhancing the reaction of H 2 O 2 with Cu + to produce OH. Intermediate determination showed that 2-chlorophenol was decomposed mainly by OH radicals into hydroxylation products, subsequently decomposed into short-chain organic acids, and eventually decomposed into CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

In this study, the novel combination of Fe 3+ and FeS 2 /H 2 O 2 system was used to enhance the degradation of chloramphenicol (CAP) by promoting the synergetic effect between the Fe 3+ and the FeS 2 , and the kinetic models to elucidate the reaction mechanisms were validated. Raw pyrite samples were pretreated and characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy and Brunauer–Emmett–Teller surface area analyzer. Studies on the effects of buffer solution and phosphate on the kinetics of CAP degradation revealed that the autocatalytic effect was associated with the dissolution and generation of Fe 3+ . As confirmed by the experiment to examine the Fe 3+ mediated oxidation of FeS 2 , the catalytic improvement was due to the release of Fe 2+ by the reaction between the FeS 2 and the Fe 3+ at zero-order rate when the Fe 3+ was excessively present. Kinetic models including surface-controlled activation and homogeneous Fenton reactions were responsible for the degradation of CAP. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoFe 2 O 4 -CoO/nitrogen-doped carbon was first prepared from hydroxide/chitosan. • This composite had an enhanced activity in catalytic degradation of tetracycline. • The carbon support induced porous structure and higher electronic conductivity. • This catalyst had excellent stability and magnetic separability. • A possible catalytic mechanism was proposed. Developing a sustainable, efficient, and cost-effective heterogeneous catalyst for advanced oxidation processes is challenging in wastewater remediation. Herein, chitosan intercalated CoFe-layered double hydroxide was first employed as a precursor to fabricate a novel CoFe 2 O 4 -CoO/N-doped carbon composite (CoFe-LDO/NC) via a simple "in-situ coprecipitation-calcination" method. The resulting CoFe-LDO/NC was carefully characterized and employed to degrade tetracycline (TC) with the assistance of peroxymonosulfate (PMS). Under the optimum conditions (30 mg L−1 TC, 0.4 g L−1 catalyst, 0.4 g L−1 PMS, pH = 5), the degradation efficiency and mineralization degree reached 97.6% and 60.7% within 30 min, respectively. The superior activity of CoFe-LDO/NC was ascribed to its well-dispersed metal nanoparticles, large specific surface area (230.7 m2 g−1), hierarchical porous structure, and intensified electron transfer efficiency. The quenching test revealed that both the sulfate radicals and singlet oxygen were the dominant active species in the system. The degradation mechanism and TC evolution route were speculated by X-ray photoelectron spectroscopy and liquid chromatography-mass spectrometry. Escherichia coli growth inhibition test exhibited remarkable detoxification of TC solution after degradation. Moreover, CoFe-LDO/NC could be easily collected by magnetism, and 94.3% of its original activity was retained after five cycles. This work offers a green and scalable approach for the rational design of heterogeneous Co-based catalysts for degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of Mn x Co 1−x Se catalysts were synthesized via hydrothermal process. • Mn 0.5 Co 0.5 Se possessed excellent catalytic activity and reusability. • 1O 2 , •OH, and •O 2 – were the dominant ROS in Mn 0.5 Co 0.5 Se/H 2 O 2 system. • Ternary element cycling and selenium vacancies contributed to high activity. • Se-based Mn-Co bimetals were promising Fenton-like catalysts. In this study, the Mn x Co 1−x Se catalysts were synthesized and employed in Fenton-like reactions for the degradation of organic pollutants. The Mn 0.5 Co 0.5 Se composite with 1:1 dosing ratio (Mn:Co) represented the best catalytic performance and showed higher reusability and stability in five cycles. The optimum conditions for target pollutant removal were 0.1 g/L catalyst dosage, 2.6 mM H 2 O 2 concentration, and initial pH 7.0 according to the result of a response surface approach. The high catalytic efficiency of the Mn x Co 1−x Se catalyst was attributed to the high-performance cycle of Mn/Co/Se elements between their oxidic and reduced states. Both non-radical processes (based on 1O 2) and radical processes (based on •OH and •O 2 –) were verified to be involved in the degradation of Acid Orange 7 (AO7). Se vacancy on the Mn x Co 1−x Se surfaces was identified and it played a significant way in the generation of non-radical 1O 2. The AO7 degradation intermediates and toxicity analysis were also evaluated. This study provides new insights on the Se-based bimetal redox cycle in the Fenton-like process, promoting its application in organic pollutants degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Fenton-like catalyst, PWA/PAN, was prepared successfully. • TC was totally removed under optimal conditions in PWA/PAN/H 2 O 2 system. • TC removal efficiency and H 2 O 2 utilization were desirable in neutral pH. • PWA/PAN showed excellent catalytic activity and structural stability. Polyoxometalates (e.g., phosphotungstic acid) provide a new viewpoint for the development of efficient heterogeneous Fenton-like catalysts due to their distinct chemical structure and catalytic properties. In this work, a polymer composite (PWA/PAN) was successfully prepared by doping phosphotungstic acid (PWA) as an active component in the polyaniline (PAN) matrix. The prepared composite was then applied to degrade tetracycline (TC) in a Fenton-like system. Characterization results confirmed that PWA was dispersed in the inorganic carrier with its unique and stable Keggin-type structure, and the inherent chain structure of PAN did not change markedly. Compared with common heterogeneous Fenton-like catalysts, PWA/PAN displayed better catalytic activity for H 2 O 2 decomposition and TC removal. In the pH range of natural water (pH 6–11), PWA/PAN efficiently catalyzed H 2 O 2 decomposition. Under optimal conditions (20 °C, pH 0 7, catalyst dose of 0.5 g/L, and H 2 O 2 concentration of 50 mM), the degradation efficiency of TC and the decomposition efficiency of H 2 O 2 reached 100% and 0.1010 min−1 within 30 min, respectively. PWA/PAN exhibited excellent catalytic activity durability and structural stability. TC degradation efficiency by the PWA/PAN/H 2 O 2 system did not distinctly decrease. In addition, the degradation mechanism of TC in the PWA/PAN/H 2 O 2 system was revealed. Results disclosed that •OH was the main contributor to the degradation of TC, and it achieved most of mineralization of TC. This work is expected to tackle the common issues of easy deactivation, poor stability, and low H 2 O 2 decomposition efficiency of Fenton-like catalysts at neutral pH and provide novel materials for the treatment of antibiotic pollution. [ABSTRACT FROM AUTHOR]

Abstract: Membrane filtration was coupled with heterogeneous Fenton-like catalytic oxidation to resolve the continuously reuse problem of fine catalysts. A new integrated (MHF) reactor was developed to allow the active species to remain in the reaction system. The reactor consisted of a newly prepared heterogeneous catalyst, superfine Fe-immobilized carbon (FeOOH–C) particles, and a submerged ceramic micro-filtration membrane separator. Experimental results showed that the membrane module could efficiently intercept FeOOH–C particles in the reactor by the synergistic cooperative sieving of the raw and dynamic membranes. A relatively steady flux was maintained, but the magnitude of the flux was affected by the concentration of the FeOOH–C. In the MHF reactor, degradation of the targeted pollutant, acid orange II (AO II), occurred continuously and efficiently without an additional separation process to recover FeOOH–C. At a FeOOH–C dose of 1gL−1 and a residence time of 120min, the MHF reactor could keep a constant flux of 3Lm−2 min−1 with a stable degradation efficiency of ∼98% for 100mgL−1 AO II solution. The integrated process of membrane separation and heterogeneous Fenton-like catalytic oxidation was confirmed to be an efficient process for degradation of recalcitrant organic pollutants in wastewater. [Copyright &y& Elsevier]

[Display omitted] • A series of copper-based bimetallic oxides are synthesized. • Cu-Al 2 O 3 exhibits excellent Fenton-like catalytic activity and stability. • Selective H 2 O 2 conversion to OH · radicals is obviously enhanced. • The possible Fenton-like reaction mechanism is discussed. In this study, three copper-based bimetallic oxides (Cu-M, M: Al, Fe, and Zn) were prepared via a facile hydrothermal method and used as the catalyst for the Fenton-like process to degrade bisphenol A (BPA). Compared to other bimetallic oxides, Cu-Al bimetallic oxide exhibited excellent catalytic activity. The results of XRD, TEM, SEM, and EDS illustrated that Cu-Al was synthesized as CuAlO 2 /Al 2 O 3 (named Cu-Al 2 O 3) with a sponge-like structure. Nitrogen sorption isotherm showed that the Cu-Al 2 O 3 was consists of mesoporous with a high specific surface area and a narrow pore size distribution. FTIR spectra indicated the formation of a Cu − ligand complex between BPA and the surface Cu of the catalyst. 90% of BPA could be degraded within 90 min when adding 0.75 g/L (Cu-7.8 wt%) Cu-Al 2 O 3 catalyst and 12.5 mM H 2 O 2. Furthermore, it still kept over 70% removal efficiency after ten consecutive cycles, suggesting the superior stability of the catalyst. Based on the XPS and radical quenching experiments results, the Cu-Al 2 O 3 catalyst can not only improve the reduction of Cu2+ to Cu+ but also inhibit the oxidization of H 2 O 2 to generate O 2 - · radicals via the σ - C u l i g a n d c o m p l e x associated mechanism. Overall, this study indicates that Cu-Al 2 O 3 is a promising catalyst for the Fenton-like process. In addition, the strategy of the construction of the electron-rich catalytic site is an effective method to address the drawbacks of the classical Fenton process. [ABSTRACT FROM AUTHOR]

Abstract: The reactions involving green rusts (GRs), mixed ferrous–ferric oxides, remain poorly described relative to other iron oxides minerals which have been studied much more extensively. While the role of GRs in the reduction of chlorinated solvents and inorganic contaminants has been investigated, no work has appeared concerning the use of GR to promote Fenton reaction and oxidize organic pollutants. In this study, the catalytic ability of synthetic chloride green rust GR(Cl) was examined by employing the phenol as a model compound for the Fenton-like oxidation at neutral pH. For both tested concentrations of GR (5gL−1 and 10gL−1), rapid removal of phenol was observed when H2O2 was added. In GR water suspension, about 62% of phenol was mineralized after 24h in the presence of H2O2 (155mM) and GR (10gL−1), at pH 7. In GR/H2O2 system, HPLC analysis showed that phenol had been transformed after 1min mainly into catechol and hydroquinone, which corroborates with a Fenton reaction taking place in this system. [Copyright &y& Elsevier]

Heterogeneous activation of persulfate by Cu-hemin MOFs/BN under visible-light irradiation. • Bio-inspired hemin-MOFs supported on 2D boron nitride (BN) were successfully fabricated. • The Cu-hemin MOFs/BN composites with both Cu and Fe active sites showed an enhanced catalytic activity for PS activation. • Reaction conditions were optimized considering the effects of initial pH, catalyst concentration and PS dosage. • ESR analysis and quenching experiments revealed the SO 4 – and OH were responsible for the BPA degradation. The wide variety applications of Bisphenol A (BPA) have resulted in the world wide concerns because of its toxicity and estrogenic activity. Thus, it is critical to explore efficient method for the degradation of BPA. In this study, biomimetic metal-organic-frameworks (MOFs), composed of hemin as the organic linkage and copper ions as the nodes, supported on two-dimensional boron nitride (BN) have been fabricated via facile one-pot hydrothermal approach. The multifunctional Cu-hemin-MOFs/BN composites were applied to activate persulfate (PS) for the degradation of bisphenol A (BPA). Results showed that over 99% of BPA (40 mg/L) was degraded in 30 min under visible-light irradiation with a fast degradation kinetic (0.10 min−1). As compared with the traditional homogeneous catalysts, these Cu-hemin-MOFs based heterogeneous catalysts hold the advantages of high efficiency, easily separation, recycle and reuse without introducing secondary pollution. The BN not only acted as stabilizer to support the hemin-MOFs but also worked as adsorbents for the pre-concentration of the pollutants. Meanwhile, Cu-hemin-MOFs with dual active sites of the Fe and Cu were responsible for the PS activation, leading to the efficient degradation of BPA. Electron spin resonance (ESR) and radicals quenching experiments revealed the SO 4 – and OH were the main active radicals for the BPA oxidation. These findings indicated the synergistically combination of the hemin-MOFs with the 2D BN nanoplates endowed the composites with multifunctional properties, leading to the excellent catalytic activity for the oxidation of pollutants. This study provides new insights into the design and fabrication of novel MOF-based heterogeneous catalysts for the application in environmental remediation. [ABSTRACT FROM AUTHOR]