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• DFT calculations were used to guide the deprotonated BTA (BTA−) intercalated LDH interlayer. • LDH within PVDF/LDH@BTA− captured up to 0.26 mmol/cm2 of chloride ions through anion exchange. • Adsorption mechanism of Cl− into LDH interlayer was investigated by MD simulation and experimental demonstration. • PVDF/LDH@BTA− composite nanofibers significantly enhanced anticorrosion performance for epoxy. To enhance corrosion resistance and extend the service life of coatings, layered double hydroxides (LDH) have been embedded into coatings to create a hybrid of organic–inorganic micro/nano-containers, improving the coatings' physical barrier properties. Herein, an elaborately designed strategy is proposed to in-situ grow LDH on nanofibers, thereby obtaining polyvinylidene difluoride/hydrotalcite@deprotonated benzotriazole (PVDF/LDH@BTA−) composite nanofibers, followed by incorporation into an epoxy resin to formulate the composite coating. The even distribution of LDH within the coating, aided by nanofibers, significantly bolstered the coating's barrier effect. Upon exposure to corrosive environments, the hydrotalcite structure within PVDF/LDH@BTA− adsorbs chloride ions through anion exchange, capturing up to 0.26 mmol/cm2 of chloride ions. Concurrently, corrosion inhibitors were released, forming a protective layer on the copper surface to substantially mitigate the corrosion process. This innovative approach markedly enhances the composite coating's long-term corrosion resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • C-BiOCl makes the immanent Cl– in wastewater profitable for NH 4 +-N removal. • Internal electric field engineering accelerates photocatalytic RCS production. • C-BiOCl structural evolution benefits Cl– oxidation instead of H 2 O oxidation. • RCS generation rate from Cl– over C-BiOCl reaches 0.23 mg/L min−1. • NH 4 +-N removal efficiency of 95.6% is realized in treating landfill leachate. Utilizing the immanent salt (Cl–) in wastewater to generate reactive chlorine species (RCS) satisfies the future needs for sustainable, on-demand, and decentralized ammonia nitrogen (NH 4 +-N) removal. The microstructural evolution of bismuth oxychloride (BiOCl) photocatalyst under irradiation benefits for overcoming the competition between Cl– and H 2 O oxidation and achieving high N 2 selectivity. Herein, internal electric field (IEF) engineering by carbon doping is applied to promote photocatalytic RCS generation rate over BiOCl. The carbon dopant not only enhances the IEF intensity of BiOCl by a factor of 2.1 times for carrier dynamics promotion, but also improves Cl– oxidation against H 2 O oxidation. An RCS production rate of 0.23 mg/L min−1 is realized over carbon-doped BiOCl (C-BiOCl) through the accelerated interaction between lattice and environmental Cl–, which is twice that of the undoped BiOCl (0.11 mg/L min−1). The relation between IEF intensity and RCS generation rate over C-BiOCl manifests a correlation coefficient of 0.96. Effective NH 4 +-N degradation with N 2 selectivity of >99% is validated. The system is competent in dealing with saline NH 4 +-N wastewater with a wide range of NH 4 +-N (20∼200 mg N/L) and NaCl (6∼10 g/L) concentrations. In the treatment of realistic landfill leachate (884 mg N/L NH 4 +-N), C-BiOCl displays a photocatalytic NH 4 +-N removal efficiency of up to 95.6% while maintaining the NO 2 −-N (∼2 mg N/L) and NO 3 −-N (∼40 mg N/L) levels. This system provided an interesting and innovative idea for wastewater self-purification. [ABSTRACT FROM AUTHOR]

[Display omitted] • BiOCl/MXene composite was synthesized via a hydrothermal reaction. • The effect of MXene on the morphology of BiOCl was studied. • PDDA was used to adjust the electronegativity of the MXene surface. • PDDA modified BiOCl/MXene has high dichlorination ability and cycling stability. • Capacitive deionization (CDI) was simulated using COMSOL Multiphysics. Currently, chloride ions in industrial water limits its reuse when extending the circulating water cycle. Therefore, it is necessary to remove Cl− to ensure its effective reuse. Considering the development of new materials for efficient electrochemical chloride removal is a key issue limiting the development of capacitive deionization technology for chlorine removal. In this study, BiOCl was grown in situ on the surface of V-MXene, and then a nanoflower-like BiOCl/MXene composite was synthesized by utilizing the properties of MXene as a structure-directing agent to modulate the morphology, which exhibits superior pore structure and specific capacitance. The poly (diallyl dimethylammonium) (PDDA) modification improved the materials' specific capacitance and reduced energy consumption for dichlorination. The optimal BMP-10 exhibited superior performance for dichlorination, the maximum dichlorination capacity and rate were 161.64 mg g−1 and 2.20 mg g−1 min−1. We found that MXene has excellent properties for exfoliation and morphology modulation of layered materials. Additionally, the electrical properties have an important influence on the electrochemical removal of chloride ions. Here we successfully synthesized an efficient electrode material with unique morphological structure for CDI dichlorination and provided ideas for structure-directing agents and electrical modulation in material design for electrochemical dichlorination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydroxychavicol was isolated from the Piper betle − leaf water extract and firstly employed as a corrosion inhibitor. • Hydroxychavicol acted as a mixed-type inhibitor with a greater inclination towards anodic characteristics. • The capability to shield mild steel from carbon dioxide corrosion is due to the protective film formation. • Hydroxychavicol possibly inhibited localized corrosion due to random distribution of corrosion depth. Hydroxychavicol compound was isolated from Piper betle L. leaf and identified via preparative high performance liquid chromatography (Prep-HPLC) and nuclear magnetic resonance (NMR) spectroscopy. Hydroxychavicol compound was demonstrated to be a potential inhibitor for mild steel corrosion in carbon dioxide-containing environments due to the formation of a barrier layer on the steel surface. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) results indicated that the inclusion of hydroxychavicol in the aggressive environment made steel surfaces more homogeneous and smoother with a rough mean square roughness of 7.78 nm, whereas the steel surface was severely corroded in the blank solution. Moreover, X-ray photoelectron spectroscopy (XPS) results showed an enrichment of hydroxychavicol species combined with iron oxides and hydroxides on the mild steel surface. This can lead to the creation of a protective layer on the mild steel surface, thereby enhancing corrosion protection and localized inhibition. The work suggested a novel approach to isolate corrosion inhibitors from natural products, particularly agricultural by-products for mild steel in carbon dioxide and chloride ion environment with high inhibition performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sludge porous carbon created rough surface and exposed flake structure for mayenite. • The removal efficiencies of Cl− and SO 4 2− reached 68 % and 77 %, respectively. • A high Cl− adsorption capacity of 97 mg/g was achieved from FGD wastewater. • Mayenite has a negative Cl embedding energy and is favorable for the embedding of Cl. • The Cl− removal product possessed high degradation efficiency of carbonyl sulfide. The high concentration of chloride ions (Cl−) in flue gas desulfurization (FGD) wastewater not only corrodes equipment but also reduces the quality of desulfurization gypsum. The mayenite (Ca 12 Al 14 O 33) has a notable capacity for adsorbing Cl−, but its efficacy is hindered by its inherently low specific surface area and long reaction time. To improve the effectiveness of mayenite in Cl− removal, the porous carbon derived from sewage sludge (SSC) was employed to modify the mayenite-based Ca/Al oxides (CAO). The resultant SSC/CAO composites featured a predominant mayenite phase with rough surface and exposed flake structure, leading to an increase in surface area from 2 m2/g for CAO to 54 m2/g for SSC/CAO-1 (mass ratio of sewage sludge: CAO = 1: 1). Within 2 h of reaction, SSC/CAO-1 achieved a Cl− removal efficiency of 68 % and a high Cl− adsorption capacity of 97 mg/g. The Cl− removal mechanism is related to the presence of a higher percentage of AlO 4 5-, more oxygen vacancies, and larger surface area in SSC/CAO-1 compared to that in CAO, which facilitated the dissolution and reconstruction of the [Ca − Al − O] framework, resulting in the formation of Ca 2 Al(OH) 6 Cl·2H 2 O with high crystallinity. The negative Cl embedding energy indicates that Ca 12 Al 14 O 33 is favorable for the embedding of Cl, and its transformation into Ca 2 Al(OH) 6 Cl·2H 2 O occurs spontaneously. The final product after Cl− removal consisted of efficient components to obtain high catalytic hydrolysis efficiency of carbonyl sulfide, which holds great importance to address the issue of handling the Cl– removal product during backend treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • 15 %Ag 2 CO 3 /TiO 2 /SiC (ATS-15) photodegraded 95.87 % tetracycline (TC) in 30 min. • ATS-15 maintains high TC degradation rates among pH 3 to 9 and in natural water. • The generated AgCl combines with ATS-15 to enhance photoactivity. • Dual Z-scheme charge transfer and SiC surface oxidation enhance catalytic activity. The increasing issue of antibiotic contamination in water has sparked significant interest in seeking effective solutions. In this research, a dual Z-scheme ternary photocatalyst Ag 2 CO 3 /TiO 2 /SiC (ATS) was synthesized by a mechanochemical-coprecipitation method. The experimental results demonstrated that the 15 %Ag 2 CO 3 /TiO 2 /SiC (ATS-15) reached a remarkable tetracycline (TC) degradation efficiency of 95.87 % (k = 0.1063 min−1) after a 30 min exposure to visible light, which was 46.22 and 13.63 times more effective than SiC (k = 0.0023 min−1) and TiO 2 /SiC (k = 0.0078 min−1), respectively. The synergistic effect of ATS ternary structure to promote Si electron transfer and SiC surface oxidation. The photocatalytic performance of ATS-15 was greatly enhanced due to the synergistic effect of Cl− and CO 3 •−, achieving 95 % of TC degradation within 5 min. In the ATS-15 system, Cl− converts a portion of Ag 2 CO 3 into AgCl and establishes a quaternary electron transfer scheme with ATS-15, thereby enhancing the performance of the photocatalyst. ATS-15 photocatalyst can maintain TC degradation rate above 90 % among pH 3 to 9. The ATS-15 system also exhibits excellent adaptability to various water environment, achieving 94.01 % TC degradation rate in natural river water, with only a 1 % reduction. A novel treatment scheme for antibiotic pollution in a complex water environment was proposed by ATS-15 photocatalyst with high pH stability and water applicability. [ABSTRACT FROM AUTHOR]

[Display omitted] • A CNT-CeO 2 electrode is fabricated to selectively remove F− in mixed ion solutions. • CNTs increase the conductivity of the electrode and hinder the aggregation of CeO 2. • Pseudo-capacitance behavior of F– entering CeO 2 was observed first time by EQCM. • The energy consumption for treating actual groundwater using scaled-up equipment is low at approximately 0.2 kWh/m3. Selective capacitive deionization (SCDI) is a promising process for preferentially removing specific ions from waters with complex compositions. The selectivity towards certain species in CDI is most frequently achieved through novel electrode materials with high affinities towards targeted species. In this study, we investigate the selective removal of fluoride ions from groundwater containing concentrated co-existing chloride ions. A carbon nanotube-CeO 2 (CNT-CeO 2) electrode is employed for the electro-sorption of fluoride ions. Our findings are compelling: when processing a mixed F−/Cl− solution comprising 10 mg/L F− and 100 mg/L Cl−, the CNT-CeO 2 electrode is seen to reduce the concentration of F− ions to 1.5 mg/L in just 150 min, amounting to an 85 % F− removal efficiency, while the Cl− removal efficiency remains below 2 %. Importantly, this translates to a F−/Cl− separation factor of up to 4.16 when using the CeO 2 -based electrodes, which is 40 times higher than that achieved with conventional activated carbon (AC) electrodes. Furthermore, the energy consumption for treating actual groundwater using scaled-up equipment is impressively low at approximately 0.2 kWh/m3. The high affinity of CNT-CeO 2 towards fluoride is attributed to the intercalation Faraday capacitance initiated by the reaction between F− with CeO 2 , as verified by the electrochemical quartz crystal microbalance (EQCM). Moreover, EQCM results show a substantial increase in both mass and current as the potential increased beyond 0.8 V vs Ag/AgCl, implying that the current surge is not a result of water splitting but rather the adsorption of F− onto the CNT-CeO 2 electrode. The addition of CNTs substantially increases the conductivity of CeO 2 electrodes and restricts the aggregation of CeO 2 , thereby accelerating ion diffusion and promoting selective adsorption characteristics. Importantly, our electro-driven approach demonstrates excellent adsorption–desorption over 20 cycles. This comprehensive study advances the technological development of selective CDI, while providing new insights for fluoride removal in groundwater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Refractory ICMs were effectively removed through a novel oxidation pathway. • The oxidation is not related to traditional radicals, ROS, or high valent metals. • Inner-sphere surface-bound PDS abstracts electrons from the ICM probe directly. • Less degradation products were produced than that of traditional radical oxidation. Peroxydisulfate (PDS) is an appealing oxidant to eliminate water pollutants due to the relatively low cost and high stability compared with other peroxides. It needs to be activated for application, with non-radical producing processes being specifically preferred to obtain high selectivity and to reduce useless consumption of active species by ubiquitous chloride ions. Unfortunately, most of the current non-radical oxidation processes of PDS are ineffective toward inert pollutants. Here we report a novel non-radical PDS oxidation process initiated by CuO-MgO composites toward effective removing refractory iodinated contrast media compounds (ICMs). The optimized CuO-MgO composite was 18-times more efficient than CuO in activating PDS to remove iopamidol, a typical refractory ICM, and exhibited much lower Cu2+ leaching. Interestingly, the enhanced oxidation is not related to radicals, reactive oxygen species (ROS), or high valent Cu(III). We revealed with a series of surface characterization and density functional theory calculation that the CuO-MgO composite has Cu2+-Mg2+ heterojunctions of high electron density, thus is more active than CuO alone for PDS activation. PDS interacted with the composite surface in inner-sphere mode; consequently, the surface-bound PDS abstracted electrons directly from inert pollutants. Due to the lower oxidation power than traditional radicals, PDS/CuO-MgO oxidation of the ICM probe was insensitive to chloride and produced less hydroxyl- and nitro- degradation products. This research highlights that Cu2+-Mg2+ heterojunctions can play an important role in enhancing the non-radical and non-ROS oxidation capability of PDS toward inert pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Degradation of ultrashort- to long-chain PFAS with chain lengths C1-C13. • Application of a realistic individual PFAS content of 0.2 µg L−1. • Use of multi-solute systems with 24 C1-C13 PFAS and 8 C1-C8 PFAS. • Higher PFAS decay in real water matrices up to a given content of organics. • Need for current densities higher than 20 mA cm−2 to maximize the decay of most PFAS. The current study aimed to investigate major knowledge gaps regarding the application of the anodic oxidation (AO) process with boron-doped diamond (BDD) anodes for the remediation of water matrices contaminated with per- and polyfluoroalkyl substances (PFAS). This included: (i) the degradation of ultrashort-chain (C1-C3) and long-chain (C9-C13) PFAS in addition to short- and medium-chain (C4-C8) PFAS, (ii) the application of multi-solute systems with different PFAS content (0.2 µg L−1 versus 2.0 µg L−1) and diversity (24 C1-C13 versus 8 C1-C8) in addition to single-solute systems, (iii) the use of real water matrices in addition to pure water, and (iv) the application of current densities (j) up to 250 mA cm−2 in addition to usual j (≤20 mA cm−2). C1-C4 PFAS with a sulfonated headgroup were the most recalcitrant compounds. By contrast, PFAS ≥ C9 with a sulfonated headgroup and PFAS ≥ C12 with a carboxylic headgroup were potentially instantaneously degraded. The content and diversity of PFAS mainly affected the degradation kinetics of PFEtS (C2), PFPrA (C3), and PFBA (C4). Four real water matrices were under focus: drinking water (DW), urban wastewater after secondary treatment (UWW), and nanofiltration concentrate (NF) and reverse osmosis concentrate (RO) from urban wastewater polishing step. PFAS degradation typically benefited from using real matrices primarily due to the presence of chloride ions and consequent electrogeneration of active chlorine species. However, for waters with a high organic content, namely a chemical oxygen demand (COD) of 319 mg O 2 L−1, PFAS degradation was hindered. Furthermore, the removal of most PFAS benefited from the application of j > 20 mA cm−2, and some specific PFAS required the use of j ≥ 250 mA cm−2 to have maximized removal rates. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single-atom Fe catalysts with different coordination numbers were simply prepared. • Fe-N 3 /C/PMS system exhibits excellent degradation performance of TC. • The coordination numbers of single-atom Fe regulates the activation pathway of PMS. • The free radical/non-free radical co-oxidation has high reactivity and stability. • Electron transfer mechanisms between Fe-N x /C and PMS are proposed. In the reaction systems involving peroxymonosulfate (PMS) activation, the degradation of organic pollutants is influenced by the distinct roles played by the oxidation of free radicals and non-free radicals. The synergistic effect resulting from both oxidation pathways is often more efficient compared to a single oxidation pathway, as it allows for the optimal utilization of oxidation capacity and adaptation to complex reaction environments. Nitrogen-doped carbon substrates hosting single-atom catalysts (SACs) are anticipated to serve as an optimal platform for managing the dual oxidation pathways in the PMS activation reaction. This is attributed to the availability of numerous reaction sites that meet the activation requirements. However, there's a lack of substantial reports on this subject. Herein, we synthesized a series of single-atoms Fe nitrogen-doped carbon catalysts with different coordination structures by adjusting the coordination numbers between Fe and N atoms. It is used to investigate the reaction pattern of PMS over SACs, so as to enhance the catalytic efficacy of SACs through distinct coordination structures. The experimental and theoretical results indicate that PMS functions as both an electron receiver and provider on FeN x /C catalysts. Moreover, the specific arrangement of the Fe-N-C structure influences the exchange of electrons between the catalysts and PMS. Hence, the co-oxidation pathway of free radicals (OH, SO 4 − and O 2 −) and non-free radicals (1O 2) can be modulated by altering the coordination number of Fe and N atoms during PMS activation. The elimination efficiency of tetracycline hydrochloride was significantly enhanced due to the abundance of both free radical and non-free radical species generated in the FeN 3 /C/PMS reaction system, exhibiting a degradation kinetic constant of 0.564 min−1. In addition, it showed promising potential for application in practical wastewater degradation, exhibiting high anti-interference to general environmental disturbances (such as humic acid, chloride ions, bicarbonate ions and nitrate ions). [ABSTRACT FROM AUTHOR]

[Display omitted] • Bimetallic Rh x Cu/Ti on Ti mesh substrate was synthesized via step electroplating. • Morphology and metal ratio of Rh clusters influence the electrocatalyst reactivity. • Phase transition of Rh(II) ⇌ Rh(0) mediates electrons of ClO 4 −(ads) to ClO 3 (ads). • Hydrogenation on Cu sites synergistically improves the yield of chloride ions. • Electrodialysis facilitates anion migration towards Rh x Cu/Ti and energy efficiency. Perchlorate (ClO 4 −) contamination in the aquatic environments presents challenges for remediation due to its high solubility and chemical inertness. A bimetallic Rh x Cu/Ti was synthesized by incorporating rhodium (Rh) nanoclusters onto the copper crystallites on a titanium mesh substrate for electro-reduction of perchlorate ions. Characterization, which included voltammetry, Raman spectroscopy, and constant potential electrolysis, elucidated the reduction mechanism of perchlorate. A reversible phase transition of Rh(0) ⇌ Rh(II) was found to be an effective electron mediator of adsorbed ClO 4 −, where the neighboring Cu sites were responsible for hydrogenation of chlorinated intermediates. The dispersity of Rh clusters was influenced by the Rh-to-Cu ratio, thereby enhancing the electrochemical reactivity. The bimetallic electrode with around 30 % Rh coverage, i.e., Rh 0.3 Cu/Ti, possessed superior removal and faradaic efficiency within a potential range of −0.6 V to −0.8 V (vs. Ag/AgCl, at pH 3), which were 95 % and 78 %, respectively. The electro-reduction (ER) and the associated electrodialysis (ED) divided using ion exchange membrane were demonstrated for the treatment of perchlorate wastewater. The electrical field applied by the ED unit drove the migration of ClO 4 − ions to the surfaces of Rh 0.3 Cu/Ti cathode, further improving the removal efficiency of perchlorate and lowering energy consumption. [ABSTRACT FROM AUTHOR]

[Display omitted] • An Oxyfluoride (CoFeOF/NF) catalyst repelling Cl- ions is designed. • CoFeOF/NF anode suppresses Cl- ions in seawater thereby preventing the corrosion. • CoFeOF/NF shows outstanding stability for 145 h@400 mAcm−2 in seawater electrolysis. • This demonstrates a highly promising catalyst for freshwater and seawater electrolysis. Designing an inherently active and anti-corrosive catalyst to produce green hydrogen efficiently with a high stability is the key step in seawater splitting. Herein, a novel and highly active bifunctional electrode comprising CoFe-oxyfluorides (CoFeOF) nanosheets anchored on a nickel foam (NF) is designed via a simple hydrothermal route. The fabricated CoFeOF/NF electrode exhibits an exceptionally active and robust electrocatalysis in 1.0 M−based alkaline freshwater, artificial seawater, and natural seawater. In particular, the CoFeOF/NF electrodes drive the alkaline water electrolysis under 10 and 100 mAcm−2 at 236 and 280 mV (OER overpotential), 93 and 199 mV (HER overpotential) in freshwater; 230 mV and 290 mV (OER overpotential), 164 and 267 mV (HER overpotential) in artificial seawater; 220 and 280 mV (OER overpotential), 162 and 254 mV (HER overpotential) in natural seawater, respectively. More importantly, the two identical CoFeOF/NF || CoFeOF/NF electrode-based electrolyzer demonstrates a robust durability at a high current load of 400 mA.cm −2 for 145 h even in the natural seawater-based electrolyte. Based on this finding, it is anticipated that the highly electronegative oxygen and fluoride ions of the CoFeOF electrostatically suppress the highly corrosive chloride ions at the vicinity of the electrode, thereby inhibiting the corrosion of the CoFeOF/NF during the OER even at a high current load in seawater. This indicates the industrial potentiality of the CoFeOF/NF electrode in green-hydrogen generation sustainably via electrolysis of the abundantly available seawater. [ABSTRACT FROM AUTHOR]

[Display omitted] Mass production of Bi3+ and Te4+ co-doped vacancy-ordered Cs 2 HfCl 6 (CHC) double perovskites (DPs) under room temperature (RT) was reported, which was enabled by the rationally designed ligand of [Hmim]Cl. The resultant CHC DPs exhibit overall excellent performance with robust photostability and superior PL QY of 96.4%, ∼2 times to the highest one of the analogues obtained at RT ever reported. • The PLQY of CHC DPs can be optimized to 96.4% with the assistance of [Hmim]Cl. • The multi-functional effects of [Hmim]Cl ligand have been clarified. • The mass production of high-quality CHC DPs at room temperature has been achieved. Vacancy-ordered double perovskites (DPs) are promising candidates for modern white light-emitting-diodes (WLEDs) due to their low toxicity and unique optical properties. However, the grand challenge is that DPs synthesized at room temperature (RT) typically have a low photoluminescence quantum yield (PLQY), most of which reported below 51 %, making them impractical for applications. Here, we present a facile strategy for the mass production of Bi3+ and Te4+ co-doped Cs 2 HfCl 6 (CHC) DPs at RT, to realize single-component dual-band emission with a high color rendering index. It is witnessed that the rationally designed ligand [Hmim]Cl facilitates a strong chemical interaction between the ligand and DPs. This interaction allows [Hmim]Cl to coordinate with undercoordinated Hf4+ ions and provide excess chloride ions to the surface of the DPs. Consequently, it effectively controls the crystallization of DPs, protects them against moisture, reduces surface defects, and increases the migration barrier of halogen ions. As a result, the DPs exhibit excellent overall performance with robust photostability and a superior PLQY of 96.4 %, which is ∼ 2 times the highest reported value for similar DPs synthesized at RT. Current work presents a potential pathway for the mass production of high-quality DPs under mild conditions, leading to the development of signal-component WLEDs. [ABSTRACT FROM AUTHOR]

• Wide range of Cl- concentrations (1–500 mM) can effectively promote ATZ and SIM degradation. • The electron transfer at the interface was enhanced by the injection of Cl- in the Fe/Co@C/PMS system. • Two mechanisms of Cl· action in the system were proposed. • 1O 2 , ·OH, Cl· and S O 4 · - coexisted, and the role of Cl· in ATZ and SIM degradation cannot be ignored. In this work, a carbon-based catalyst Fe/Co@C with MOF as a self-sacrificing template was prepared by high-temperature roasting of FeCo-MIL101, which was applied to activate PMS for the degradation of chlorotriazine herbicides (ATZ and SIM) showing excellent performance. Characterization analysis revealed that Fe/Co@C possesses a certain graphene structure and has a saturation magnetization rate of 0.87 emu/g, which can be separated from the solution easily and quickly. The degradation of ATZ and SIM was enhanced by introducing chloride ions into the system, and 100 mmol/L Cl- could lead to the complete removal of ATZ and SIM in 6 min, while improving the interfacial electron transfer of Fe/Co@C/PMS. In combination with quenching experiments, ESR test results and DFT calculations, two important roles of chlorine radicals in the reaction are proposed: (1) direct electron transfer and (2) indirect promotion of 1O 2 generation through the production of HOCl. In addition, the testing of the influencing factors of the catalyst in the system (catalyst dosing, PMS dosing, pH, temperature), the testing of coexisting anions in the aqueous matrix, and the reusability all showed satisfactory performance. Finally, the degradation mechanisms of ATZ and SIM were proposed in combination with GC–MS determination of contaminant intermediates and analysis of their toxicity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The concentration of Cl− has a significant impact on the conversion of oxidative species. • The CoS@FeS catalyst can improve RhB mineralization and inhibition of the AOX formation. • The in-situ generation of H 2 O 2 consumes HClO and thus inhibits the formation of AOX. • The H 2 O 2 concentration related closely with the catalyst and O 2 dosages. The presence of chloride ions (Cl−) in dye wastewater can hinder the peroxymonosulfate (PMS) oxidation and lead to the abundant production of toxic adsorbable organic halogens (AOX). In this study, we investigate the detailed influence of Cl− on Rhodamine B (RhB) removal and its mechanism, and propose a potential pathway for 1O 2 -dominated systems to inhibit AOX formation. The concentration of Cl− has a dual effect on the degradation of RhB, with low concentrations inhibiting and high concentrations promoting. Further studies have revealed that Cl− significantly impact the generation and transformation of reactive oxygen species (ROSs). EPR capturing, quenching tests, and molecular probe experiments indicate that as the Cl− concentration increases, the concentration of SO 4 −, OH and their contribution to the degradation of RhB gradually decrease, 1O 2 slightly increase and then decrease, while HClO and chlorine radicals increase linearly. Additionally, the catalyst plays a crucial role in inhibiting AOX formation and improving the mineralization of RhB. On the one hand, introducing catalysts can alter the proportion of ROSs production. On the other hand, the in-situ generation of H 2 O 2 on the catalyst surface, through O 2 adsorption at sulfur vacancies sites, consumes the produced HClO, thereby inhibiting the formation of AOX. This study proposed a new insight into the mechanism for effective reduction of AOX content for 1O 2 dominated non-radical PMS activation under saline water. [ABSTRACT FROM AUTHOR]

• A novel bimetallic catalyst (Fe NC Co SA -C 3 N 4) for PMS activation was developed. • Fe NC Co SA -C 3 N 4 outperformed the counterpart homogenous catalysts for PMS activation. • Sulfate and hydroxyl radicals moderately contributed to paracetamol degradation. • Catalyst/PMS complex dominated the paracetamol degradation via electron transfer. Catalysts with metal nanocluster and single-atom sites have been used extensively to activate persulfate to remove recalcitrant pollutants while the bimetallic catalyst remains limited researches. Here, a bimetallic C 3 N 4 catalyst with relatively high Fe nanocluster and single-atom Co loadings (7.6% and 3.7%, respectively) (Fe NC Co SA -C 3 N 4) was successfully synthesized. Fe NC Co SA -C 3 N 4 showed a synergistic coefficient of 7.8 relative to Fe-C 3 N 4 and Co-C 3 N 4 for degrading paracetamol, remarkedly outperforming the counterpart monometallic heterogeneous catalysts, metal ions homogeneous catalyst, or previously reported catalysts in terms of peroxymonosulfate (PMS) activation and paracetamol mitigation. The Fe NC Co SA -C 3 N 4 /PMS complex contributed to > 60% of paracetamol degradation, whereas radical species and high-valent metal-oxo species contributed 13.3%–15.6% of paracetamol degradation. Fe NC Co SA -C 3 N 4 /PMS preferentially oxidizes organic pollutants containing electron-donating moieties but may be negatively affected by inorganic carbon and chloride ions. Synthesizing the bimetallic cluster/atom catalyst offers a new way of achieving efficient PMS activation and pollutant oxidation via catalyst/PMS complex formation and electron-transfer reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The competition adsorption mechanism of NH 3 and CB at low temperature is revealed. • Byproduct of NH 3 -SCO promotes deep oxidation of intermediates in CBCO reaction. • The forms of N and Cl species in simultaneous catalytic oxidation are unveiled. As the emission limits for NO x become further stringent, development of a synergistic control technology to prevent emissions of slipped ammonia (NH 3) and chlorinated organics from steel production and waste incineration is both a prospect and a challenge for the environmental issues. In this work, the designed ruthenium-based catalyst (RuNb/ST) showed the excellent chlorobenzene (CB)/NH 3 synergistic removal performance and N 2 /CO 2 selectivity above 300 ℃. The activity of NH 3 and CB were suppressed at relatively low temperature due to the competitive adsorption of CB and NH 3. Whereas, there was a significant improvement in the N 2 /CO 2 selectivity at relatively high temperature. The removal mechanism was studied by experiments, in which the accumulation of chlorine species, the role of NO 2 and the oxidation of CB were considerable. In contrast to the carrier, the vast majority of the chloride ions adsorbed onto the active sites after dissociating from CB could be efficiently removed in form of Cl 2 via the Deacon Reaction catalyzed by RuO 2. CB was predominantly converted into CO 2 and H 2 O with a fraction persisting as organics. Partial of organics were attacked by Cl ions to generate organic chlorine-containing by-products. The presence of NO 2 molecule was found to promote the cleavage of the benzene ring within CB, and expedited the carbon migration towards the ultimate product of CO 2 , resulting in a notable reduction of byproducts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Transformation pathway of phenol in the PMS/chloride system was pH-dependent. • PMS-Cl− interactions at acidic pH resulted in formation of reactive chlorine species. • Phenol underwent chlorination and mineralization at acid and alkaline pHs respective. • 1O 2 was responsible for the efficient phenol degradation at neutral to alkaline pHs. Abstract The formation of halogenated disinfection byproducts (DBPs) during organic pollutants degradation in advanced oxidation processes (AOPs) has raised growing concerns globally. However, the detailed roles of chlorine ions (Cl−) in pollutant degradation by peroxymonosulfate (PMS) alone remain controversial so far. Here, we shed light on the PMS-Cl−-phenol interactions and revealed a previously overlooked pH-dependent phenol transformation pathway. At acidic pH, Cl− significantly accelerated the phenol removal. The Cl−-PMS reaction resulted in abundant reactive chlorine species, which attacked phenol to form 4-chlorophenol and 2, 4-dichlorophenol as the main transformation products. In contrast, the impact of Cl− became negligible at alkaline pH. Raising the pH severely suppressed the phenol chlorination and significantly stimulated generation of singlet oxygen (1O 2) for degradation of phenol and the minor formed chlorophenols. The 1O 2 was resulted from a combined effect of PMS self-decomposition and PMS-benzoquinone interaction at alkaline pH. Our results imply a previously-underestimated impact of Cl− on phenolic compounds degradation in PMS-based AOPs and underscore a potential risk of chlorinated DBPs formation under environmental conditions. [ABSTRACT FROM AUTHOR]

Tritosulfuron has been eliminated by continuous addition of potassium peroxymonosulfate to an aqueous solution containing the herbicide and chloride ions. The influence of Cl − content (6·10 −5 –22.5·10 −4 M), inlet peroxymonosulfate concentration (0.05–0.2 M), initial tritosulfuron amount (0.5–2.5 mg L −1 ) and temperature (298–333 K) have been assessed. Tritosulfuron oxidation by HClO has been experimentally calculated to be in the proximity of 4.03 ± 0.15·10 13 exp(−7989/T) M −1 s −1 . Experimental data suggested the existence of an inefficient peroxymonosulfate decomposition, likely associated to the experimental setup used. A simple mechanism of first order ordinary differential equations is capable of acceptably simulate the profiles of tritosulfuron and peroxymonosulfate accumulated in the reactor, considering the formation of active chlorine species from the interaction of peroxymonosulfate and chloride. First oxidation intermediates have been identified by means of liquid chromatography coupled to high resolution mass spectrometry. The attack by hydroxyl radicals and the addition of chlorine have been appreciated in these generated species. An oxidation mechanism has also been proposed. The evolution of intermediates with reaction time indicates that few compounds are recalcitrant to the peroxymonosulfate/chloride system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cl− and Fe3+ significantly enhanced the Cu0 -stimulated PDS system for eliminating tetracycline. • Cl− and Fe3+ limited the dismutation of Cu+ and the oxidation of Cu+ by O 2. • SO 4 •−, •OH and RCS were generated in the in the Cl−/Fe3+/Cu0/PDS system. • Fe3+ and Cl− increased the utilization of copper in the Cl−/Fe3+/Cu0/PDS system. The Cu0-stimulated PDS system, which produces reactive oxygen species (ROS) to decompose environmental pollutants, has been widely studied. Although Cu+ is produced in the Cu0-stimulated PDS system, its susceptibility to disproportionate and easy oxidized by O 2 must be considered. To improve the utilization of Cu+, Cl− and Fe3+ were considered for strengthening the Cu0-stimulated PDS process. With the addition of Cl− and Fe3+ in the Cu0-stimulated PDS system (Cl−/Fe3+/Cu0/PDS system), the decomposition of tetracycline was greatly increased within 8 min. In the Cl−/Fe3+/Cu0/PDS system, Cl− limited the disproportionation reaction of Cu+ by promoting Cu0 and Cu2+ reaction with Cl− and increased Cu+ utilization rate. Fe3+ promoted the recycling of Fe2+/Fe3+ and contributed to reducing the invalid oxidation of Cu+ by O 2. Sulfate radical, reactive chlorine species and hydroxyl radical were generated in the Cl−/Fe3+/Cu0/PDS system. NO 3 − and SO 4 2− had no influence on decomposing tetracycline in the Cl−/Fe3+/Cu0/PDS system, but humic acid inhibited tetracycline decomposition. Moreover, the Cl−/Fe3+/Cu0/PDS system had great performance on the experimental water samples with the removal rate of tetracycline was higher than 80%. Furthermore, when the final solution pH was adjusted to 8.0, only 0.88 mg/L total dissolved copper remained after precipitation and filtering. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe3+ and Cl− significantly boosted Cu0/H 2 O 2 system for degrading acetaminophen. • The Fe3+/Cl−/Cu0/H 2 O 2 system generated reactive oxygen species, FeIVO2+, and •OH. • Fe3+ and Cl− weakened the oxidation of Cu+ and O 2 and the dismutation of Cu+. • Fe3+ and Cl− increased the utilization of Cu0 in the Fe3+/Cl−/Cu0/H 2 O 2 system. • The Fe3+/Cl−/Cu0/H 2 O 2 system greatly degraded acetaminophen in actual water. Zero-valent copper-triggered hydrogen peroxide (Cu0/H 2 O 2) process was widely used for the degradation of pollutants, while its oxidation efficacy was restrained by the interaction of Cu+ with O 2 as well as the dismutation of Cu+. In this study, both ferric ion (Fe3+) and chloride ion (Cl−) were introduced into the Cu0/H 2 O 2 (Fe3+/Cl−/Cu0/H 2 O 2) system, and the removal of acetaminophen was immensely enhanced. In the Fe3+/Cl−/Cu0/H 2 O 2 , Fe3+ was converted to Fe2+ via the reaction of Fe3+ with Cu0 and Cu+, and the reaction between Cu+ and Fe3+ receded the reaction of Cu+ with O 2 , promoting the formation of reactive oxygen species; Cl− integrated with Cu+ to form the Cu-Cl chelate, and Cl− helped the comproportionation of Cu0 and Cu2+ to form CuCl, which decreased the reaction of Cu+ with O 2 and promoted the generation of reactive oxygen species. Both the addition of Fe3+ and Cl− in the Cu0/H 2 O 2 process greatly improved the utilization of Cu0. •OH, Various reactive oxygen species such as •OH, FeIVO2+ and reactive chlorine species were identified in the Fe3+/Cl−/Cu0/H 2 O 2 process. There into, Fe2+ stimulated H 2 O 2 to form •OH and FeIVO2+, and Cu+ triggered H 2 O 2 to form •OH rather than Cu3+, and partial •OH was transferred to reactive chlorine species via the interaction of •OH with Cl−. After increasing the solution pH to > 7.0 and leaching solution, the total copper of reaction solution was below 0.455 mg/L. These results suggested that the Fe3+/Cl−/Cu0/H 2 O 2 process was feasible, effective and environmentally safe, and the research offered a theory instruction for the application of Fe3+ and Cl−-enhanced Cu0/H 2 O 2 process in pollutants decomposition. [ABSTRACT FROM AUTHOR]

We propose an UV/chlorine advanced oxidation process using chlorine production by the anodic oxidation of chloride ions (UV/electro-chlorine process). The UV/electro-chlorine process developed steadily degraded 1,4-dioxane. The advanced oxidation performance of the UV/electro-chlorine process without pH control deteriorated with an increase in the initial pH. An increase in pH observed during the UV/electro-chlorine process was due to the accumulation of free chlorine. As the pH increased from the initial pH of 4.1 or higher, the solution pH exceeded the pKa of hypochlorous acid (HOCl), which decreased the advanced oxidation performance and enhanced the formation of chlorine-centered oxyanions of chlorite and chlorate (ClO x − ). To maintain a pH lower than the pKa of HOCl, a reagent-free pH control system, involving switching on and off the electrochemical chlorine production at a threshold of pH 6.1, was introduced into the UV/electro-chlorine process. When the UV/electro-chlorine process with pH control was operated at the initial pH of 4.3 or higher, the 1,4-dioxane degradation rate was inhibited by the shortage of free chlorine production. However, the degradation rate at an initial pH of 4.2 or lower was enhanced because of a higher percentage of HOCl to free chlorine and a higher contribution of Cl 2 − to 1,4-dioxane degradation. The energy consumption rate of 1,4-dioxane removal and the molar ratio to ClO x − formation were improved by the pH control at the same initial pH range. [ABSTRACT FROM AUTHOR]

The effect of operating parameters on the extraction and separation of La and Ce, from chloride solution containing one complexing agent lactic acid, using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (EHEHPA, P507) as an extractant, has been studied. Results show that extraction efficiencies increase as pH and residence time increase, while decrease with the increasing of channel width and mixture velocity. A better separation effect is obtained using microfluidic extraction at optimal conditions. The extraction rates (0.1214 s −1 for La and 0.3231 s −1 for Ce) determined in microfluidic extraction, are much larger than those (0.0058 s −1 for La and 0.0068 s −1 for Ce) in conventional solvent extractors, which are largely attributed to the higher surface-to-volume ratio achieved in microfluidic experiments. The overall mass transfer coefficients ( K L a ) increase with increase in mixture velocity, while decrease with increase in channel size including channel width and length. The significant difference in K L a of Ce (0.05–0.162 s −1 ) as compared to La (0.004–0.129 s −1 ) imply better separation effect. Compared with conventional extractors such as mixer-settler and centrifugal extractor, microfluidic extraction has much higher mass transfer rates. [ABSTRACT FROM AUTHOR]

[Display omitted] • MCC was functionalized via milling and subsequent oxidation for HMF synthesis. • The pretreatment reduced degree of polymerization/crystallinity & increased acidity. • The formed –COOH played role in both pretreatment & reaction media, promoted by Cl−. • Up to 55% HMF yield was obtained from the functionalized MCC without catalyst. Selective cellulose transformation into the 5-hydroxymethylfurfural (HMF), a versatile platform chemical, has been researched using various catalysts, while desirable efficiency remains a challenge. This study revealed an alternative conversion approach to strong acidic/basic catalysis, an efficient one-pot synthesis of HMF without external catalyst from microcrystalline cellulose (MCC), functionalized via milling and subsequent oxidation pretreatment. The outstanding HMF yield (∼55%) was obtained under moderate reaction conditions (3 h, 190 °C), demonstrating the significant impact of functionalized MCC's characteristics (e.g., reduced crystallinity index (CI), degree of polymerization (DP), and the formed –COOH) and the reaction conditions (e.g., the role of NaCl and H 2 O/THF ratio) for HMF synthesis. The formed –COOH group demonstrated a dual-function i) in-situ destruction of MCC's β -1,4-glycosidic linkages during pretreatment ii) catalyzing hydrolysis/dehydration reactions of carbohydrates to form HMF. Furthermore, chloride ions could selectively promote consecutive reactions. The promising findings in this study provide a greener route to produce HMF from cellulose without using acid/base catalysts through cellulose structure functionalization by green/simple methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • Perylene diimide/peroxymonosulfate/visible light (PDI/PMS/Vis) system showed excellent performance for iohexol removal. • 0.56% of chloride ions (Cl−) absorbed on the surface of hydrochloric acid-induced self-assembled PDI (P C). • The Cl− adsorbed on the surface of P C improved the electrostatic potential distribution and promoted the charge transfer. • Holes, singlet oxygen, and superoxide radical were the dominant active species for iohexol elimination. The presence of iohexol (IOX) in the environment has attracted widespread attention. Acetic acid, hydrochloric acid, and nitric acid tailored self-assembled perylene diimides (P A , P C and P N) were prepared and utilized in different visible-light-driven activation of peroxymonosulfate (PMS/Vis) systems for the degradation of IOX. As an electron acceptor, PMS can significantly hinder the recombination of photogenerated electron-hole pairs. The removal rate of 5 mg/L IOX by P C /PMS/Vis system reached 99.1% at 30 min, which was 2.0 times and 1.3 times higher than that of P A /PMS/Vis and P N /PMS/Vis system. The boosted oxidation activity with P C was due to the pH dependence of perylene diimide (PDI) self-assembly and the small amount of Cl− (0.56%) absorbed on P C , which can promote the transfer of electron-hole pairs, change the surface charge distribution and energy band position, and enhance π-electron conjugation. Based on density functional theory and electrostatic potential calculation, the Cl− adsorbed on the surface of PDI brings an effect on the electrostatic potential distribution. Furthermore, the built-in intermolecular electric field leads to accelerated charge transfer of PDI. In the P C /PMS/Vis system, holes, singlet oxygen and superoxide radical were perceived as the dominant contributors. The degradation of IOX carried out via pathways of amide hydrolysis, amino oxidation, hydrogen abstraction, deiodination reaction, and OH attack. This work provides a new method for the pollution control of IOX and scientific guidance for the tailored self-assembly of organic supramolecules. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sucralose can be completely degraded by the enriched consortia within 4 days. • Five biotransformation products were detected and a degradation pathway was proposed. • The enrichments were characterized by combining Illumina and Nanopore technologies. • The function of sucralose biodegradation was driven by novel species. Sucralose has been regarded as an emerging pollutant with growing concerns owing to its environmental persistence and potential risks to ecosystems and human health. However, limited information is currently available regarding its biodegradability and degradation pathway in the environment. In this study, complete and efficient sucralose biodegradation was achieved by enriched consortia seeded with activated sludge. In the enrichments with sucralose as the sole carbon source, 73 % of the total organic carbon was removed with a maximum degradation rate of 3.87 mg sucralose/g VSS·h−1, coupling with the release of three chloride ions of sucralose. Additionally, five biotransformation products, namely TP-409N, TP-373N, TP-357N, TP-455N, and TP-393N, were determined by UPLC-QTOF-MS, and an aerobic sucralose-degrading pathway was proposed. Then, Illumina and Nanopore sequencing were employed to provide a genome-centric resolution of microbial communities, demonstrating that the enriched consortia were dominated by Proteobacteria , Bacteroidota , Chloroflexota , and Planctomycetota. At the species level, over half of metagenome-assembled genomes were potentially affiliated with new lineages, implying that the function of sucralose biodegradation was driven by some novel species (at the genus level). Combined with the network analysis, species from UBA11579 and Polyangiaceae were suspected to be involved in the biodegradation of sucralose. This research evidenced the bacterial biodegradability of sucralose and first demonstrated the sucralose-biodegrading pathway and microbial communities, providing novel insights into sucralose biodegradation in the environment. [ABSTRACT FROM AUTHOR]

The efficiency and, accordingly, the success of the advanced oxidation processes (AOPs) has generally been evaluated on the basis of degradation kinetics. In practice, chloride in saline wastewater is often found to inhibit degradation processes. Therefore its highly desirable to develop more effective processes which are not affected by chloride. In this study, no significant interference of chloride with monochlorophenols (MCPs, e.g. 2-CP, 3-CP and 4-CP) degradation by the UV photo-activated persulfate (UV/PS) process has been observed. This indicated the “illusion” that the UV/PS process might have been an appropriate technology working under saline conditions. To further evaluate its applicability, the generation of reaction intermediates, of adsorbable organic halogen (AOX) accumulation and of acute toxicity of MCPs in the UV/PS system were examined. In reality, several aromatic chlorinated compounds (number of chlorine atoms ≥2), such as dichlorophenols and 2,3,5,3′,5′-pentachloro-biphenyl, were identified and quantified. An accumulation and relative increase of AOX with reaction time was observed in the UV/PS/Cl system. The acute toxicity tests with Photobacterium phosphoreum indicated that the inhibition effect of UV/PS reactions increased with reaction time regardless of the presence of chloride or not. The results of this study might be helpful for assessing the PS-based technologies for saline wastewater treatment. [ABSTRACT FROM AUTHOR]

The use of untreated seawater or bore water in uranium mineral processing circuits may represent a cheaper and more sustainable water resource for Australia’s mining operations. Using present technologies, the increased salinity from these water sources results in decreased uranium extraction and increased extraction of impurities. There is incentive to overcome these challenges, either through new technologies, or repurposing existing technologies. The ion exchange behaviour of U from sulfate media on the weakly basic chelating resin Dowex M4195 (bis-picolylamine functionality) and the effect of competing chloride and impurity metal ions (Th, Fe, Al, Cu, Ni) has been studied. Experiments to determine acid, and sulfate media behaviour, and extraction thermodynamics including the effect of increasing chloride concentration upon extraction behaviour were carried out. Dowex M4195 was found to have pK 1 and pK 2 values at 4.13 ± 0.04 and 2.1 ± 0.1 determined at 1.0 M NaCl. Dowex M4195 shows affinity for U(VI) over Fe 3+ and Al 3+ in sulfuric acid media with a U(VI) pH 50 a full pH unit below that of Fe 3+ at 0.17 and 1.82 respectively. With increasing chloride concentrations U and Th extraction is suppressed but Fe extraction increases. At the highest chloride concentrations explored Fe is preferentially extracted over U, and Th is not extracted at all. As chloride concentration increases the extraction of U passes through a minimum (40%) before increasing to around 60% for 4.0 M chloride at pH 1.80. Al 3+ is not extracted by M4195 under any conditions explored. Dowex M4195 does show high selectivity for Cu and Ni over everything else. [ABSTRACT FROM AUTHOR]

Computational high-throughput screening of MII 3 MIII/IV layered double hydroxide (LDH) (MII = Ni and Co; MIII/IV = Ni, Co, Fe, V, Cr and Ti) for chloride ion batteries (CIBs) is carried out by using density functional theory plus U (DFT + U) method. The "bridging function" of H atoms and the unique Cl H O MIII/IV "atomic electron transfer chain" structure between LDHs slabs and inserted-Cl in the chlorination reaction were revealed for the first time. [Display omitted] • Computational high-throughput screening is performed among 12 cases of LDHs. • H atoms "bridging" and Cl H O MIII/IV atomic chain are revealed for the first time. • Ti-containing LDHs are screened as promising cathodes, which has never been reported. • Ni 3 Ti-Cl LDH is synthesized experimentally and exhibits a predicted high performance. The chloride-ion battery (CIB) based on the anion transfer plays an essential role in developing new battery technologies. As a rare anion intercalated layered material, layered double hydroxide (LDHs) has attracted considerable attention as promising cathodes for CIBs. However, driven by the great compositional diversity, developing a general methodology to effective design and assess the usability of unexploited LDHs for CIBs is still a challenging issue. Herein, a computational high-throughput screening is performed among MII 3 MIII/IV LDHs (MII = Ni and Co; MIII/IV = Ni, Co, Fe, V, Cr and Ti). When designated as the only guest in LDHs gallery, Cl atoms tend to absorb above the O atoms without MIII/IV around and adsorption energy increases with the order of Ti > Cr > V > Fe > Co > undoped hydroxides. During the chlorination reaction, a special Cl H O MIII/IV electron transfer chain is proposed for the first time. Furthermore, Cl storage performance for 11 cathodes were evacuated by the theoretical voltage in a full CIB system. The results indicates Ti-containing LDHs is the most encouraging cathodes, which is verified by the experimental measurement. This work provides a clear guidance and a theoretical insight into the anion insertion electrochemistry for LDHs materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A considerable productivity and selectivity of methanol (180.75 μmol·g cat −1·h−1, 80.07 %) are achieved. • Cl− could be transformed into Cl over BiOCl-O v to efficiently activate methane. • The in situ produced Cl is constrained on the surface of BiOCl-O v , inhibiting over halogenation. • Reactive oxygen species produced by H 2 O 2 dissociation are utilized to be the receptors of CH 3. Selective partial oxidation of methane to methanol under mild conditions remains a great challenge in activating the first C H bond of CH 4 and inhibiting overoxidation. Chlorine-mediated pathway arises as a promising strategy to obtain high CH 4 conversion under mild conditions. Herein, a considerable CH 3 OH production rate of 180.75 μmol·g cat −1·h−1 with 80.07 % selectivity is achieved when the BiOCl with oxygen vacancies is irradiated by visible light in NaCl solution with H 2 O 2 addition. Experimental studies reveal that chlorine radicals are in situ produced and constrained on the surface of the catalyst, which inhibits the over halogenation. Reactive oxygen species produced by H 2 O 2 dissociation were utilized to be the receptors of CH 3. The high productivity of methanol was achieved by the synergy effect of chlorine radicals and H 2 O 2. This work provides a new feasible method to convert inert methane into high-value-added products via photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enhanced degradation of OCs was obtained by TAP in the presence of Cl−. • Different reactive species contributed to OCs degradation during Cl−/TAP oxidation. • TOC removal efficiencies were 52.6 %–69.0 % using TAP in the existence of Cl−. • The concentrations of typical CBPs were 17.2 μg/L–86.3 μg/L in Cl−/TAP system. The effect of chloride ion (Cl−) on the degradation of organic contaminants (OCs) by thermally activated peroxymonosulfate (TAP) was assessed in this study. P -aminobenzoic acid (PABA), sulfadiazine (SDZ), bisphenol A (BPA), and chloramphenicol (CAP) were employed as model OCs with different structure. The degradation efficiencies of PABA, SDZ, BPA, and CAP were respectively 76.4 %, 90.8 %, 10.1 %, and 14.5 % by TAP (70 °C) after 60 min treatment, further raised to 97.6 %, 97.4 %, 55.2 %, and 30.5 % in the presence of Cl− (1 mM). When Cl− concentration increased to 10 mM, PABA and SDZ were completely degraded respectively after 7 min and 10 min, 97.1 % of BPA and 59.5 % of CAP were removed within 60 min. In TAP system, PABA and SDZ were primarily degraded by direct peroxymonosulfate (PMS) oxidation, while BPA and CAP were mostly removed by hydroxyl radical and sulfate radical oxidation. In Cl−/TAP mixtures, the degradation of PABA and BPA was mainly attributed to hypochlorous acid oxidation, SDZ was chiefly removed via direct PMS oxidation, and CAP was principally oxidized by radicals. Furthermore, the intermediate products of OCs degradation during Cl−/TAP oxidation were identified, and primary degradation pathways were proposed. The removal efficiencies of total organic carbon were markedly improved from 19.3 % to 25.3 % by TAP to 52.6 %–69.0 % in Cl/TAP system. The concentrations of typical chlorinated by-products after OCs oxidation were 17.2 μg/L–86.3 μg/L in Cl−/TAP system. Considering the complexity of actual wastewater, 51.3 %–100 % removal efficiencies of OCs by TAP oxidation were achieved in Cl−-containing secondary effluent. Understanding the role of Cl− in OCs degradation is essential for the practical application of Cl−/TAP oxidation in advanced wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cl− significantly boosted Cu0 system for degrading acetaminophen. • Cl− promoted the generation of H 2 O 2 in the Cu0 system. • Cl− reduced the dismutation of Cu+ via forming Cu-Cl complexes. • Cl− was conducive to the comproportionation reaction of Cu2+ and Cu0. • Acetaminophen in actual water samples was greatly degraded by Cl−/Cu0 system. Zero-valent copper particles (Cu0) used to degrade pollutant due to its in-site generation and activation of hydrogen peroxide (H 2 O 2), while the disproportionation of Cu+ limited the efficacy. In this study, spiking chloride ion (Cl−) into zero-valent copper (Cu0) system (Cl−/Cu0 system) enhanced greatly acetaminophen degradation. The addition of Cl− not only reduced the dismutation reaction of Cu+, but also helped the comproportionation reaction of Cu0 and Cu2+, leading to much generation of Cu+ and H 2 O 2. Hydroxyl radical (OH) and reactive chlorine species were identified as the dominant reactive oxidants in the Cl−/Cu0 system with its contribution ratio of degrading acetaminophen being respectively 73.4 % and 23.8 %. In the Cl−/Cu0 system, Cu+ was released by H+ corrosion from Cu0, and then Cu+ coupled with Cl− forming Cu-Cl complexes; Meanwhile, the reaction of O 2 and the species of Cu+ (e. g. Cu-Cl complexes and Cu+) produced H 2 O 2 and, then the species of Cu+ catalyzed H 2 O 2 to form OH; Thereinto, partial OH was shifted by Cl− to reactive chlorine species. Except for fulvic acid, coexisting substrates such as sulphate, nitrate and phosphate ions had no obvious inhibition impact on oxidizing acetaminophen in the Cl−/Cu0 system. Furthermore, the Cl−/Cu0 system presented a good removal rate of acetaminophen in three actual water samples. Moreover, three kinds of dyes and painkillers was removed over 78 % in the Cl−/Cu0 system. The residual total dissolved copper was under II-level of environmental quality standards for surface water in China by alkali precipitation and filtration after reaction. Therefore, the study provided a new idea to enhance Cu0 for the purification of pollutants. [ABSTRACT FROM AUTHOR]

• A novel strategy to construct a triple functional filler was developed. • The synthesis of Bt@PDA@LM cleverly borrowed the method of fabricating LDH films on metal substrates. • The coating integrated barrier properties, chloride ion trapping effect and self-healing function. • The coating exhibited long-term anti-corrosion performance. The long-term anti-corrosion performance of ordinary coatings is unsatisfactory due to their poor barrier properties. Herein, we developed a strategy to construct a triple functional filler by first modifying basalt scales (Bt) with polydopamine (PDA) to introduce active sites, followed by in situ growth of molybdate-loaded layered double hydroxide (LM) on the surface of PDA-modified basalt. This novel strategy not only avoided stacking between LDHs, but also improved the interfacial compatibility between fillers and epoxy resin, which endowed the anti-corrosion system with intelligent self-healing function and barrier anti-corrosion characteristic. Tafel curves obtained in solution phase proved that compared with carbon steel immersed in pure 3.5 wt% NaCl solution, the introduction of Bt@PDA@LM causes the I corr to decrease from 1.18 × 10-5 A/cm2 to 2.05 × 10-6 A/cm2 and the corrosion inhibition efficiency reaches 82.63%. Combined with the significant enhancement of the low-frequency impedance of the scratched Bt@PDA@LM/EP coating during immersion in 3.5 wt% NaCl solution, the effective corrosion inhibition of the designed filler was demonstrated. Moreover, the low-frequency impedance of the Bt@PDA@LM/EP coating is about 660 times higher than that of the pure epoxy (EP) coating after immersion in 3.5 wt% NaCl solution for 120 days and is still as high as 4.96 × 1010 ohm·cm2 after 200 days of immersion. The excellent corrosion resistance can be attributed to the synergistic effect of barrier property, chloride ion trapping effect and corrosion inhibition of the obtained filler. Thence, it is believed that this research will provide insights in developing new long-term anti-corrosion coatings and break the application limitations of polymer-based coatings to some extent. [ABSTRACT FROM AUTHOR]

The effect of the chloride ions (Cl − ) on the efficiency of Fe 0 /sand systems for methylene blue (MB) discoloration was characterized in column studies for 4 months. Tested systems were: pure sand (0% Fe 0 – reference) and Fe 0 /sand (50% Fe 0 – vol/vol). Tested Cl − concentrations were 0.0, 2.1, 21.1 and 42.2 mM. The used MB concentration was 16 μM (5 mg L −1 ) and used Fe 0 mass was 100 g. Discoloration experiments lasted for 89 days and was followed by a 26 days desorption experiment. Each system was characterized by the time-dependent changes of the pH value, the iron breakthrough, the MB breakthrough, and the hydraulic conductivity (permeability). During the discoloration experiments, a total of 17.4 L (184 pore volumes) of the MB solution flowed through each column (279.0 μM dye or 87.2 mg). No significance changes in pH value and permeability could be documented. Discoloration and desorption results confirmed that sand is an excellent MB adsorbent (only 11% desorption in the reference system). In the absence of Cl − , 15 mg MB was discolored. Up to 18 mg of MB was discolored in the presence of Cl − . The same trend was observed in changes of the extent of iron release which was 7.3 mg at 0.0 mM Cl − and 16.2 mg at 42.2 mM Cl − . These results confirm that chloride ions enhance the kinetics of Fe 0 corrosion and thus the production of contaminant collectors (for MB co-precipitation). Results confirmed the suitability of MB as a powerful operative indicator for the characterization of processes in the Fe 0 /H 2 O system. [ABSTRACT FROM AUTHOR]

Calcium peroxide (CP) combined persulfate (PS) oxidation is an emerging in situ chemical oxidation (ISCO) technology for ground water remediation. Many field cases also confirm its effectiveness in ground water remediation while few research articles document it. This study investigated the performance of α-methylnaphthalene (MN) degradation by PS/CP to further understand this dual oxidant application in ISCO. Results showed that MN could be completely oxidized in 72 h with 1 g L −1 PS and 1 g L −1 CP. The degradation rates of MN increased with the increase of PS and CP concentration. MN degradation was significantly enhanced with the solution pH decrease, because CP was easier to dissolve and generated more radicals in acidic condition. Solutes in ground water including chloride ions, alkalinity and natural organic matters presented inhibitory effect on MN degradation in this dual oxidant system. Plausible mechanisms of the sulfate and hydroxyl radicals in the system were proposed based on the results of radical scavenging experiments and electron spin resonance (ESR) tests. It appeared that surface OH of CP was also responsible for the MN removal. The major oxidation products in this study were 1-naphthaldehdye, naphthalene-1-ylmethanol and 4-hydroxy-4-methylnaphthalen-1(4H)-one. To better understand PS/CP in ISCO, the degradation of MN was tested in ground water matrix, which showed satisfactory efficiency. The results of this study provided some detail information of PS/CP dual oxidant in degradation organic contaminants, which might provide some references for the application of this technology in ISCO. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fluid–solid-chemical coupled fractal model is developed. • The fractal dimension of tortuosity decreases rapidly with corrosion. • The corrosion of low porosity concrete reinforced by chloride ions can improve the transport of chloride ions. • The change of concrete porosity has nonlinear effect on steel corrosion and concrete pore structure evolution. Chloride ion invasion into reinforced concrete is a common disease. In this study, we combine the diffusion of free chloride ions, the corrosive expansion of iron, and the destruction of concrete. Considering the fractal characteristics of concrete pore structure, a fractal diffusivity model is established. A fluid–solid-chemical coupling model was established considering the non-uniform corrosion of iron. The correctness of the model is verified by comparison with experimental data. The corrosion thickness and pore structure evolution of concrete under different chloride ion concentration invasion and different porosity were simulated. The results show that: (1) the fractal dimension of tortuosity decreases gradually and then sharply at the initial stage of corrosion; (2) compared with concrete with high porosity, concrete with low porosity invaded by chloride ions has a more significant improvement in its own transport; (3) concrete porosity has nonlinear effect on steel corrosion and concrete pore structure evolution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trihalophenols were effectively degraded and dehalogenated by PDS/BC system. • Various water matrices have different influence on trihalophenols degradation. • Degradation pathway involved dehalogenation and hydroxylation. • PDS/BC treatment greatly eliminated the toxicity of trihalophenols. In this study, highly efficient dehalogenation and detoxification of trihalophenols was achieved by activated peroxydisulfate (PDS) with black carbon (BC) derived from coal tar. 93.8% of 2,4,6-tricholophenol (TCP), 97.6% of 2,4,6-tribromophenol (TBrP) and almost 100% of 2,4,6-triiodophenol (TIP) was respectively oxidized by PDS (500 μM) in the presence of 20 mg/L of BC. 1O 2 and surface-bound radicals were proved to be dominant oxidizing species responsible for trihalophenols degradation. Alkaline condition was favorable for PDS/BC oxidation process to degrade trihalophenols. Chloride ion and natural organic matter (NOM) would suppress the oxidation of trihalophenols, while bicarbonate ion presented a promoting effect. Meanwhile, Cl‾, Br‾ and IO 3 ‾ was formed during the degradation of TCP, TBrP and TIP, respectively, with approximately 43.5% of TCP, 52.4% of TBrP and 61.8% of TIP dehalogenated. No detection of toxic byproduct ClO 3 ‾ and BrO 3 ‾ was observed in the PDS/BC system owing to the excellent reducing capacity of BC to rapidly convert reactive halogen intermediates (HOX) to X‾. Products analyses showed that trihalophenols were oxidatively transformed to dehalogenated-hydroxylated products by the PDS/BC system and these halogenated intermediates could be further degraded. Moreover, the toxicity of trihalophenols was confirmed to be effectively eliminated by the PDS/BC system through In-vitro toxicity assay based on luminescent bacteria test and in-silico toxicity prediction through ECOSAR program. Therefore, PDS/BC oxidation technology is a promising strategy for removing trihalophenols and their toxic by-products in treated water effluent. [ABSTRACT FROM AUTHOR]

• CoFe-LDH/MXene membrane was used as the Cl- storage electrode in CDI; • The electron transport of the CoFe-LDH layer was improved by MXene; • CoFe-LDH/MXene membrane has enough toughness to be self-supporting; • The desalination capacity of the membrane reached 149.25 ± 6.17 mg g−1. Excessive chloride ions (Cl-) are undesirable in water. However, most of the research on the application of capacitive deionization in desalination has focused on cation storage electrode materials, whereas less on the equally important Cl- storage electrode materials. Herein, the CoFe-Layered Double Hydroxide (CoFe-LDH) prepared by chemical co-precipitation was composited with MXene through simple vacuum filtration to form a self-supporting CoFe-LDH/Ti 3 C 2 T x film electrode, and used as the anode material to store Cl- in the hybrid capacitive deionization system. The CoFe-LDH/Ti 3 C 2 T x composite film has a hierarchical micro-mesoporous architecture, larger electrochemical capacity, and desalination capacity, reaching 149.25 ± 6.17 mg g−1 at a current density of 50 mA g−1 and desalination rate of 3.86 mg g−1 min−1 at 100 mA g−1. This work provides potential inspiration for the Cl- storage electrode for capacitive deionization technology. [ABSTRACT FROM AUTHOR]

• Non-hydrolytic synthesis of SnO 2 NCs using t -BuOH improved Cl passivation and dispersibility. • t -SnO 2 effectively passivated defects at the interface between perovskite layer and ETL. • t -SnO 2 ETL-based regular (n-i-p) PSCs achieved a PCE of 20.2% and excellent device stability, maintaining 97% of initial PCE after 70 days. • t -SnO 2 has also been successfully applied as ETL to inverted (p-i-n) PSCs and inverted (n-i-p) OSCs. Recently, tin oxide (SnO 2) has attracted great attention as a promising electron transport layer (ETL) material for perovskite solar cells (PSCs) due to its high electron mobility, low-temperature fabrication and superior photocatalytic stability. However, there remains room for further utilization of the full potential of this material and improvement in power conversion efficiency (PCE) of devices, including establishment of controllable synthetic process and efficient surface modification. In this study, we first report on the novel tert -butyl alcohol (t -BuOH)-mediated non-hydrolytic synthesis of SnO 2 nanocrystals (NCs) with effective pre-Cl-passivation without additional treatment. In this reaction, the by-products, tert -butyl chloride and water, are readily hydrolyzed to t -BuOH and chloride ions, which can be continuously reused and boost the reaction. Consequently, Cl effectively passivates the surface of SnO 2 NCs as well as facilitates the dispersion stability, leading to reduced trap density and enhanced charge extraction characteristics of the SnO 2 ETL. The device fabricated using the t -BuOH-mediated SnO 2 NCs exhibits improved device efficiency, excellent reproducibility, reduced hysteresis, and longer device stability compared to the device using SnO 2 NCs synthesized by conventional non-hydrolytic process. For the regular type (n-i-p) PSCs, the device achieves a PCE of 20.2% and maintains 97% of initial efficiency after 70 days under ambient conditions. In addition, unnecessary high temperature annealing and additional treatment of the non-hydrolytically synthesized SnO 2 NCs enable their direct deposition on the perovskite layer, thereby leading to inverted type (p-i-n) PSCs with the best PCE of 17.0%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chloride pre-intercalated CoFe-layered double hydroxide (CoFeCl-LDH) was prepared. • CoFeCl-LDH was used as Cl--capturing electrode for rocking-chair CDI system. • The system exhibits an ultrahigh desalination capacity and fast desalination rate. Faradic electrochemical deionization (EDI), as the next generation of capacitive deionization (CDI), was considered one of the most promising solutions to address the global fresh-water shortage, while rationalizing its cell architecture and developing suitable electrode material are of equal importance to the desalination performance of EDI. In this work, chloride pre-intercalated CoFe-layered double hydroxides (LDH) (CoFeCl-LDHs) were fabricated through coprecipitation and further used as Cl- capturing electrodes for rocking-chair CDI (RCDI) system. By coupling the advantages of both rational cell architecture (symmetric RCDI system with balanced ion storage) and suitable electrode material (reversible Cl- intercalation and fast charge transfer), the CoFeCl-LDH-based RCDI system exhibits an ultrahigh desalination capacity (100.2 mg g−1) and fast desalination rate (0.38 mg g−1 s−1), which outpperform those of the other LDH-based CDI systems. The outstanding desalination performance of the CoFeCl-LDH-based RCDI further demonstrates the critical importance of both electrode material and cell architecture to the EDI system, which could shed light on the future design of highly efficient EDI systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • NaOH showed dramatical enhancement for ACE elimination in heat/PMS system. • 1O 2 and •OH were the primary reactive oxygen species responsible for ACE degradation. • 1O 2 and •OH separately came from base-activated PMS and thermolysis of peroxide bond. • Chloride ion significantly accelerated ACE removal in NaOH-enhanced heat/PMS system. • Heat/PMS system had better performance than heat/PDS system under alkaline conditions. Owing to the high peroxide bond dissociation energy (377 kJ mol−1), peroxymonosulfate (PMS) is rather difficult to be activated by heat for degrading organic pollutants. This work is the first to add sodium hydroxide (NaOH) to enhance the elimination of acetaminophen in heat/PMS system. Heat/PMS system even possessed a better Performance than heat/peroxydisulfate (PDS) system with the addition of NaOH. Quenching experiments and electron paramagnetic resonance tests demonstrated that singlet oxygen and hydroxyl radical were the primary reactive oxygen species responsible for acetaminophen elimination in NaOH-enhanced heat/PMS system. Singlet oxygen mainly came from the alkaline activation of PMS, while hydroxyl radical was generated from the thermolysis of peroxide bond. Increasing PMS concentration and reaction temperature favored the production of reactive oxygen species and the elimination of acetaminophen. Nine degradation intermediates of acetaminophen were identified by LC/TOF/MS and the corresponding degradation pathways were proposed. Chloride ion significantly accelerated the elimination of acetaminophen, while humic acid and carbonate ion slightly retarded acetaminophen removal. NaOH-enhanced heat/PMS system was highly efficient in eliminating many organic pollutants and more prone to degrading electron-rich organics. This study developed a simple and efficient approach to strengthening the oxidation capacity of heat-activated PMS and highlighted the superiority of PMS to PDS in thermolysis under alkaline conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalyst activated PMS oxidation process was used for the degradation of model NAs. • PMS catalyst B-FeO x was synthetized and employed for model NAs degradation. • Relative kinetics of model NAs in B-FeO x /PMS oxidation system were studied. • The reaction between SO 4 •− and OH– generated •OH (responsible for model NAs degradation). • The presence of chlorine ions suppressed the degradation rate of model NAs. Naphthenic acids (NAs) are a mixture of aliphatic and alicyclic carboxylic acids which are persistent in the environment. In this study, a sludge-based biochar/iron oxide (B-FeO x) catalyst with 3D flower-like shaped structure was prepared through a facile hydrothermal method. For the first time, the B-FeO x catalyst was employed to activate peroxymonosulfate (PMS) for the removal of two model NA compounds (1-adamantanecarboxylic acid (ACA) and 4-methylheptanoic acid) at pH 8.50. Compared to biochar or FeO x alone, a higher degradation efficiency (96.1%) and faster degradation rate (k = 0.100 min−1) of ACA were obtained by the B-FeO x composite at a catalyst dose of 2.0 g/L and PMS dose of 2.5 mM. The higher degradation efficiency of B-FeO x was attributed to the improved surface area and pore volume as well as the abundant reactive sites induced by the flower-like structure. Furthermore, the hydroxyl radical (•OH) generated in the B-FeO x /PMS system was the dominant radical for both ACA and 4-methylheptanoic acid degradation as demonstrated through radical quenching experiments. The presence of chloride ions in the B-FeO x /PMS system showed a suppression effect on the degradation of ACA and 4-methylheptanoic acid at Cl− concentrations between 5 and 20 mM. No significant difference in the degradation rates of ACA and 4-methylheptanoic acid was observed at different Cl− concentrations. Overall, the results of this study showed that the sludge (waste material)-based B-FeO x composite may have the potential to be utilized as PMS catalyst for the removal of NAs that are especially abundant in oil sands process water. [ABSTRACT FROM AUTHOR]

[Display omitted] • CLQ as an antiviral drug might be persistent pollutant in surface water. • CLQ oxidation by Fe(VI) fitted second-order kinetics. • The degradation of CLQ by Fe(VI) was highly dependent on pH. • Aromatic ring dealkylation and chloride ion substitution are the main pathway. • CLQ oxidation by Fe(VI) slightly increased antimicrobial effect towards E. coli. Chloroquine (CLQ) is required to manufacture on a larger scale to combat COVID-19. The wastewater containing CLQ will be discharged into the natural water, which was resistant to environmental degradation. Herein, the degradation of CLQ by ferrate (Fe(VI)) was investigated, and the biodegradability of the oxidation products was examined to evaluate the potential application in natural water treatment. The reaction between CLQ and Fe(VI) was pH-dependent and followed second-order kinetics. The species-specific rate constant of protonated Fe(VI) species (HFeO 4 −) was higher than that of the FeO 4 2− species. Moreover, increasing the reaction temperature could increase the degradation rate of CLQ. Besides, HCO 3 − had positive effect on CLQ removal, while HA had negative effect on CLQ removal. But the experiments shows Fe(VI) could be used as an efficient technique to degrade co-existing CLQ in natural waters. During the oxidation, Fe(VI) attack could lead to aromatic ring dealkylation and chloride ion substitution to form seven intermediate products by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) determination. Finally, a pure culture test showed that the oxidation of CLQ by Fe(VI) could slightly increase the antimicrobial effect towards Escherichia coli (E.coli) and reduce the toxicity risk of intermediates. These findings might provide helpful information for the environmental elimination of CLQ. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amorphous clusters could act as mass transfer barrier for solutes. • CO 2 molecules can replace methylene blue residing in the cage. • Chloride ions can participate in cage building during the exclusion process. Hydration-based techniques involve hydrate formation in complicated systems containing ions and organics. Consequently, it is necessary to understand the molecular behavior of hydrate nucleation and growth in such solutions. This work shows that the hydrate-growth rate in a system containing methylene blue molecules does not necessarily accelerate on increasing the subcooling. Unexpected amorphous cage clusters were observed at a lower temperature of 240 K. To the best of our knowledge, this is the first study to propose that these amorphous clusters act as mass transfer barriers disturbing the agglomeration of solutes. Herein, hydrate growth was accompanied with the exclusion of methylene blue molecules. Although methylene blue can instantaneously reside in the cavity a half-cage structure, they were subsequently replaced by CO 2 molecules. Notably, chloride ions were observed to participate in cage building (42510, 512, and 51262 cages) by bonding with the oxygen atoms of the surrounding water molecules. This phenomenon shows an interaction between the methylene blue molecules and hydrate cages during the exclusion process. These results support the current understanding on hydrate formation in the presence of ion-containing organics and could help improve kinetics-dependent applications in separation process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Freezing significantly accumulates Oxone, Cl−, and H+ in the liquid brine. • Production of HOCl in the presence of Oxone and Cl− is enhanced by freezing. • Various organic compounds were degraded in the freezing/Oxone/Cl− system. • The freezing/Oxone/Cl− system worked efficiently under various conditions. • Outdoor freezing experiments confirmed a successful performance without electricity. Accelerated chemical reactions in frozen solutions can be applied in the degradation of organic pollutants in water. Herein we propose a novel freezing system that enables the degradation of various organic compounds in a frozen solution. Although the degradation of 4-chlorophenol (4-CP) by Oxone as the sole primary oxidant did not take place in aqueous solutions (25 °C) regardless of the presence of chloride ions (Cl−, micromolar levels) and only took place to a minor extent in frozen solutions (−20 °C) in the absence of Cl−, the addition of Cl− (micromolar levels) to the freezing/Oxone system significantly accelerated the degradation of 4-CP. Various analytical characterizations and pH measurements of the frozen solution suggested that the enhanced degradation of 4-CP in the freezing/Oxone/Cl− system could be because Cl−, Oxone, and protons are concentrated in the liquid brine upon freezing. This process subsequently facilitates the formation of hypochlorous acid (HOCl) as a secondary oxidant. The positive effect of Cl− was observed under widely varying conditions (i.e., [Cl−] = 25–1000 μM, pH i = 3–11, and freezing temperature = from −10 to −30 °C), and the freezing/Oxone/Cl− system described herein successfully degraded all 12 tested organic pollutants. In addition, outdoor freezing experiments carried out on winter days confirmed the successful performance of the freezing/Oxone/Cl− system without the requirement for electrical energy. [ABSTRACT FROM AUTHOR]

The detailed electrically switched ion exchange (ESIX) process for extraction/release of Cl- in the BiOCl/PPy-Cl hybrid film system is as follows. Firstly, applying a negative potential to the BiOCl/PPy-Cl hybrid film, BiOCl and the positively charged PPy are electrochemically reduced. As a result, Cl- doped in PPy as well as located between the [Bi 2 O 2 ] slabs can be quickly released into the regeneration solution by electrostatic repulsion. And then, specific Cl- vacancies and broader storage space are formed in the PPy-Cl shell and between the nanosheets layers, respectively. On the contrary, when the applied potential is converted to oxidation state, Cl- can be pushed into the hybrid film to keep the electrical neutrality. Consequently, the reversible uptake/release of Cl- can be realized by facilely manipulating the redox states of the hybrid film in the ESIX process. A schematic to illustrate the ESIX process of BiOCl/PPy-Cl hybrid film for electrochemically selective extraction of chloride ions. [Display omitted] • An electroactive hybrid film with core–shell nanosheet structure was fabricated. • Rapid uptake/release of Cl- was achieved by the collaboratively-driven force. • The superior selectivity was mainly attributed to the screening effect of PPy-Cl shell. • The Cl- adsorption capacity reached as high as 80.81 mg⋅g−1. The development of selective separation materials with large capacity and high selectivity has always been a research hotspot in the field of water remediation. In this study, an electroactive ion exchange hybrid film of bismuth oxychloride/chloride ion-imprinted polypyrrole (BiOCl/PPy-Cl) with core–shell nanosheet structure was successfully fabricated by a chemical oxidation method for selective extraction of chloride ions. Herein, the BiOCl/PPy-Cl hybrid film possessed superior conductivity due to the incorporation of the conductive polymer. Furthermore, the hybrid film could more quickly and effectively extract Cl- compared with BiOCl and PPy-Cl, and its uptake capacity reached as high as 80.81 mg⋅g−1 at the optimal potential of 0.6 V. Meanwhile, based on the screening effect brought by the outer PPy-Cl shell, the hybrid film displayed prominent selectivity toward Cl- even in the presence of other competing species. In addition, the hybrid film maintained steady adsorption capacity in 10 cycles as well as under different acid-base environments. The outstanding Cl- uptake performance of the hybrid film was primarily ascribed to the open interlayer structure of BiOCl and the collaboratively-driven force generated by the reversible electrochemical redox of BiOCl and PPy. It is expected that the obtained BiOCl/PPy-Cl hybrid film could be a promising alternative for the extraction of Cl- from wastewater. [ABSTRACT FROM AUTHOR]

From left to right: TES anchored on SiO 2 , Ag0 nanoparticle (TEM), calomel-amalgam coexistence (XRD) and Ag 1.1 Hg 0.9 nanoparticle (TEM) [Display omitted] • Biosourced silica functionalized with triethoxysilane and silver nanoparticles. • Rapid Hg2+ removal from high concentration chloride-containing aqueous solutions. • Competitive capacity levels achieved (21–101 mg/g). • Co-existence of calomel and amalgam on silica observed for first time. • Evidence of hyperstoichiometric interaction with Hg:Ag molar ratio higher than 3. This study presents the production of pure silica from rice husk and its stepwise functionalization with triethoxysilane (TES) and silver nanoparticles. The derived TES-SiO 2 (0.97 mmol TES per g of SiO 2) and Ag0@SiO 2 (3.70–21.60 mg Ag per g of SiO 2) materials were used for the removal of Hg2+ from aqueous solutions in the presence of chloride ions. The removal of Hg2+ was rapid and the equilibrium solid phase loading was between 21 and 101 mg/g. TES-SiO 2 was more effective than Ag0@SiO 2 in removing mercury due to the highly reactive hydride groups. In the case of Ag0@SiO 2 samples the removal of Hg2+ is proportional to the amount of Ag0. The materials were characterized before and after the removal of Hg2+ to allow insights into the interaction mechanism. The reaction products for TES-SiO 2 sample were calomel (Hg 2 Cl 2) and AgCl. On the surface of Ag0@SiO 2 samples besides these products the silver amalgams Ag 1.1 Hg 0.9 and possibly Ag 2 Hg 3 were identified. These results show that redox reactions between silicon-hydride group, Ag0 and Hg2+ take place on the surface of the materials. The coexistence of calomel and silver amalgams on amorphous silica is observed for the first time while the calomel formation in heterogeneous Hg2+ redox systems is a rare observation. Also, the samples showed extraordinary efficiency in terms of Hg:Ag molar ratio (2.28–3.02), considerably higher than those reported before. Besides the beneficial effect of the Cl- presence on the removal of Hg2+ from the solution there is evidence of a hyperstoichiometric interaction between Ag0 and Hg2+ at the nanoscale. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel catalyst Fe-MOF-74@SiO2@MIP was synthesized to activate persulfate. • Both selectivity and catalytic degradation performance of DMP was highly improved. • Operating factors, such as catalyst loading, persulfate concentration, solution pH and temperature, affect DMP degradation. • Chloride ion showed dual effects on DMP degradation through the generation of Cl-related radicals. • Radical coupling and hydroxylation reactions were mainly occurred during DMP degradation. In this work, persulfate (PS) activation by a novel functioned metal-organic framework catalyst was investigated for the targeted degradation of DMP, a toxic phthalate pollutant. The catalyst, a molecularly imprinted water-stable Fe-MOF-74 (Fe-MOF-74@SiO 2 @MIP), showed excellent capability of PS activation, high selectivity and efficient targeted degradation performance of DMP. The results of total organic carbon indicated that DMP was mineralized during the catalysis. EPR measurement and quenching experiments suggested the coexistence of SO 4 •− and •OH, and SO 4 •− was predominant in this system. It was found that increasing catalyst loading (0.01 - 0.05 g L-1) inhibited the DMP elimination, due to the aggravated radical consumption. A higher pseudo-first order rate of DMP degradation was observed with an increasement of PS (5.2 - 52 mM) and temperature (15 - 45 °C). Besides, coexisting chloride ions (Cl−) promoted the DMP degradation at the concentration 1 mM, but decreased the degradation performance at other concentrations. According to EPR and XPS analysis, the effect of Cl− was ascribed to the formation chlorine radicals, which changed the radical distribution and the catalytic site property. Chlorinated intermediates were detected by LC-MS, confirming the involvement of Cl-related radicals. Finally, possible degradation pathways were proposed. [ABSTRACT FROM AUTHOR]

The near-infrared (NIR) glass–ceramic (GC) photocatalysts directly collecting from the terminal Cl−-related precipitates after Cl− removal process are defined as defect-rich heterostructure (GC/BiOCl), which have excellent upconversion luminous energy transfer (LET) and electronic energy transmission (EET) properties, contributing to lower carriers recombination rate and better photocatalytic activity during the further norfloxacin degradation process upon NIR irradiation. [Display omitted] • Bi-contained glass–ceramic is developed to remove Cl− and removal rates exceed 96%. • The amount of H+ determines the Cl− removal efficiency. • The norfloxacin degradation rate under near-infrared irradiation reaches 36%. • The terminal Cl−-related precipitate is a defect-rich heterojunction photocatalyst. • The degradation pathways of norfloxacin under different wavelengths are distinctive. Concentrated leachate (CL) contains typical high concentration of Cl−, and it is necessary to remove Cl− efficiently and even to achieve a high value-added product from the Cl− removal process. In this study, a Bi-contained upconversion glass–ceramic (GC) is firstly explored for ultra-efficient removal and utilization of Cl−, wherein the abundant porous structure is continuously formed in the Cl− removal process to further provide channels for the deep migration of Cl− and H+ to its inner Bi source. The high Cl− removal rates above 96% were all achieved over the best GC sample at the Cl− concentrations of 1300–13,000 mg/L, then the terminal BiOCl-based precipitates were directly collected as the near-infrared (NIR) GC photocatalysts, which possessed defect-rich heterostructure with excellent upconversion luminescence and electronic energy transmission properties. In the degradation of norfloxacin (NOR), high removal rates of 98%, 73%, and 36% were achieved under UV–Vis-NIR, Vis-NIR, and NIR irradiations. On a basis of the four possible NOR degradation pathways discussed, we found that the primary active species were attributed to O 2 ·− and ·OH radicals under NIR and UV–Vis-NIR irradiations, respectively. Therefore, the Bi-contained GC will supply a new strategy for high-efficiency Cl− removal and value-added resource utilization. [ABSTRACT FROM AUTHOR]

• A chloride-resistance composite coating is fabricated by PDDA, EGCG and Heparin. • PDDA (inhibiting Cl-) and EGCG (chelating Mg2+) have synergistic anti-corrosion. • The coatings dramatically improve hemocompatibility and histocompatibility of AZ31 stent. • The coatings selectively promote endothelialization and inhibit intimal hyperplasia. Controlled corrosion and proper biological response are key demands for biodegradable Mg-alloy based vascular stents. To achieve those properties, herein, a chemical conversion coating was fabricated through layer-by-layer (LBL) assembly via the sequential assembly of poly (dimethyl-diallyl ammonium chloride) (PDDA), epigallocatechin gallate (EGCG) and heparin (Hep). Each component in the coating played a unique role, in which EGCG chelates Mg ions and enhances the stability of the coating by introducing multiple intermolecular interactions, while PDDA effectively enhances the resistance against chloride corrosion, and Hep provides adequate hemocompatibility and promotes endothelialization. Electrochemical assay and immersion test demonstrated that the synergistic combination of PDDA and EGCG effectively suppressed the corrosion rate. A systematic in vitro and ex-vivo evaluation demonstrated an impressive antithrombotic performance, along with a selective promotion of endothelial cells (ECs) proliferation and inhibition of smooth muscle cells (SMCs) growth and macrophages (MAs) activation. More importantly, subcutaneous implantation and implantation in the abdominal aorta wall indicated that the PDDA/EGCG/Hep-modified implants displayed good corrosion resistance and mild tissue response, enhanced endothelialization and suppressed intima hyperplasia. These promising outcomes revealed the clinical potential of the PDDA/EGCG/Hep coating on AZ31 as biodegradable cardiovascular implants. [ABSTRACT FROM AUTHOR]