Anodic oxidation presents a compelling strategy for pesticide-contained wastewater treatment. However, due to the reactive chlorine species-induced side reactions, toxic chlorinated byproducts are prevalent. Herein, a MOF derivative Ru-single-atom electrode, Ru-SbOX, was specialized for use in electro-pulsation to realize pesticide degradation and in-situ byproduct elimination. The introduction of single-atomic Ru promoted pseudocapacitive Run+-Sbn+ redox conversion, electro-creating metastable high-valent Sb5+ and low-valent Sb3+, then triggering the •OH and •H generation during anodic and cathodic cycles, respectively. This beneficially created an alternating oxidation-reduction environment in an identical electrode, leading to alternate pesticide degradation-byproduct elimination. These allowed Ru-SbOX to achieve a super-prominent normalized phoxim degradation kinetics constant (3.1 × 10-6 m·s-1) in anodic cycles, surpassing other state-of-the-art electrodes; meanwhile, the reactive chlorine species-induced chlorinated byproducts and even N, S, P-related byproducts were in-situ eliminated by at least 10 times in cathodic cycles. This work provides a new perspective for tuning the valence-variable metal in the single-atom electrode to achieve efficient pesticide degradation and in-situ byproduct elimination using the electro-pulsation method.

Membrane-based electrodeposition (MED) has emerged as a promising approach for reversible removal-recovery of toxic but valuable Pb2+. However, limited by the low specificity of membrane deposition toward various heavy metal ions in MED, the selective removal of Pb2+ remains an obstacle. Inspired by the soft-hard acid-base theory, here we developed a Pb2+-affinity electroactive membrane by incorporating MoS2 with the cation exchange membrane (CEM) to achieve a tandem Pb2+ selective adsorption-deposition process. CEM@MoS2 achieved nearly 100 % Pb2+ removal selectivity even in the presence of diverse competing cations, with a remarkable distribution coefficient (1.3 x 107 mL center dot g-1) and treatment capacity (2580.4 mg center dot g-1), resulting in a high-purity Pb2+ concentrate recovery. Importantly, a spontaneous Mo4+-Pb2+ redox reaction was found, which triggered Pb2+ reduction to metallic Pb. This surficial Pb degrees formation decreased the energy barrier for subsequent membrane H2O splitting and Pb2+ reduction, accounting for the unexpected self-enhanced Pb2+ removal scenario. Additionally, the exhausted Mo4+ species was facilely regenerated via a cathodic reduction method, demonstrating excellent stability and reusability. The work is expected to provide a viable strategy for selective removal-recovery of heavy metal ions using MED.

Redirecting the pathways of pollutant removal from mineralization to polymerization in advanced oxidation processes is critical for simultaneously achieving low‐carbon contamination abatement and chemical energy recovery, yet the regulating strategy remains an obstacle. Herein, single‐atom catalysts are constructed through an inherent oxide anchoring strategy for directionally inducing the polymerization removal of bisphenol A (BPA). An appropriate amount of Ru single atoms (Ru‐SA) on Ti 4 O 7 support is conducive to the formation of high‐valent metal species (Ru(IV)), with its corresponding steady‐state concentration three orders of magnitude higher than that of Ti 4 O 7 , while excessive Ru‐SA inevitably leads to mutual quenching of Ru(IV) due to the significantly reduced interatomic distances. Ru(IV) beneficially induced the generation of phenoxyl‐like radicals through electron transfer, thereby triggering BPA removal via electro‐polymerization transfer. As a result, Ru 0.1 ‐Ti 4 O 7 achieves higher activity with the normalized K obs of 8.33 × 10 −7 m·s −1 , the current efficiency of 63%, and the energy consumption of 37.5 kWh·kg −1 for the electro‐polymerization removal of BPA, outperforming the conventional mineralization strategy. This work presents an adaptive paradigm to regulate the inter‐distance of single‐atom catalysts to promote the generation of high‐valent metal species and optimize pollutant removal from wastewater via polymerization.

Electrochemically active materials can effectively alleviate mass transfer restriction by adding them as flowanodes into the electrochemical reactor. However, conventional flow-anode materials display a low center dot OH yield. Here, a novel flow-anode, CeOx/carbon black (CB), demonstrates superior electrocatalytic degradation efficiency of organic pollutants. The acetaminophen degradation kinetic constant of CeOx/CB was calculated to be 2.3-2.9 times higher than that of CB. CeOx/CB achieved a higher current efficiency of 66.4 % and relatively lower energy consumption of 157.8 kWh/kg COD compared with other GAC or gamma-Al2O3-based flow-anodes. The mechanistic analyses demonstrated that rapid electron transfer, strong water adsorption, and low reaction energy barrier of CeOx/CB actuated efficient center dot OH generation. Moreover, Ce(IV)/Ce(III) redox cycle crucially acted as an "electron porter" to accelerate the electron transfer from adsorbed H2O molecules to CB substrate directionally in the electro-oxidation process. This work provides a feasible manner for the development of flow-anodes utilizing the advantage of the Ce(IV)/Ce(III) redox cycle.

Membrane-based electro-deposition (MED) is an original process promising for reversible removal and recovery of toxic heavy metal ions from wastewater. The removal efficiency of heavy metal ions, however, was limited by the poor membrane surface H2O splitting in the conventional ion exchange membrane (IEM). Inspired by the amphoteric interface-triggered ion exchange resin regeneration phenomenon in electro-deionization, herein we subtly introduced the amphoteric group into IEM as a proof of concept to solve the above bottleneck. By virtue of the "electronic porter" role of the amphoteric- 3 OS-R-N(CH 3 ) 3 + , the electron extraction from adsorbed H2O could be accelerated, extending the H2O splitting from the conventional membrane surface to the bulk membrane interior. Such an H2O splitting extension favorably produced an intensified and well-modeled OH- production region at the anodic side of IEM, enhancing the Ni2+ basic deposition accordingly. This special characteristic allowed our MED to realize a super-eminent metal ion removal rate (10.5 mol center dot h- 1 center dot m- 2 ) along with an ultra-low specific energy consumption (0.1 kWh center dot mol-1) for Ni2+ removal, which considerably surpassed those of state-ofthe-art heavy metal ion removal processes reported yet. Further, the deposited Ni2+ could be in situ recovered in conjunction with the facile polarity reversal method. The amphoteric electroactive membrane with high H2O splitting activity is expected to pave the path to engineering MED for efficient heavy metal ion removal and recovery.

Electrochemical precipitation (EP) is recognized as a promising technology for its facile removal of metal ions via electrochemically-driven precipitation or reduction reactions. This article summarizes a comprehensive overview of its current advances. Three types of EP, i.e., cathodic EP, membrane-separated seed system, and membrane-based EP, are presented, with particular interest focusing on their principles, kernel components, scale detachment methods, reactor configurations, and industrial applications for water softening and heavy metal ion removal/recovery. In addition, the remaining challenges and perspectives in the future EP development are described.

Exploiting electrochemically active materials as flow-anodes can effectively alleviate mass transfer restriction in an electro-oxidation system. However, the electrocatalytic activity and persistence of the conventional flow-anode materials are insufficient, resulting in limited improvement in the electro-oxidation rate and efficiency. Herein, we reported a rational strategy to substantially enhance the electrocatalytic performance of flow-anodes in electro-oxidation by introducing the redox cycle of high-valent metal in a suitable carbon substrate. The characterization suggested that the SnOx-CeOx/carbon black (CB) featured well-distributed morphology, rapid charge transfer, high oxygen evolution potential, and strong water adsorption, and stood out among three kinds of SnOx-CeOx loaded carbon materials. Mechanistic analysis indicated that the redox cycle of Ce species played a key role in accelerating the electron transfer from SnOx to CB directionally and could continuously create the electron-deficient state of the SnOx, thereby sustainably triggering the generation of ·OH. All these features enabled the resulting SnOx-CeOx/CB flow-anode to accomplish a calculated maximum kinetic constant of 0.02461 1/min, a higher current efficiency of 47.1%, and a lower energy consumption of 21.3 kWh/kg COD compared with other conventional flow-anodes reported to date. Additionally, SnOx-CeOx/CB exhibited excellent stability with extremely low leaching concentrations of Sn and Ce ions. This study provides a feasible manner for efficient water decontamination using the electro-oxidation system with SnOx-CeOx/CB.

南方一些偏远山区由于海拔高、距离远,城镇供水管网难以延伸到位,而单村供水站主要存在浊度难以稳定达标、自用水率高的问题.为此,研发了一种半封闭气-水反冲洗接触絮凝过滤技术以处理农村饮用水,考察了其过滤性能与节水效果,并在浙江省永康市舟山镇舟一村进行应用示范.实验研究结果表明,在原水浊度为20 NTU、PAC投加量为1.5 mg/L、滤速为8 m/h、水温为25℃的条件下过滤28 h,平均出水浊度在0.2 NTU以下;在气冲强度为17 L/(m2.s)、水冲强度为4 L/(m2.s)的条件下进行气-水反冲洗,自用水率为0.96％,较单水反冲洗节约耗水67.2％.实际应用结果表明,运行3个月共计91个周期,平均出水浊度在0.5 NTU以下,过滤器最高允许液位达4～5m,自用水率为1.37％.

Under the environmental sustainability concept, landfill leachate concentrate can be up-cycled as a useful resource. Practical strategy for effective management of landfill leachate concentrate is to recover the existing humate as fertilizer purpose for plant growth. Herein, we designed an electro-neutral nanofiltration membrane to separate the humate and inorganic salts for achieving a sufficient humate recovery from leachate concentrate. The electro-neutral nanofiltration membrane yielded a high retention of humate (96.54 %) with an extremely low salt rejection (3.47 %), tremendously outperforming the state-of-the-art nanofiltration membranes and exhibiting superior promise in fractionation of humate and inorganic salts. With implementation of the pressure-driven concentration process, the electro-neutral nanofiltration membrane enriched the humate from 1756 to 51,466 mg∙L-1 at a fold of 32.6, enabling 90.0 % humate recovery and 96.4 % desalination efficiency from landfill leachate concentrate. Furthermore, the recovered humate not only exerted no phytotoxicity, but also significantly promoted the metabolism of red bean plants, serving as an effective green fertilizer. The study provides a conceptual and technical platform using high-performance electro-neutral nanofiltration membranes to extract the humate as a promising nutrient for fertilizer application, in view of sustainable landfill leachate concentrate treatment.

Electrocoagulation represents a promising process for hardness removal from cooling water. Nevertheless, the slow hydrolysis reaction severely restricted the floc formation, inhibiting the hardness co-precipitation and simultaneously causing secondary pollution from dissolved Al3+. Inspired by the detrimental membrane fouling phenomenon in conventional electrodialysis, we reported a rational strategy to substantially enhance the hardness removal efficiency in electrocoagulation by introducing a special membrane polarization-catalyzed H2O dissociation herein. Leveraging the electron transfer between functional groups (-SO3- and -N(CH3)3+) of ion exchange membrane (IEM) and surface-adsorbed H2O under the electric field-induced ion depletion scenario, H2O dissociation could be effectively catalyzed, with this catalytic activity more intensive in -SO3- than in -N(CH3)3+. Such a special H2O dissociation beneficially created a widely distributed and well-simulated alkalinity zone around the anodic region of IEM, which promoted the conversion of dissolved Al3+ to floc Al, thereby enhancing floc formation and circumventing secondary pollution. All these features enabled the resulting membrane-enhanced electrocoagulation (MEEC) to achieve a super-prominent hardness removal rate of 318.9 g h-1 m-2 with an ultra-low specific energy consumption of 3.8 kWh kg-1 CaCO3, considerably outperforming those of other conventional hardness removal processes reported to date. Additionally, in conjunction with a facile air-scoured washing method, MEEC exhibited excellent stability and universal applicability in various reaction conditions.

Membrane-based electrochemical precipitation (MEP) has been pioneered and demonstrated effective for hardness ion removal in cooling water, however, the removal of other ions was quite poor. To overcome such a problem, in this study, we presented a novel process, denoted membrane deposition electrodialysis (MDED), which incorporated MEP with electrodialysis (ED), for cooling water treatment. Desalination results demonstrated that MDED exhibited good ion step removal performance with a resultant high concentration selectivity of 4.2, which was attributed to the synergistic effect between membrane deposition and electro-migration, realizing zero-emission. The gradual scale formation caused by membrane deposition induced membrane property variation and then treatment performance deterioration, but delightedly, by using a distinct bi-pair electrode switching, the scale adhered to the membrane could be detached efficiently with a scale recovery reaching 96 %, bringing about subsequent membrane regeneration. More importantly, the bi-pair electrode switching displayed a super stable nature in the 1800 h accelerated life experiment, substantially eliminating the electrode stability decay problem that occurred in conventional polarity reversal. All these features allowed MDED to achieve satisfactory removal rate being about 5.8-15.9 M/h/m(2), which was 1.5-26.5 folds those of conventional processes, and it could work stably for at least 3 years under normal conditions, with almost no performance decay.

在电化学处理高硬度氨氮废水过程中,Ca2+、Mg2+等会在电场作用下富集并沉积在电极表面,引起电极结垢,最终影响氨氮去除效率.倒极除垢操作简单、脱垢效果佳,但会折损电极寿命.为了解决这一问题,研制了一种可在倒极操作下保持长寿命的Ti/RuO2-IrO2-RhOx新型电极,以用于处理上述高硬度氨氮废水.结果表明,在倒极操作下,Ti/RuO2-Ir2-RhOx电极加速寿命高达1 400h,分别是Ti/RuO2-TiO2与Ti/IrO2-Ta2O5电极的47倍与23倍.物理化学表征结果表明,RuO2-IrO2-RhOx涂层为致密均匀固溶体,表面有簇状晶粒析出.将研制的Ti/RuO2-IrO2-RhOx新型电极用于电解氨氮废水,发现其在析氯与氨氮去除方面均优于Ti/RuO2-TiO2和Ti/IrO2-Ta2O5.此外,氨氮浓度、电流密度以及初始氯离子浓度对氨氮去除效率均有明显影响.以上研究结果可为Ti/RuO2-IrO2-RhOx新型电极在氨氮废水的处理中的应用提供参考.

接触过滤技术是适合处理低浊水的方法之一.以接触絮凝理论为基础,研发一种两段式过滤装置,并考察两段式接触过滤法净化低浊水的过滤性能.研究表明:在原水浊度为20 NTU时,最佳絮凝剂为聚合氯化铝铁(PAFC),投药量为3mg/L;进水pH在6～8范围内时,出水浊度稳定于0.22～0.32 NTU之间;综合分析过滤周期、平均出水浊度与产水量,确定最佳过滤流速为10m/h.对于浊度为5～20 NTU间的低浊水,两段式接触过滤法具有良好的处理能力,平均出水浊度小于0.30 NTU.

In our previous works, membrane-free electrodeionization (MFEDI), an original deionization technique to produce high-purity water, was invented. However, traditional ion exchange resins, the heart of MFEDI, cannot simultaneously achieve effective adsorption, easy electrical regeneration, and good conductivity. Previously, an amphoteric resin, quaternary ammonium-sulfonic acid resin (QA-SAR), that behaved as medium-strength acid resin, was proposed and applied to produce high-purity water with regeneration performance superior to that of traditional resins. Although the regeneration performance of QA-SAR was better than that of traditional resins, the ion-exchange capacity and conductivity were poor, which further resulted in poor effluent and high regeneration voltage. In view of this, a novel amphoteric resin containing more anionic groups than cationic groups and behaving as medium-strength basic resin, sulfonic acid-quaternary ammonium resin (SA-QAR), was proposed herein. It exhibited better regeneration performance and purification performance than traditional resins and QA-SAR. Under the same conditions, the effluent quality of the MFEDI system filled with SA-QAR remained stable and lower than 0.1 mu S/cm, with energy consumption of approximately 0.32 kWh/m(3) water, whereas the effluent quality of the system filled with 550A and the system filled with QA-SAR deteriorated quickly, with energy consumption of approximately 0.36 and 0.43 kWh/m(3) water, respectively.

The extensive evaporation-induced aggregation of scale inhibitors in the wastewater of recirculating cooling systems causes severe environmental pollution. In this study, Amino Trimethylene Phosphonic Acid (ATMP), an ordinary scale inhibitor, was degraded via electrochemical oxidation using a multi-layered Ti/IrO2-RhOx-TiO2/ alpha-PbO2/beta-PbO2 electrode. The electrochemical oxidation experimental results verified the superior electro-catalytic properties of the beta-PbO2 electrode. Accelerated lifetime tests suggested that Ti/IrO2-RhOx-TiO2/ alpha-PbO2/beta-PbO2 possesses a service lifetime of 201 h under a current density of 40000 A/m(2), which is 3.4-100.5 times as long as other beta-PbO2 electrodes reported by other researchers. Four major operational parameters, namely electrolyte, current density, initial ATMP concentration, and pH, were discovered to significantly affect the ATMP degradation rate and electrical efficiency. The direct oxidation mechanism predominated in the degradation process of ATMP, achieving a 55.11% and 38.82% removal efficiency in Na2SO4 and NaCl solutions, respectively. In addition, two possible degradation pathways of ATMP were proposed: induced by the breaking of either C-P or C-N bonds.

Anodic oxidation has been recognized as an attractive technique for wastewater treatment. However, polymeric product (PP) adsorption still remains to be an obstacle because currently available exogenous PP removal methods are either laborious or costly. To overcome such a problem, a Ti/RuO2-IrO2-RhOx has been artfully designed for periodic bipolar operation to realize in-situ PP desorption herein. Due to the RhOx-bridged pseudocapacitance enhancement, the electrochemical stability reduction problem of the conventional electrode in bipolar operation could be substantially eliminated. The PP adsorption mainly impacted the interfacial charge transfer of the electrode instead of the mass transfer of contaminant from the solution toward the electrode surface. Delightedly, the bipolar operation could effectively in-situ regenerate the poisoned electrode from PP adsorption due to the combined effects of OH- dissolution and H(2 )stripping, thereby essentially promoting the deep mineralization of degradation intermediates rather than further polymerization, with this promotion degree influenced by four factors (current density, initial contaminant concentration, bipolar frequency, and contaminant types). This further encouraged the successful establishment of a new bipolar completely mixed (BCM) model for theoretical guidance of efficient PP desorption during various contaminant degradation. This work might open up a brand new avenue for poisoned electrode in-situ regeneration from detrimental PP adsorption and provide mathematical model guidance for PP desorption.

Electrode polarity reversal has been widely employed to inhibit membrane fouling and induce scale detachment during electrodialysis and electrochemical precipitation, respectively. However, frequent polarity reversal shortens the lifetime of traditional dimensionally stable anodes. In this study, a novel titanium electrode that employed a ternary iridium, tantalum, and rhodium oxide mixture (Ti/IrO2-RhOx-Ta2O5) as an active electrocatalyst film was investigated for polarity reversal applications. It was found that the Ti/IrO2-RhOx-Ta2O5 electrode with an Ir/Rh/Ta molar ratio of 3:3:4 had a service lifetime of 1030 h in a 20 g L-1 Na2SO4 solution at a current density of 2000 A m -2 and a polarity reversal frequency of 12 h(-1). In contrast, a Ti/IrO2 -Ta2O3 electrode with an Ir/Ta molar ratio of 6:4 under the same conditions exhibited a service lifetime of only 27S h. Physicochemical characterization revealed that the Ti/IrO2-RhOx-Ta2O5 film has a compact microstructure, solid solution characteristics, and contains both Rh3+ and Rh3+ which contributes to the stability during polarity reversal. Moreover, the Ti/IrO2-RhOx-Ta2O5 electrode showed better chlorine evolution performance than the Ti/IrO2-RhOx-Ta(2)O(5 )electrode.

Previously, we invented and investigated membrane-free electrodeionization (MFEDI), a novel deionization technique that uses ion exchange resins as the critical material, for the production of high-purity water. However, the functional materials used in MFEDI are common resins that cannot simultaneously achieve effective adsorption, easy electrical regeneration, and good conductivity. For instance, strong acid resin, a cation exchange resin commonly used in MFEDI, cannot be easily electrically regenerated; weak acid resin can be easily regenerated, but has poor conductivity and adsorption properties. There are currently no available resins that can meet all of the requirements of conductivity, adsorption and regeneration properties. In this study, a novel amphoteric resin was prepared and characterised. This amphoteric resin contained much more cationic functional groups than anionic functional groups, behaving as a medium-strength acid resin due to the introduction of anionic functional groups. The prepared amphoteric resin exhibited better purification property than weak acid resin, and could be electrically regenerated more easily than strong acid resin. When the amphoteric resin was coupled with strong base resin and the conductivity of the purified water was kept below 0.10 & micro;s/cm, the water recovery and energy consumption were 74.60% and 0.84 kWh/m3 water, respectively. By contrast, the energy consumption and water recovery were 40.74% and 2.65 kWh/m3 water for strong acid resin, and 64.44% and 1.53 kWh/m3 water for weak acid resin under similar conditions. Clearly, the developed amphoteric resin significantly improves the MFEDI properties.

In recent decades, electrochemical method has attracted growing attention for pollutant oxidation. The electrode is the kernel of an electrochemical system. However, currently available inactive anodes either lack conductivity or are expensive, whereas active anodes usually produce fewer hydroxyl radicals. Furthermore, the bipolar operation, which is frequently used for periodic anode cleaning, will significantly shorten the electrode lifetime. In this study, a pseudocapacitive Ti/RuO2-IrO2-RhOx has been proposed and investigated for the oxidation of phenol to overcome the above limitations. Bipolar accelerated life experiments showed that the service life of Ti/RuO2-IrO2-RhOx was 638 h, which was 3.5 times longer than that of conventional Ti/RuO2-IrO2. Physicochemical and electrochemical characterization indicated that the super-stable nature of polarity reversal obtained in Ti/RuO2-IrO2-RhOx was the consequence of catalyst redox reversibility enhancement, bonding reinforcement, catalyst conductivity improvement and microstructure optimization. Degradation results demonstrated that Ti/RuO2-IrO2-RhOx achieved 1.2-2.7-fold higher oxidation efficiency than Ti/RuO2-IrO2, which was primarily attributable to the improved oxidation of high-valence metal oxides rather than hydroxyl radicals. In addition, owing to the enhanced removal of polymeric products adsorbed on the electrodes, the bipolar operation outperformed the conventional monopolar operation in terms of oxidation efficiency.