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A low-consumption water purification system is firstly constructed based on a new dual-reaction-center (DRC) catalyst molybdenum-doped zinc sulfide (Mo-ZnS, MZS) with a confined nonequilibrium surface. The extremely strong electron trapping ability of the Mo site is realized by the substitution of Mo for ZnS lattice. In this way, the electrons of emerging contaminants (ECs) are efficiently transferred to the nonequilibrium surface through the oriented interface process (Mo-S-Zn bond bridge), and obtained by the natural dissolved oxygen (DO) to generate hydrogen peroxide (H 2 O 2) under trace H 2 O 2 trigger without light and electricity assistant. The highest yield of H 2 O 2 is even up to ∼230 % of the initial value, and the ECs removal can reach 100 % within 60 min, which is far superior to conventional Fenton catalysts. This work realized the efficient utilization of the contaminant electrons through the construction of Mo-S-Zn bond bridge, which greatly reduced the energy consumption of water purification and improved the resourcefulness of ECs. [Display omitted] • DRC catalyst MZS with the confined nonequilibrium surface is first prepared. • MZS shows excellent performance for water purification. • Efficient H 2 O 2 generation is achieved without light and electricity assistant. • The highest H 2 O 2 concentration reaches up to ∼230 % of the initial concentration. • ECs electrons are efficiently utilized in ORR processes and water purification. [ABSTRACT FROM AUTHOR]

In the present work, direct ink writing (DIW) technology was utilized to fabricate geopolymer-based anisotropic membranes from metakaolin precursors. For evaluation of filtration performance in water treatment, the 3D-printed membranes were characterized, tested systematically, compared with a molded membrane and benchmarked against other geopolymer and ceramic membranes reported in the literature. With a novel approach, geopolymer-yttria stabilized zirconia (YSZ) ultrafiltration (UF) membrane with configuration of relatively dense rejection layer and gradient macroporous support was obtained via a one-step process of alkaline activation, DIW and curing, starting from a computer aided design (CAD) figure of an isotropic solid plate. The achievement of such structure resulted from the printing procedure leveraging both rheological properties of geopolymer ink and printing principle of DIW. The printed membrane displayed very high permeances (1453 L/(m2hbar) for pure water and 1311 L/(m2hbar) for suspension of 80-nm alumina particles), high rejection efficiency (98.4% for suspension of 80-nm alumina particles) and good chemical stability in alkaline solution. The present work provided the first-time report on additive manufacturing of geopolymer-based asymmetric UF membranes with superb performance for water treatment. [Display omitted] • Geopolymer-based membranes with anisotropic structures were fabricated from a process mainly comprising direct ink writing. • Ink rheological property and printing process were leveraged to achieve such configuration. • The produced membrane displayed high permeance and rejection efficiency in water treatment. • The first-time report on 3D printing of geopolymer-based asymmetric membranes was provided in this work. [ABSTRACT FROM AUTHOR]

Emerging single‐atom catalysts (SACs) are promising in water remediation through Fenton‐like reactions. Despite the notable enhancement of catalytic activity through increasing the density of single‐atom active sites, the performance improvement is not solely attributed to the increase in the number of active sites. The variation of catalytic behaviors stemming from the increased atomic density is particularly elusive and deserves an in‐depth study. Herein, single‐atom Fe catalysts (FeSA‐CN) with different distances (dsite) between the adjacent single‐atom Fe sites are constructed by controlling Fe loading. With the decrease in dsite value, remarkably enhanced catalytic activity of FeSA‐CN is realized via the electron transfer regime with peroxymonosulfate (PMS) activation. The decrease in dsite value promotes electronic communication and further alters the electronic structure in favor of PMS activation. Moreover, the two adjacent single‐atom Fe sites collectively adsorb PMS and achieve single‐site desorption of the PMS decomposition products, maintaining continuous PMS activation and contaminant removal. Moreover, the FeSA‐CN/PMS system exhibits excellent anti‐interference performance for various aquatic systems and good durability in continuous‐flow experiments, indicating its great potential for water treatment applications. This study provides an in‐depth understanding of the distance effect of single‐atom active sites on water remediation by designing densely populated SACs. [ABSTRACT FROM AUTHOR]

Abstract: Ag–AgBr was deposited onto mesoporous alumina (MA) and titanium-doped MA by a deposition–precipitation method. The photocatalytic activity and the dissolution of Ag+ from different catalysts were investigated during the photodegradation of 2-chlorophenol (2-CP) and phenol in ultrapure water and tap water with visible-light irradiation. With the increase in doped titanium, the Ag+ dissolution decreased with a decrease in the photocatalytic activity. Ag–AgBr/MA-Ti1 was considered the better catalyst for practical applications because its Ag+ dissolution was minimal (0.4mgL−1 in ultrapure water and 5μgL−1 in tap water), although its photoactivity was slightly less than that of Ag–AgBr/MA. The dissolution of Ag+ was related to a charge–transfer process based on the study of cyclic voltammetry analyses under a variety of experimental conditions. The results suggested that several types of anions in the water, including CO3 2−, SO4 2−, and Cl−, could act as electron donors that trap the photogenerated holes on Ag nanoparticles to facilitate electron circulation; this would decrease the release of Ag+. Our studies indicated that the catalyst had a higher activity and stability in water purification. [Copyright &y& Elsevier]

• The Fenton-like Cu-PAN 3 catalysts is first synthesized by co-precipitation and carbon thermal reduction method. • Dual reaction centers are constructed around graphene-like carbon and Cu species. • The pollutants as electron donors inhibit the ineffective decomposition of H 2 O 2 at the electron-poor centers. • The pollutant removal mainly relies on the surface cleavage at the electron-poor centers. High energy consumption has seriously hindered the development of Fenton-like reactions for the removal of refractory organic pollutants in water. To solve this problem, we designed a novel Fenton-like catalyst (Cu-PAN 3) by coprecipitation and carbon thermal reduction. The catalyst exhibits excellent Fenton-like catalytic activity and stability for the degradation of various pollutants with low H 2 O 2 consumption. The experimental results indicate that the dual reaction centers (DRCs) are composed of Cu-N-C and Cu-O-C bridges between copper and graphene-like carbon, which form electron-poor/rich centers on the catalyst surface. H 2 O 2 is mainly reduced at electron-rich Cu centers to free radicals for pollutant degradation. Meanwhile, pollutants can be oxidized by donating electrons to the electron-poor C centers of the catalyst, which inhibits the ineffective decomposition of H 2 O 2 at the electron-poor centers. This therefore significantly reduces the consumption of H 2 O 2 and reduces energy consumption. [Display omitted] [ABSTRACT FROM AUTHOR]

Excessive consumption of energy and resources is a major challenge in wastewater treatment. Here, a novel heterogeneous Fenton-like catalyst consisting of Cu-doped graphene-like catalysts (Cu-GCD NSs) was first synthesized by an enhanced carbothermal reduction of β-cyclodextrin (β-CD). The catalyst exhibits excellent Fenton-like catalytic activity for the degradation of various pollutants under neutral conditions, accompanied by low H 2 O 2 consumption. The results of structural characterization and theoretical calculations confirmed that the dual reaction centers (DRCs) were constructed on Cu-GCD NSs surface through C-O-Cu bonds supported on zero-valent copper species, which play a significant role in the high-performance Fenton-like reaction. The pollutants that served as electron donors were decomposed in the electron-poor carbon centers, whereas H 2 O 2 and dissolved oxygen obtained these electrons in the electron-rich Cu centers through C-O-Cu bonds, thereby producing more active species. This study demonstrates that the electrons of pollutants can be efficiently utilized in Fenton-like reactions by DRCs on the catalyst surface, which provides an effective strategy to improve Fenton-like reactivity and reduce H 2 O 2 consumption. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface microelectric fields (SMEF) on catalyst were formed by electrostatic force. • The formation of SMEF maximize the removal of refractory pollutants in wastewater. • The SMEF can link electron transfer between refractory pollutants and microorganisms. • The interspecific electron transport was induced by SMEF to can speed up degradation. The stable structure and toxic effect of refractory organic pollutants in wastewater lead to the problem of high energy consumption in water treatment technology. Herein, we propose a synergistic purification of refractory wastewater driven by microorganisms and surface microelectric fields (SMEF) over a dual-reaction-center (DRC) catalyst HCLL-S8-M prepared by an in situ growth method of carbon nitride on the Cu-Al 2 O 3 surface. Characterization techniques demonstrate the successful construction of SMEF with strong electrostatic force over HCLL-S8-M based on cation-π interactions between metal copper ions and carbon nitride rings. With the catalyst as the core filler, an innovative fixed bed bioreactor is constructed to purify the actual kitchen-oil wastewater. The removal efficiency of the wastewater even with a very low biodegradability (BOD 5 /COD = 0.33) can reach 60% after passing through this bioreactor. An innovative reaction mechanism is revealed for the first time that under the condition of a small amount of biodegradable organic matter, the SMEF induces the enrichment of electric active microorganisms (Desulfobulbus and Geobacter) in the wastewater, accelerates the interspecies electron transfer of intertrophic metabolism with the biodegradable bacteria through the extracellular electron transfer mechanism such as cytochrome C and self-secreted electron shuttle. The electrons of the refractory organic pollutants adsorbed on the surface of the catalyst are delocalized by the SMEF, which can be directly utilized by microorganisms through EPS conduction. The SMEF generated by electron polarization can maximize the utilization of pollutants and microorganisms in wastewater and further enhance degradation without adding any external energy, which is of great significance to the development of water self-purification technology. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, a novel metal-free catalyst consisting of multiporous oxygen-rich carbon–nitrogen graphene-like nanosheets (O LAA -CN NSs) is first developed through a staged temperature-programmed calcination of l -ascorbic acid (LAA)-modified dicyandiamide precursor. It is found that the oxygen species from l -ascorbic acid (O LAA) are introduced into the graphene-like basic matrix and replace partial N atoms to form the C O C-R structure, leading to the non-uniform distribution of electrons on the catalyst surface, and the formation of electron-rich centers around the C O C microareas according to a series of characterization techniques. As a result, O LAA -CN NSs exhibits excellent performance for refractory pollutant removal in the presence of peroxymonosulfate (PMS) and dissolved oxygen. Some pollutants with complex structures are even completely degraded within only 1 min. The interface reaction mechanism is further revealed that PMS mainly acts as an active inducer to drive the electron donation of pollutants over O LAA -CN NSs. These electrons are finally utilized by dissolved oxygen to generate reactive oxygen species (ROS) through the interface process. This reaction system results in pollutants that can either be cleaved directly by surface oxidation process or degraded by the attack of the generated ROS, such as singlet oxygen (1O 2) and superoxide radicals (O 2 •−), through oxygen activation, which significantly reduces the resource and energy consumption in advanced wastewater treatment by harnessing the energy of pollutants and dissolved oxygen in the water. [ABSTRACT FROM AUTHOR]

In common advanced oxidation processes, excess reagents and energy are often added to the reaction system to maintain the continuity of the reaction. These additions result in a large waste of resources and energy, which has become a bottleneck in the development of water treatment technology. In this study, we propose a new strategy to solve this problem based on a novel dual-reaction-center (DRC) Fe-ZnS quantum dots (Fe–ZnS QDs) catalyst that forms a non-equilibrium surface with an electron-polarized distribution. Through experimental and theoretical studies, it was verified that the activation of trace amounts of H 2 O 2 could break the energy barrier for pollutants to transfer electrons. The dissolved oxygen (DO) in the reaction system could be activated by gaining energy on the surface of the Fe–ZnS QDs catalyst, and was converted to 1O 2 to attack organic pollution. In addition, the pollutants themselves supplied electrons to H 2 O 2 through the surface of the Fe–ZnS QDs catalyst to generate more •OH radicals for pollutant degradation, thus providing two fast paths for pollutant degradation. The system could drive the reaction through a trace amount of H 2 O 2 , thereby activating DO to generate 1O 2 while effectively using the energy of pollutants. Therefore, the proposed system offers a new direction for the development of environmentally-friendly catalysts and greatly reduces the consumption of resources and energy. [Display omitted] • Fe–ZnS QDs is successfully developed as a Fenton catalyst for the first time. • The surface of ZnS QDs is regulated by trace Fe to form a non-equilibrium surface with an electron-polarized distribution. • The Fe–ZnS QDs/H 2 O 2 system exhibits excellent activity for pollutants degradation. • Inert oxygen species in reaction system are easily activated to 1O 2 to attack pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single-atom Fe, Co, and Cu on the supports with similar properties are synthesized. • Single-atom catalysts were efficient in degradation of the pollutants. • The durability of single-atom metal is in an order of Co − N 4 ≈ Fe − N 4 ≫ Cu − N 4. • Co(IV) = O was evidenced to be contribute predominantly to pollutant degradation. Single-atom metal catalyzed peroxymonosulfate (PMS) activation shows great potential in water treatment; and the activity of various metal centers have been explored. The properties of the support contribute significantly to the catalytic performance of the metal centers. The knowledge on the intrinsic distinctions of the elements in single-atom catalyzed PMS activation is, however, relatively in lack. In this work, via a facile one-step method, three representative elements of Fe, Co, and Cu were configured in a metal − N 4 structure and anchored on N-doped carbon matrix with similar composition and structure. The atomic dispersity of the metal centers was experimentally substantiated by electronic microscopic technique in atomic scale and X-ray absorption spectroscopy. All these single-atom metal centers exhibit high activity in PMS activation for selective degradation of the organic pollutants, while the durability of the single-atom metal centers is vastly distinct as examined in continuous flow-mode. The water treatment capacity is in an order of Co − N 4 ≈ Fe − N 4 ≫ Cu − N 4 for the elimination of 0.1 mM 4-chlorophenol from water. Based on the analysis of the qunching effect by various probe molecules and electron spin resonance spectra at various reaction conditions, the high-valent Co(IV) O species is proposed to be the predominant active species for pollutant degradation in Co − N 4 catalyzed PMS activation. The findings in this work sheds light on the desgin of efficent and durable single-atom catalyst for water treatment. [ABSTRACT FROM AUTHOR]

• Mesoporous reduction state cobalt species-doped silica nanospheres are first prepared. • Excellent activity is realized in mp -RSCo-SiO 2 NSs/H 2 O 2 system. • Efficient dual-pathway degradation of pollutant is achieved in Fenton-like process. • Pollutants replace H 2 O 2 as electron donors for the mp -RSCo-SiO 2 NSs system. • A new interfacial Fenton-like reaction mechanism involving pollutants is proposed. A novel heterogeneous Co-containing Fenton-like catalyst consisting of mesoporous reduction state cobalt (RSCo)-doped silica (SiO 2) nanospheres (mp -RSCo-SiO 2 NSs) was prepared by an enhanced hydrothermal process. The catalyst exhibited very high activity and stability for a series of refractory pollutant degradation in a very wide pH range of 3.1–10.9. The Fenton-like reaction rate constant of this Co-containing catalyst was approximately 290 times higher than that of Co 3 O 4 for pollutant degradation under the neutral and mild conditions. Based on the characterization, the catalyst possessed a porous nanosphere morphology, and the reduction state cobalt species, including nano-zero-valent cobalt (nZVCo) and Co2+, were found to be generated in the SiO 2 framework through forming Co O Si bonds. During the Fenton-like reaction, the electron donation effect of organic pollutants was successfully realized through the interaction of "Pollutants → Co2+/0-SiO 2 ". The obtained electrons from pollutants were transferred to the catalyst surface and captured by H 2 O 2 , resulting in the generation of hydroxyl radicals (OH). Therefore, a dual-pathway degradation of the pollutants was realized: (I) oxidation and degradation as the electron donors for the system and (II) attacking and destruction by OH radicals. This work provided a new perspective on the effective utilization of the electrons of pollutants and the improvement of Fenton reaction efficiency. [ABSTRACT FROM AUTHOR]

Single-atom Fe catalysis has exhibited remarkable potentials in water treatment applications. However, rational design of single-atom Fe catalysts with controlled catalytic performance is still challenging, due to the lack of the fundamental understanding on the corelated factors of structure, property, and catalytic behavior. Herein, PMS activation performance of the single-atom Fe sites is successfully boosted by molecular-engineering on the polymeric carbon nitride (CN) framework. Benzene-1,4-diamine regulates the polymerization process, and rises the ratio of carbon/nitrogen; the valence of the single-atom Fe is thereby positively shifted, leading to favorable thermal dynamics of the high-valent Fe(IV)=O involved oxidation reaction. The carbon-rich CN supported single-atom Fe catalyst thus exhibits remarkable performance in selective degradation of a series of organic pollutants via high-valent Fe(IV)=O oxidation pathway. The findings in this work implicate the significance of electronic properties of the support as one of the essential descriptors for a robust single-atom catalyst for pollutants abatement. [Display omitted] • Benzene diamine in precursor for synthesis of single-atom Fe catalyst could positively shift the valence of Fe center. • A 5.1 times of performance improvement in bisphenol A degradation reaction was realized. • The single atom Fe catalyst with optimized valence is durable in a fixed-bed reactor. • Theoretical simulation states that positive valence of Fe center lowered the energy barrier of the catalytic reaction. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Iodide was inserted in the interlayer of the multilayered Bi 2 WO 6 for better activity. • I 0.30 -Bi 2 WO 6 was highly effective for pollutants removal under visible light. • The enlarged layer spacing enhanced effective charge separation and transfer. • The main active species were holes whose oxidative power was enhanced after I− insertion. Abstract An iodine intercalated Bi 2 WO 6 was fabricated by a facile hydrothermal method (160 °C, 2 h) and characterized by field emission scanning electron microscope, high resolution transmission electron microscopy, nitrogen adsorption/desorption isotherms, X-ray diffraction and X-ray photoelectron spectroscopy, Fourier-transform infrared and UV-Vis diffuse reflectance spectra. The I 0.30 -Bi 2 WO 6 with an I/W molar ratio of 0.30 was highly effective for the degradation and mineralization of 2-chlorophenol, rhodamine B, bisphenol A, phenol, ciprofloxacin and sulfamethoxazole in water under visible light. Furthermore, the visible-light-driven photocatalytic activity of Bi 2 WO 6 was enhanced 3.1 times by the introduction of I−. The characterized results indicated that I− mainly inserted into the interlayer of Bi 2 WO 6 , expanding the layer spacing, favoring the efficient charge separation and transfer and prohibiting the recombination of the photogenerated electrons and holes. Specially, the XPS analysis indicated the I− ions substitued the absorbed oxygen to chemically bond in the layered Bi 2 WO 6 , resulting in the change of the electric charge distribution of Bi 2 WO 6. Moreover, the BET surface area was increased from 25.2 m2 g−1 for Bi 2 WO 6 to 66.7 m2 g−1 for I 0.30 -Bi 2 WO 6 for more surface active sites. In addition, the band gap was narrowed for expanded optical absorption in the visible light region. ESR and radicals trapping experiments verified holes were the main active species for the degradation of organic pollutants. Simultaneously, the more positive potential of valence band in iodine intercalated Bi 2 WO 6 could enhance the oxidative power of the photogenerated holes, resulting in the efficient removal of refractory organic pollutants in water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zero-added conversion of chicken manure into water treatment catalyst (RCM) is realized. • Electron-poor/rich microregions are successfully constructed on RCM. • Pollutant degradation processes can be driven by a little bit of peroxymonosulfate. • RCM has excellent performance on actual wastewater treatment. • Water treatment with low consumption is achieved by utilization of pollutants. Fecal pollution in rural areas and water pollution caused by emerging contaminants (ECs) are two international environmental problems. Here, we propose a new strategy to address the two problems simultaneously through the resource utilization and harmless transformation of poultry manure as a kind of water purification catalyst with zero addition. The ordered bonding of intrinsic metal-organic species is realized in the resourcelized procedure by a one-stage calcination-annealing method, which results in the formation of electron-rich/poor microregions. With the triggering of a small amount of peroxymonosulfate (PMS), the energy/electrons of ECs are utilized by the dissolved oxygen in water driven by the electron-rich/poor microregions on the catalyst surface. As a result, the system exhibits excellent performance in removing various ECs. The degradation rate can even be maintained above 94.3 % after 10,000 cycles. This work indicates a sustainable approach to the effective utilization and treatment of rural waste and pollutants. [ABSTRACT FROM AUTHOR]

A visible-light-driven photocatalyst AgBr@Ag/nitrogen-doped reduced graphene oxide (AgBr@Ag/N-RGO) was prepared by a hydrothermal- in situ oxidation method, and characterized by scanning and transmission electron microscope, X-ray diffraction, Fourier-transform infrared spectra, Raman and X-ray photoelectron spectroscopy. AgBr@Ag/N-RGO exhibited high photoactivity and photostability to degrade and mineralize various organic pollutants, as demonstrated with 2-chlorophenol, phenol, bisphenol A and diphenhydramine in water under visible light. Its photoactivity was 20, 5.3, and 2.9 times higher than that of Ag/N-RGO, TiO 2- x N x , and AgBr@Ag, respectively for the photodegradation of 2-chlorophenol. The characterized results verified that Ag nanoparticles (NPs) was first chelated by N-groups of N-RGO and then enwrapped by AgBr by in-situ oxidation, which was contributed to the enhancement of interfacial electron transfer in AgBr@Ag/N-RGO. Furthermore, the two charge transfer processes were elucidated that the plasmon-induced electrons on Ag NPs core transferred to AgBr shell, and could be further transferred away together with the photoexcited electrons on AgBr by N-RGO to interact with O 2 to form O 2 − , while the electrons of pollutants were accerelated to transfer to the plasmon-induced Ag NPs by the Ag-N complex along the π-π graphitic carbon network of N-RGO, which was responsible for the photoactivity and stability of AgBr@Ag/N-RGO. [ABSTRACT FROM AUTHOR]

• A novel surface-anchored photocatalytic nanofiltration membrane was fabricated. • A continuous flow-through process under visible light irradiation was involved. • It removes antibiotics in sewage effluent indiscriminately to more than 99%. • Good self-cleaning and biotoxicity reduction capacities were also fulfilled. • The usability of photocatalytic nanofiltration membrane is greatly improved. Bifunctional photocatalytic nanofiltration (PNF) membrane is increasingly concerned in practical micro-polluted water purification, but there are still several bottlenecks that inhibit its practicality. In this context, the feasibility of a novel metal-free and visible light-responsive surface-anchored PNF membrane for simultaneously removing target antibiotics in real sewage effluent in a continuous dynamic process was explored. The results showed that the optimal PNF-4 membrane was expectedly consisted of an inside tight sub-nanopore structured separation layer and an outside thinner, smoother, super hydrophilic mesoporous degradation layer, respectively. Consequently, the activated PNF-4 membrane could synergistically reduce trimethoprim and sulfamethoxazole concentrations to below two orders of magnitude, accompanying with almost constant high water permeability, suggesting that the hydrophilic modification of the mesoporous degradation layer basically offsets its inherent hydraulic resistance. Also, after repeating the fouling-physical rinsing process three times lasted for 78 h, only sporadic adherent contaminants remained onto the top surface, together with the minimal total and irreversible fouling ratios (as low as 7.2% and 1.2%, respectively), strongly demonstrated that PNF-4 membrane displayed good self-cleaning performance. Undoubtedly, this will significantly reduce its potential cleaning frequency and maintenance cost in long-term operation. Meanwhile, the acute and chronic biotoxicities of its permeate to Virbrio qinghaiensis sp. -67 were also reduced sharply to 2.22% and 0.45%, respectively. All of these evidences suggest that the dual functions of PNF-4 membrane are synergetic in an uninterrupted permeating process. It will provide useful insights for continuously enhancing the practicality and effectiveness of PNF membrane in actual micro-polluted water purification scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

A twofold cation-π-assembled catalyst consisting of honeycomb microsphere-like MoS 2 cross-linking g-C 3 N 4 hybrid (HM-MS/CN) is first developed to address the bottleneck of excessive resource and energy consumption in Fenton chemistry. A series of modern characterization techniques combined with theoretical calculation are used to reveal and verify the twofold cation-π interaction (Mo-O-C and Mo-S-C bonding bridges). It is found that the electrons of pollutants can be captured by H 2 O 2 and O 2 through the twofold cation-π interaction during Fenton-like reaction, which inhibits the oxidative decomposition of H 2 O 2 and promotes its hydroxylation. As a result, HM-MS/CN shows excellent performance for water purification by initiating pollutants as electron donors substituting H 2 O 2 consumption under mild natural conditions, and the actual consumption of H 2 O 2 in this system is only 6–8% of that in the common Fenton systems. This discovery is of great significance for the development of novel water purification technology with high efficiency and low consumption. [Display omitted] • A twofold cation-π-assembled catalyst consisting of HM-MS/CN is first prepared. • HM-MS/CN shows excellent performance for actual water purification. • The actual consumption of H 2 O 2 is only 6–8% of that in the common Fenton systems. • Twofold cation-π interaction based on Mo-O-C and Mo-S-C is responsible for excellent performance. • Pollutants act as electron donors substituting H 2 O 2 consumption via twofold cation-π. [ABSTRACT FROM AUTHOR]

Solid solution of BiOBr and BHO (BiO(OH) 0.06 Br 0.94 ) with abundant oxygen vacancies was supported on Ag/AgBr using precipitation and deposition–precipitation methods. The photocatalyst showed high and stable photocatalytic activity for the degradation of chlorophenols and azodyes in water under visible to NIR light irradiation without any release of Ag + , which came from visible-excited AgBr and the SPR of Ag NPs in the visible and NIR region. The different interfacial charge-transfer processes were verified on the basis of cyclic voltammetry analyses and all experimental information. The conduction band (CB) electrons of photoexcited AgBr reacted with the adsorbed oxygen forming O 2 •− , while the valence band (VB) holes of AgBr were transported the VB of BiO(OH) 0.06 Br 0.94 to oxidize organic pollutants or H 2 O to • OH. The plasmon-induced electrons from Ag NPs transferred to the CB of AgBr reacting with the adsorbed oxygen to O 2 •− , while the electrons trapped on the oxygen vacancies of BiO(OH) 0.06 Br 0.94 transferred to Ag NPs recombining with the plasmon-induced holes, inhibiting the release of Ag + , and the resulted VB holes of BiO(OH) 0.06 Br 0.94 oxidized organic compound. These interfacial charge transfers evidenced the high photoactivity and photostability of BiO(OH) 0.06 Br 0.94 /Ag/AgBr. [ABSTRACT FROM AUTHOR]

[Display omitted] • HA was efficiently mineralized in an Fe0-Fe y C z /Fe x -GZIF-8-rGO aqueous suspension. • The polar alkane-alcohol complex was formed with more single electrons on –OH group. • The polar alkane-alcohol complex enhanced its surface cleavage and •OH formation. • The reaction kinetics depends on the surface complex characteristic. Natural organic matter (NOM) has diverse negative impacts on water purification, however, preventing them occurrence very difficult. Herein, humic acid (10 mg/L), as the main component of NOM, is completely destructed within 120 min in the Fe0-Fe y C z /Fe x -GZIF-8-rGO air-saturated aqueous suspension without additional energy input, while its mineralization is followed by three kinetic constants within 480 min. During the process, HA was first complexed with Fe0-Fe y C z /Fe x -GZIF-8-rGO by π-π interaction and H-bonding interaction and cleaved to aromatic compounds and then to alkanes and alcohols with some small acids before 120 min. The electron paramagnetic resonance (EPR) analysis and density functional theory (DFT) calculations confirmed that a strongly polarized alkane-alcohol complex was formed after 150 min with an electron-rich hydroxyl group area in alcohol and an electron-poor alkane area. Moreover, the more electrons of alkane in the complex are delocalized and trapped by O 2 , with the adsorption of the alkane-alcohol complex on the catalyst surface based on the analyses of both electrochemical impedance spectroscopy (EIS) and chronoamperometry, greatly promoting the surface cleavage and hydrolytic process of alkane in the complex and producing more •OH for pollutant degradation than it does from the HA surface complex, which results in the highest mineralization rate in the period of 150–390 min. Our findings demonstrated that the current system is very promising for complex mixture-containing water purification without additional energy. [ABSTRACT FROM AUTHOR]

[Display omitted] • HA was efficiently mineralized in an Fe0-Fe y C z /Fe x -GZIF-8-rGO aqueous suspension. • The polar alkane-alcohol complex was formed with more single electrons on –OH group. • The polar alkane-alcohol complex enhanced its surface cleavage and •OH formation. • The reaction kinetics depends on the surface complex characteristic. Natural organic matter (NOM) has diverse negative impacts on water purification, however, preventing them occurrence very difficult. Herein, humic acid (10 mg/L), as the main component of NOM, is completely destructed within 120 min in the Fe0-Fe y C z /Fe x -GZIF-8-rGO air-saturated aqueous suspension without additional energy input, while its mineralization is followed by three kinetic constants within 480 min. During the process, HA was first complexed with Fe0-Fe y C z /Fe x -GZIF-8-rGO by π-π interaction and H-bonding interaction and cleaved to aromatic compounds and then to alkanes and alcohols with some small acids before 120 min. The electron paramagnetic resonance (EPR) analysis and density functional theory (DFT) calculations confirmed that a strongly polarized alkane-alcohol complex was formed after 150 min with an electron-rich hydroxyl group area in alcohol and an electron-poor alkane area. Moreover, the more electrons of alkane in the complex are delocalized and trapped by O 2 , with the adsorption of the alkane-alcohol complex on the catalyst surface based on the analyses of both electrochemical impedance spectroscopy (EIS) and chronoamperometry, greatly promoting the surface cleavage and hydrolytic process of alkane in the complex and producing more •OH for pollutant degradation than it does from the HA surface complex, which results in the highest mineralization rate in the period of 150–390 min. Our findings demonstrated that the current system is very promising for complex mixture-containing water purification without additional energy. [ABSTRACT FROM AUTHOR]

Layered structural BiOBr with {110} facet exposure is a promising functional material for highly selective adsorption and separation of heavy metal ions in water purification. In this study, the distinct adsorption behaviors of As(III), As(V), and Cr(VI) on {110} facet were theoretically and experimentally investigated. The results suggested that uncharged As(III) was dominantly adsorbed on the [Bi 2 O 2 ]2+ surface replacing the hydroxyl group, whereas Cr(VI) and As(V) oxyanions preferentially intercalated on {110} facet by exchange with Br- ions between the layers. Moreover, due to interfacial coupling configuration ([BiO-CrO 4 -OBi]-O-As(OH) 2) between the surface and interlayer on {110} facet, the synergic removal of Cr(VI) and As(III) could be accelerated under photoexcitation to induce a direct electron transfer from surface AsIII to interlayer CrVI, forming AsV and CrIII. Subsequently, approximately 69.3% of Cr(III) and 98.6% of As(V) were readily desorbed in acidic conditions and a high concentration of Br- solution, respectively, to achieve simultaneous detoxification and selective separation. [Display omitted] • Oxyanions (CrO 4 2- and HAsO 4 2-) preferentially intercalated between BiOBr layers by exchange with Br- ion. • Interfacial coupling configuration was constructed by the intercalated Cr(VI) and surface adsorbed As(III) on {110} facet. • Synergic removal was accelerated by electrons transfer from surface As(III) to interlayer Cr(VI) for both detoxification. • Selective separation of chromium and arsenic was based on interlayer anion-exchange property. [ABSTRACT FROM AUTHOR]

The effects of biological activated carbon treatment using Fe 2 O 3 -modified granular activated carbon in inhibiting antibiotic resistance genes in simulated drinking water distribution systems was compared with unmodified granular activated carbon as a reference. Fe 2 O 3 -modified biofiltration resulted in a sustained inhibition of resistance genes during drinking water chlorination and distribution (relative abundance in simulated tap water after the modified and unmodified filtration was 1.31% and 9.40%, respectively). A new electron transfer pathway occurring in attached biofilms on Fe 2 O 3 -modified granular activated carbon surface, which was identified using X-ray photoelectron spectroscopy and the phenanthroline spectrophotometric method, enhanced the extracellular electron transfer rate and weakened the pressure of organic micropollutants on microorganisms. Hence, the relative abundance of resistance genes (36.32%) and integron (8.79%) on modified carbon was considerably lower than that on unmodified carbon (115.59% and 13.85%, respectively). Meanwhile, the secreted extracellular polymeric substances on modified carbon presented higher flocculating efficiency and better mechanical stability, resulting in the suspended extracellular polymeric substances in downstream water exhibiting stronger electrostatic repulsion. The particle-attached biofilms in downstream distribution systems consistently failed to form larger aggregates, inhibiting horizontal gene transfer, and overall microbial metabolism. Based on network analysis, 11 OTUs in the water samples from raw water to simulated tap water formed an extremely interrelated module with no links to target resistance genes and integron. Therefore, a range of microbial variations triggered by the microbial interface on modified carbon successfully controlled the transfer of antibiotic resistance genes-associated risk from biological activated carbon effluent to tap water. Our findings revealed that enhancing the microbial interface using Fe 2 O 3 -modified granular activated carbon is a promising option for inhibiting the antibiotic resistance genes increase in tap water. [Display omitted] • Fe/granular activated carbon consistently suppressed antibiotic resistance genes. • Distinct extracellular electron transfer pathway weakened pollutants pressure. • The size of particle-attached biofilms during water distribution was limited. • An interrelated microbial module inhibited horizontal gene transmission. • Antibiotic resistance genes were controlled successfully by microbial interfaces. [ABSTRACT FROM AUTHOR]

• Co2+-N-C π is constructed via atomically dispersed Co bonding with C-based graphene-like structure. • Co2+-N-C π (Co−π) structure plays key role for PMS activation and pollutant degradation. • Electron donation effect of pollutants is realized through π-π interaction in SACo-NGs system. • High efficiency and low consumption are realized in SACo-NGs/PMS water treatment system. Orbital interaction involving metal cation−π is an important form for electron transfer regulation. To accelerate the interfacial electron transfer of peroxymonosulfate (PMS) activation for water treatment, we report a new strategy through bonding atomically dispersed cobalt with nanospheric C-based graphene-like structures (SACo-NGs) to form metal cation−π structure, driving rapid and directional transfer of the electrons of pollutants to PMS on the catalyst surface. The catalyst SACo-NGs is synthesized by an enhanced hydrothermal-sintering method and the formation of metal cation−π structure is demonstrated by X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR) and Raman spectroscopy. It is found that Co−π structures (Co2+-N-C π) play a key role for the efficient activation of PMS, which results in pollutants being greatly removed in a few minutes. During the reaction, pollutants can donate electrons for the system through π−π interaction accompanying by the direct oxidative degradation of pollutants. The obtained electrons are quickly transferred to the atomically dispersed cobalt sites through the formed cation−π structure, which promotes the activation of PMS. This is a successful practice in the field of PMS activation using cation−π structure to accelerate electron transfer and achieve rapid degradation of pollutants. [ABSTRACT FROM AUTHOR]

• Heterogeneous Fenton-like reaction was studied using a pilot scale test. • TCM, DCAA and TCAA were the main compositions of DBPs in drinking water. • C1-C5 and F1-F5 of NOM were the main precursors of different DBPs. • This treatment improved removal efficiency of DBPs and NOM without adjusting pH. • This treatment process also controlled the genotoxicity of drinking water. This paper explores the removal of natural organic matter (NOM) and disinfection by-products (DBPs) in drinking water by heterogeneous Fenton-like oxidation and granular activated carbon (GAC) filtration in a pilot scale test without adjusting pH of the water. pH of the used water in this study was from 7.5 to 8.7. Comparing with conventional water treatment processes, heterogeneous Fenton-like reaction and GAC filtration increased the removal rate of dissolved organic carbon (DOC), NOM with different apparent molecular weight (AMW) (F1-F7) and with different compositions (C1-C5) to 75.11%, 88.65% and 58.73%, respectively. Moreover, heterogeneous Fenton-like reaction and GAC filtration increased the removal rate of DBPs to 88.18%. The multivariate statistical analysis indicated that haloacetic acids (HAAs) and haloketones (HKs) mainly came from fulvic-like and humic-like NOM with AMW lower than 1.5 K Da. These substances with AMW between 1.5 K Da and 3.5 K Da were the main precursors of trihalomethanes (THMs). The main precursors of halonitriles (HANs) were soluble microbial byproduct-like (SMP-like), tyrosine-like and tryptophan-like substance with the AMW between 3.5 K Da and 4.5 K Da. Overall, without adjusting pH of water, heterogeneous Fenton-like reaction and GAC filtration improved the removal efficiency of NOM and DBPs, and controlled the genotoxicity of drinking water. [ABSTRACT FROM AUTHOR]

• Excellent activity for water purification is realized in cobalt-zinc ferrite/PMS system. • Surface oxygen vacancy induces PMS activation to generate •OH, SO 4 •− and H 2. • An efficient dual-pathway removal of pollutants is first achieved in PMS activation. • Pollutants replace PMS as electron donors for the V O -rich ZnFe 0.8 Co 0.4 O 2.4 system. • A novel solid-liquid interfacial reaction mechanism is proposed in PMS activation. Peroxymonosulfate (PMS) activation in heterogeneous processes for pollutant degradation is a promising water purification technology. However, the existed rate limiting step greatly restrains its performance and increases the consumption of PMS and energy. Herein, we offer a new strategy to solve this problem. In this work, surface oxygen vacancy (V O)-rich ZnFe 0.8 Co 0.4 O 2.4 nanoparticles were prepared and characterized, which exhibited high activity and stability for refractory pollutant degradation with PMS activation. It was found that PMS ([O 3 S O I O II H]−) could be adsorbed and trapped by the surface oxygen vacancies in the form of O I - Vo or O II - Vo during the reaction. Different electron transfer pathways from Vo to different O sites of PMS was realized in the solid-liquid interface based on the generation of OH, SO 4 − or H 2 from PMS reduction. Pollutants were predominantly adsorbed at metal Co sites in which their electrons were captured by metal species and then transferred to the surface oxygen vacancies, achieving efficient recycling of electrons in the aqueous suspensions. This system achieves a dual-pathway degradation of pollutants and electron transfer from pollutants to PMS to produce free radicals and H 2 , essentially changing the traditional concepts of pollutant removal and providing a sustainable strategy for pollutant utilization during water purification. [ABSTRACT FROM AUTHOR]

• Multiple vacancy associates were introduced by constructing porous β-Bi 2 O 3 -{220}. • Porous β-Bi 2 O 3 -{220} was highly effective for pollutants removal under visible light. • Multiple vacancy associates enhanced surface polarization for efficient charge separation. • The electron transfer from pollutants to the catalyst was promoted by their strong interaction. • HO 2 and holes were confirmed to be the main active species. Porous β-Bi 2 O 3 with highly exposed {220} facets was fabricated for the first time and the formation of surface multiple Bi-O vacancy associates was confirmed by the photoluminescence, positron annihilation spectra, and theoretical calculations. Compared with traditional nonporous β-Bi 2 O 3 -{201}, the photocatalytic rate of porous β-Bi 2 O 3 -{220} was more than twice faster and the photoconversion efficiency increased by 20 times. And various refractory organic pollutants can be effectively degraded and mineralized under visible light. Multiple Bi-O vacancy associates were demonstrated to change electronic structure and enhance the polarization of the related atoms and orbitals. The photogenerated charge separation and transfer was thus improved to produce more surface active species. Simultaneously, the electron transfer from pollutants to the catalyst was found to be accelerated, finally leading to the outstanding photocatalytic performances of porous β-Bi 2 O 3 -{220}. These findings provide useful insights into the development of visible-light-driven photocatalysts for water purification. [ABSTRACT FROM AUTHOR]