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Due to the rapid expanding of plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and electric vehicles (EVs), the projectfed demand for lithium-ion batteries (LIBs) is huge and might result in supply risks for natural lithium-containing reserves. After the service life, spent LIBs continuously accumulate in the market, and they are excellent secondary resources for lithium recovery. To alleviate resource shortage and to decrease potential environmental pollution caused by improper solid waste disposal, recycling of spent LIBs is motivated world widely in recent years. Previous studies have usually focused on the recovery of cobalt and nickel, which create high economic benefit. Recovery of lithium, however, has not been highlighted. In this article, state-of-the-art on spent LIBs recycling is discussed with emphasis on lithium recovery. In addition to understanding underlying mechanisms and physiochemistry features of various recycling methods, the possibility for industrial realization of each method is also evaluated. The complex processing steps limit the industrial implementation of hydrometallurgy-dominant methods, which usually reclaim lithium in the last step, resulting in a poor recovery efficiency of lithium. The pyrometallurgy-dominant approach is readily to scale up but lithium is lost in the slag phase. Therefore, the mild recycling (cleaner production) methods are recommended for future study since they take advantages of traditional pyrometallurgy and hydrometallurgy, and could decrease treatment temperature as well as acid/alkaline usage. Image 1 • More efforts are appealed to recycle electrolyte with respect to lithium recovery. • Lithium is usually the last metal to recycle in hydrometallurgical methods. • Pyrometallurgical methods should decrease lithium lost and energy consumption. • External field assisted pyro combined with hydro methods are promising. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) is an attractive membrane material due to its superior chemical resistance, thermal stability and strong hydrophobicity. However, PTFE hollow fiber membranes are challenging to produce by conventional technique due to the high solvent resistance and high melt viscosity of PTFE. In this study, novel PTFE hollow fiber membranes composed of pure PTFE nanofibers were firstly fabricated via a scalable and environment-friendly method based on emulsion electrospinning with a non-rotating collector and followed by a high-temperature sintering process. The effects of PTFE/PEO mass ratio and sintering temperature on the morphologies and properties of the resulting membranes were investigated. The prepared PTFE hollow fiber membrane shows the excellent characteristics combining the advantages of both electrospun nanofibers membrane and hollow fiber membrane, such as high porosity (more than 82%), self-supporting and superhydrophobicity. The membrane sintered at 380 °C present the highest mechanical strength, which shows the tensile strength, Young's modulus, strain at break of 30.5 Mpa, 53 Mpa, and 315%, respectively. The permeate flux of the prepared PTFE hollow fiber membrane is about 4.6–8.8 times as that of the commercial PTFE hollow fiber membranes, as well as is approximately 3.2–11.6 times higher than the date of the reported PTFE hollow fiber membranes. Additionally, the prepared membrane shows high and stable flux in long-term and rising salinity experiments, indicating it is very promising for membrane distillation (MD) application and even for the treatment of hyper-saline wastewater. Image 1 • Novel hollow fiber membranes composed of pure PTFE nanofibers. • Scalable and environment-friendly method was proposed. • Membranes are high porous, self-supporting and superhydrophobic. • 3.2–11.6 times higher than the flux of reported PTFE hollow fiber membranes. • Stable and high flux in treatment of hyper-saline wastewater. [ABSTRACT FROM AUTHOR]

Highlights • Welding electrospun hollow fiber membrane is firstly applied in ammonia removal. • The effect of membrane thickness on selectivity was intensively investigated. • Self-made membrane with high flux and selectivity favors ammonia recovery. • Self-made membrane demonstrates its potential in membrane absorption application. Abstract Excessive ammonia nitrogen in wastewater seriously endangers ecological environment, so high-flux and selectivity membrane is urgently needed for ammonia removal using membrane absorption (MA). In this paper, a high-performance electrospun hollow fiber membrane was fabricated and solvent vapor welding treatment was adopted to enhance mechanical strength. The post-treatment membrane showed 103.8% higher in the Young's modulus than the pristine membrane. High mechanical strength, porosity and hydrophobicity of the membrane make it superior in mass transfer and selectivity. The effects of membrane thickness, pH and temperature of feed solution on experimental overall mass transfer coefficient (K OE) and selectivity coefficient (S NH3/H2O (g)) were intensively investigated to examine the membrane performance in MA application. The results show K OE is 1.35 * 10−5 m s−1 and S NH3/H2O (g) is 7.58 when pH is 11, which are higher than that of commercial membrane. Moreover, the selectivity can be improved greatly from 6.91 to 9.74 by increasing the thickness of the hollow fiber membrane from 55 ± 5 μm to 115 ± 5 μm. The welded electrospun hollow fiber membrane demonstrates great potential for ammonia removal in MA application. [ABSTRACT FROM AUTHOR]

• Hierarchical sphere-like LMO perovskite hybrids were prepared for O 3 activation. • Oxygen vacancies (OV) and multi-valence Mn were the main Lewis acidic sites. • DFT studies revealed OV and multi-valence Mn as active sites for O 3 decomposition. • Generated reactive species, O 2 −, OH and 1O 2 , were possible for BTA degradation. La-based perovskites are catalytically active owing to the oxygen vacancies, redox metal centers of B sites and surface hydroxyl groups. Nevertheless, the insights into these active centers on environmental catalysis are still insufficient. In this study, hierarchical mixed oxides perovskite microspheres were synthesized for catalytic ozonation over oxalic acid and benzotriazole. LaMn 4 O x , with LaMnO 3-δ as the dominant crystal phase, demonstrated superior catalytic activity to Mn 2 O 3 and LaMnO 3 synthesized from citric acid sol-gel method. Temperature-programmed desorption of NH 3 (NH 3 -TPD) and pyridine-Fourier transform infrared spectroscopy (pyridine-FTIR) tests proved Lewis acid as the main acid type. Temperature-programmed reduction of H 2 (H 2 -TPR), O 2 -TPD and X-ray photoelectron spectroscopy (XPS) analysis indicated the presence of oxygen vacancies and mixed valences of Mn in the crystal structure facilitated the catalytic process. Moreover, the content of oxygen vacancy was calculated by iodometric titration method. With the aid of theoretical calculations, oxygen vacancies were found to exhibit a strong affinity toward ozone adsorption, where ozone molecules spontaneously dissociated into reactive oxygen species (ROS) such as O 2 − and 1O 2. The B site of Mn facilitated ozone decomposition by extending the O O bond of ozone due to the electron transfer from Mn3+/Mn4+ redox cycle. In-situ EPR and quenching tests confirmed the contribution of O 2 − and 1O 2 in benzotriazole degradation along with OH. This study stepped further to unveil the ozone adsorption/decomposition and ROS generation on nanoscale perovskite-based composites. [ABSTRACT FROM AUTHOR]

• The natures of MOCVD dust have been obtained by comprehensive characterizations. • The distributions of GaN and metallic indium phase are crucial to metal recycling. • Some treatment strategies for MOCVD dust are preliminarily evaluated and discussed. • 89.59% of gallium is selectively leached using NaOH. Gallium (indium)-bearing dust generated from semiconductor industry is an important secondary resource for critical metal recycling. However, the diverse and distinct physicochemical natures of such waste material have made its recycling less effective, e.g. low extraction rate and complex treatment procedures. This research is devoted to gaining in-depth knowledge of the physical and chemical properties of such waste, including the chemical composition, physical phases, particle size distribution and chemical-thermal properties with a series of technologies. As a consequence, the occurrence and distribution of GaN and metallic indium phases are found to be crucial to efficient metal recycling. The thermal-chemical behavior shows that continuous oxidation occurred in the air atmosphere, indicating that heat-treatment followed by acid leaching is feasible to improve their recycling efficiencies. This process is able to leach 80.35% of gallium and 95.78% of indium with one-step operation. Furthermore, different treatment strategies for the waste material are preliminarily evaluated and discussed for the aim of metal recovery. The results show that gallium can be selectively recycled with recycling rate of 89.59% using alkaline leaching. With this research, the understanding on the recyclability of different metals and possibilities of selective recovery can be improved. It provides guidelines during the stage of decision-making for critical metal recycling in order to achieve efficient resource circulation. [ABSTRACT FROM AUTHOR]

Abstract Coal gasification wastewater (CGWW) is a typical toxic and refractory industrial wastewater. Here, a novel phenol and ammonia recovery process (IPE) was employed for CGWW pretreatment, and the coupled system assemble by the IPE process with A2/O system (IPE-A2/O) were operated to enhance the treatment performance of CGWW. The results showed that the IPE pre-treated effluent had a higher BOD 5 /COD ratio and lower refractory compounds compared to a typical process (MIBK). Subsequent A2/O biological treatment indicated that the A2/O-p system (A2/O system followed IPE process) obtained a higher average COD removal of 92% compared to 87.7% of the control (A2/O-m, A2/O system followed MIBK). The GC–MS analysis suggested that the content of alkanes in the IPE-A2/O effluent was lower than that of the MIBK-A2/O. The high-throughput sequencing revealed Levilinea, Alcaligenes , Acinetobacter , Thauera and Thiobacillus were the core genera in A2/O system. The genera Alcaligenes , Acinetobacter , Thauera and Thiobacillus in the degrading consortium were enriched in the A2/O-p system, leading to increased removals of organic pollutants and TN. These results suggested that the IPE process was a feasible pretreatment method, and the coupled IPE-A2/O system was an alternative technique for treating CGWW. Graphical abstract Unlabelled Image Highlights • A novel phenol and ammonia recovery process was employed to treat real CGWW. • The pre-treated process significantly improved the effluent biodegradability. • The pre-treated process facilitated the COD removal in A2/O system. • Microbial community structure was shaped by the pre-treated wastewater. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Develop a potential pathway for effective lithium recovery from low concentrated lithium-containing solution and preparation of industrial grade Li 2 CO 3. • The global lithium recovery rate reaches 97.4% and Li 2 CO 3 is obtained with a purity of 99.01%. • The ultrasound mechanisms and kinetics of lithium precipitation are investigated. Abstract Lithium carbonate (Li 2 CO 3), one of the most important lithium compounds, is usually prepared from lithium-containing solution. The lithium recovery rate and the purity of Li 2 CO 3 are highly dependent on the lithium concentration. In order to get a high lithium recovery rate, high concentrated lithium-containing solution is required, while the purity of Li 2 CO 3 can be low remaining a significant amount of impurities. Usually, it is not possible to obtain high purity Li 2 CO 3 by single-step precipitation with a relatively high lithium recovery rate especially from a low concentrated lithium-containing solution. In this research, ultrasound is introduced to increase lithium recovery rate and prepare industrial grade Li 2 CO 3. The research found that ultrasound can significantly reduce the polymerization of Li 2 CO 3 crystal particles and promote dissociation of impurity ions. At the same time, ultrasound accelerates the nucleation process of Li 2 CO 3 and boosts lithium recovery rate because of cavitation. The different parameters during the Li 2 CO 3 precipitation process were systematically discussed. Under the optimized conditions, the lithium recovery rate can be increased by 12% with a global lithium recovery rate of 97.4%. Li 2 CO 3 with a purity higher than industrial grade can be obtained by one-step precipitation. It demonstrates a potential pathway for effective lithium recovery from low concentrated lithium-containing solution and preparation of industrial grade Li 2 CO 3. [ABSTRACT FROM AUTHOR]

Abstract Sustainable growth of the lithium-ion battery (LIB) industry requires a safe supply of raw materials and proper end-of-life management for products. The lack of research on domestic critical raw materials and on management systems has limited the formulation of relevant policies for LIB-related industries. Here, a critical raw material (CRM) evaluation model was developed to identify the criticality associated with the supply risk (SR) and economic importance (EI) of different materials for the Chinese LIB industry. Dynamic materials flow analyses of the relevant critical materials were carried out by integrating a trade-linked model. Criticality analysis identifies the importance of different materials and optimizes the subsequent materials flow analysis. The results showed that the in-use stocks share large portions of material flow for Li, Ni, Co and graphite and further suggests that the market will not be saturated before 2025. For the end-of-life stage, less than 40 wt% of the materials in LIBs can be recycled under the current scheme of materials flow in China; this finding puts significant pressure on proper waste management. Consequently, it is very important to identify effective methods for utilizing the growing amount of waste materials and to provide a resource supplement for the Chinese LIB industry. This research provides guidelines for improving management strategies relevant to the critical materials in the LIB industry, for increasing resource efficiency, and for managing critical resources. Graphical abstract Image 1 Highlights • MFA for multiple elements in LIB industry is still scattered. • A CRMs evaluation system was proposed to optimize the further MFA. • Sankey diagrams of Li, Co, Ni and C reveal their status in Chinese LIB industry. • The stock and obsolete amount from 2012 to 2025 were estimated and forecasted. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • δ -MnO 2 and γ -MnO 2 showed different APAP removal kinetics at different pH. • Strong acidity largely promoted the APAP removal by MnO 2 , especially for γ -MnO 2. • Low pH values promoted nucleophilic addition and dimerization of APAP by MnO 2. • Dimerization and hydrolysis-oxidation were two major APAP transformation pathways by MnO 2. • Low pH values largely decreased the environmental risk of APAP transformation products by MnO 2. Abstract Manganese dioxides (MnO 2) govern the polymerization of phenolic and anilinic pollutants in nature water body. The studies on the chemistry of different phases of MnO 2 was relatively limited. Here we compared two MnO 2 , layer δ -MnO 2 and tunnel γ -MnO 2 , on their reaction kinetics and removal pathways with acetaminophen (APAP) as model compound. We found the kinetics of acetaminophen transformation by MnO 2 were largely influenced by pH values and MnO 2 structures. In neutral systems, APAP removal by δ -MnO 2 was faster than by γ -MnO 2. This was attributed to the higher catalytic potential of δ -MnO 2. In acidic systems, APAP removal by γ -MnO 2 was faster than by δ -MnO 2. This was attributed to the larger surface area and weaker electrostatic repulsion of γ -MnO 2 to APAP in acidic conditions. Furthermore, the pathways of acetaminophen transformation were influenced by pH values. Dimerization and hydrolysis-oxidation were the two major APAP transformation pathways by both MnO 2 in neutral and acidic systems. Low pH values induced the nucleophilic addition between quinoneimine (the product of hydrolysis-oxidation) and anilines (e.g. , APAP and its dimers). Low pH values also promoted the dimerization degrees of APAP. The hydrophilicity of APAP transformation products by MnO 2 were significantly reduced by low pH values. This work reconsidered the significances of acidity in the pollutants transformation by MnO 2 , and provided new perspectives to study the pollutants transformation by different phases of MnO 2. [ABSTRACT FROM AUTHOR]

Abstract Five negatively charged organic compounds with different structures, sodium methane sulfonate (MS), sodium benzene sulfonate (BS), sodium 6-hydroxynaphthalene-2-sulfonate (NSS), sodium dodecyl sulfate (SDS), and sodium dodecyl benzene sulfonate (SDBS), were used to examine the fouling of an anion exchange membrane (AEM) in electrodialysis (ED), to explore the effect of molecular characteristics on the fouling behavior on the AEM and changes in the surface and electrochemical properties of the AEM. Results indicated that the fouling degree of the AEM by the different organics followed the order: SDBS > SDS > NSS > BS > MS. SDBS and SDS formed a dense fouling layer on the surface of the AEM, which was the main factor in the much more severe membrane fouling, and completely restricted the transmembrane ion migration. The other three organics caused fouling of the AEM by adsorption on the surface and /or accumulation in the interlayer of the AEM, and exhibited almost no influence on the transmembrane ion migration. It was also concluded that the organics with benzene rings caused more severe fouling of the AEM due to the stronger affinity interaction and steric effect between the organics and the AEM compared with organics with aliphatic chains. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An available method was developed for characterization of vanadate species combined with ESI-TOF-MS and thermodynamics. • Evolutions of four characteristic vanadium species were comprehensively studied in acidic and neutral conditions. • The thermodynamic models were established and phase diagram was visualized for vanadium chemical speciation. • The semi-quantitative method is supposed to be effective for understanding of vanadium speciation in environmental fields. Abstract Identification the polymerization nature of vanadium bearing solution is difficult, yet it is of great environmental concern due to the possible carcinogenic effects as well as high-value sustainable necessities. Thus, seeking for simple and efficient characterization methods of tracking vanadium species is in urgent demand. In this work, high-resolution electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) coupled with thermodynamic calculations was employed to measure vanadium-containing samples. Evolutions of four characteristic vanadium species, H 2 VO 4 − (0–1%), V 2 species (0–1%), V 4 species (1–20%), and V 10 species (60–95%), were comprehensively studied from acidic to neutral conditions, based on which thermodynamic model and vanadium phase diagram were established to visualize transformation pathways. More than 30 types of aqueous vanadium species could be semi-quantitatively detected by employing this method with less than 5% relative error, and the corresponding existing forms and concentration of these vanadium species could be well predicted. The vanadium species identified in MS results were confirmed by NMR. This method can be widely used for the understanding of vanadium speciation in practical examples, especially involving V(V), Cr(VI) ions or organic complexes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A process to directly regenerate spent LiNi 1/3 Co 1/3 Mn 1/3 O 2 is demonstrated. • This process incorporates mechanochemical activation and solid-state sintering. • This method can restore the layered structure and improve lithium ion diffusion. • Secondary pollution will not be introduced in this regeneration process. • The economic viability of this method is better than a metallurgical process. Abstract The production of lithium-ion battery is around 9100 million sets in 2016 and is believed to further increase consecutively. This fact triggers the generation of spent cathode materials which contain metals of both valuable and hazardous. Their recycling corresponding to life cycle sustainability of lithium-ion battery has attracted significant attention. However, most technologies for recycling waste lithium-ion batteries are dependent on metallurgical based processes where secondary pollution is inevitable. This research demonstrates a process to directly regenerate LiNi 1−x−y Co x Mn y O 2 cathode material by incorporating methods of mechanochemical activation and solid-state sintering, which can restore the layered structure and improve the lithium ion diffusion without introducing extra impurities. By understanding the effects of sintering temperature, the optimal conditions for direct regeneration of cathode materials with obvious improvement on electrochemical performance can be obtained. As a result, this research proves the possibility of direct regeneration of nickel-containing waste cathode materials with minimized chemical consumption. [ABSTRACT FROM AUTHOR]

Fluorescent nanoarchitectures, such as hydrophobic micelles and hydrophilic vesicles decorated with fluorescent carbon nanoparticles, were fabricated from one fatty acid by means of photo-triggering. The biomimetic nanostructures, like cell membrane structures, have applications in fluorescence imaging in both the cell cytoplasm and nucleus. Besides, hydrophobic micelles can be used as very stable fluorescent inks. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Atomic Co/Ni dual sites in N-doped porous Janus-like carbon frameworks is successfully constructed. • Co/Ni dual sites electrocatalysts exhibit good ORR and OER bifunctional performance. • The formation of Ni N bond increases the electronic activity of N atoms. • Different active sites in Janus-like electrocatalysts for ORR and OER. Abstract Single-atom electrocatalysts have attracted board interest in the recent years as they combine the advantages of heterogeneous and homogeneous electrocatalysts. Nevertheless, single-atom electrocatalysts with single metal component cannot further satisfy the demand of catalytic properties. This work developed atomic Co/Ni dual sites in N-doped porous carbon Janus-like frameworks through epitaxial growth of cobalt based MOFs on nickel complexes. Structural characterization and atomic-scale transmission electron microscopy revealed the homogeneously dispersed active sites of Co-Ni alloy and single Co/Ni atoms. Electrochemical data strongly demonstrated the advantages of integrating Co-MOF and Ni complex with different topological structures to form a Janus-like structure. The resultant catalysts afforded onset potential of 0.93 V and half-wave potential of 0.84 V for oxygen reduction reaction in alkaline media, and 0.86 V and 0.73 V in acid media, which is better than single noble-metal-free catalysts, even close to commercial Pt/C. Besides, the catalysts also exhibited good oxygen evolution reaction performance (a current density of 10 mA cm−2 at a potential of 1.59 V) and overvoltage between ORR and OER is 0.78 V. Density functional theory calculations indicated the high electrocatalytic activities are originated from the synergetic effect of atomic Co/Ni -N- C bonds and microstructure of the prepared materials. This work paves a new avenue for the development of multiatomic electrocatalysts for energy conversion. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Asymmetric MCDI with only anion-exchange membrane (AMCDI-AEM) is proposed. • AMCDI-AEM shows better performance compared with CDI. • AEM with high IEC and low resistance and water uptake favors desalination. • AEM plays a stronger role than CEM in membrane-assisted CDI application. Abstract Membrane capacitive deionization (MCDI) usually contains both anion and cation exchange membranes (AEM, CEM) to restrict the ion desorption during charging and re-adsorption during discharging in capacitive deionization (CDI). In this study, different from conventional MCDI, an asymmetric membrane capacitive deionization (AMCDI) device packing an AEM only (AMCDI-AEM) was constructed, where the AEM was lab-synthesized from poly (2, 6-dimethyl-1, 4-phenylene oxide). The effect of the AEM properties, such as ion exchange capacity, water uptake and membrane resistance on the desalination performance of AMCDI-AEM was systematically discussed. The results indicate that an AEM with high ion exchange capacity, low membrane resistance and low water uptake is beneficial for AMCDI-AEM. Furthermore, AMCDI packed with a commercial cation exchange membrane only (AMCDI-CEM) and a conventional MCDI device were also assembled to stress the importance of AEM application. Although the charge efficiency of AMCDI-AEM is lower than a full MCDI cell (54.7 vs 95.0%) due to the unprotected cathode, AMCDI-AEM device shows comparable salt adsorption capacity to MCDI (7.4 vs 7.2 mg g−1), and is much better than that of CDI (2.3 mg g−1) and AMCDI-CEM (1.5 mg g−1), suggesting that AEM plays a stronger role than CEM for membrane-assisted CDI application. By using a single AEM and commercial activated carbon electrode, this work provides an opportunity to reduce membrane cost for the industrialization of MCDI technology. [ABSTRACT FROM AUTHOR]

Abstract The recovery of polyoxovanadate acid compounds has got increasing attention because of both sustainable necessities and material applications. In this paper, we proposed a recovery strategy of ammonium substituted polyoxovanadate acid compounds (ASPOVC) by solvent extraction from leaching/aqueous solution. It is noted that the state of the compound (solid or liquid) is possibly controllable by the type of amines (branched or linear amine chains), enlarging application fields of these compounds. Subsequently, the compounds were characterized by comprehensive techniques, from which the molecular structures with hydrogen bonds were described. The solubility parameters were calculated, and solid ASPOVC was the biggest among the four compounds, explaining formation reasons of different states. The amine extractants performed well-efficiency (more than 98.5%) for reutilization. This approach is believed to be promised for a sustainable recovery for high-value vanadium materials from waste water. Graphical abstract Image Highlights • A recovery strategy of ASPOVC was developed by solvent extraction. • The state of the compound was controllable by the type of primary amine. • The hydrogen bond extraction mechanism was verified by NMR and FTIR. • The solubility parameters were calculated, of which solid state compound was the biggest. [ABSTRACT FROM AUTHOR]

Abstract A novel surface modified anion exchange membrane (AEM) was prepared by electrodeposition of graphene oxide (GO) and polydopamine (PDA) coating, aiming at improving antifouling performance and stability. The AEM was firstly modified by electrodeposition of GO and then immersed into the dopamine solution to form a thin PDA layer. The effects of GO and PDA composite modification were investigated by various analytical techniques and electrodialysis application. The GO@PDA-modified AEM (GO@PDA-M) exhibited highly hydrophilic and negatively charged. In addition, the introduction of PDA coating helped to construct a smoother and denser composite modifying layer composed of GO and PDA, and reduced the roughness of membrane surface. Depending on these properties, the GO@PDA-modified AEM showed significant antifouling ability without compromising the desalination performance. After being fouled by 150 mg/L sodium dodecyl benzene sulfonate (SDBS) for 4 h, the desalination rate of GO@PDA-M increased by 39.3% compared to pristine membrane, while for PDA-modified membrane (PDA-M) and GO-modified membrane (GO-M) were 5.7% and 18.2% respectively. Moreover, it still maintained antifouling ability after 20 h of continuous operation. The stability of GO@PDA-M was immensely improved compared with the GO-M due to the introduction of PDA layer. Highlights • Anion exchange membrane was surface modified by electrodeposition of GO and PDA coating. • GO@PDA-modified membrane was highly hydrophilic and negatively charged. • Introduction of PDA coating help construct a smoother and denser modifying layer. • GO@PDA-modified membrane exhibit significant improving of antifouling and stability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • O 3 shows a dual role in photocatalytic ozonation process. • The introduction of O 3 overcomes the drawback of the photocatalysts. • Higher CB position benefit the activity of photocatalysts in the Vis-O 3 system. • Acid solution is beneficial for the photocatalytic ozonation. • WO 3 is also found to be active in catalytic ozonation process. Abstract Photocatalytic ozonation has great potential in wastewater treatment. However, the role of ozone and the contribution of photogenerated hole in this process have not been fully understood. Here three WO 3 materials are synthesized and used as model catalysts in visible-light photocatalytic ozonation for the mineralization of pharmaceutical pollutants. A dual role of ozone in this process has been confirmed: (i) direct oxidation of the pollutant till formation of refractory intermediates, (ii) efficient trapping of photoelectron that cannot be captured by O 2. The latter is crucial because it not only induces the O 3 −-mediated pathway for hydroxyl radical (OH) formation but also separates the hole which has proven to be capable of oxidizing water into OH. Evidenced by photoluminescence results, the intrinsic charge separation ability of WO 3 in photocatalytic ozonation is no more as important as that in photocatalysis with O 2. Finally, this process is more applicable under acidic condition. This work contributes to a better understanding of the significance of ozone in WO 3 photocatalytic ozonation and provides us an insight into the mechanism of photocatalytic ozonation. [ABSTRACT FROM AUTHOR]

A novel omniphobic nanofiber membrane for membrane distillation (MD) was successfully fabricated by one-step electrospinning of PVDF-HFP and fluorinated-decyl polyhedraloligomeric silsesquioxane (F-POSS) colloidal suspension solution. The fabricated F-POSS/PVDF-HFP membrane possessed uniform fiber structures and had extreme high F-POSS concentration on the surface. This F-POSS based membrane exhibited excellent omniphobicity, as indicated by its wetting resistance to different low surface tension liquids, including ethanol with a contact angle of 128.2°. Membrane distillation (MD) experiments showed that the water flux and water quality were stably maintained in highly saline feed solutions containing low surface tension substances, which successfully demonstrated its potential application for desalination of challenging industrial wastewater. [ABSTRACT FROM AUTHOR]

Novel nanofibers-covered hollow fiber membrane (N-HFM), combining the advantages of both electrospun nanofibers film and hollow fiber membrane was fabricated via electrospinning with non-rotational collectors. The key parameters of electrospinning including positive voltage, negative voltage, polymer concentration and working distance were optimized to examine their effects on the morphology and structure of N-HFM. Meanwhile, a solvent vapor welding post-treatment was firstly applied to enhance the mechanical strength of hollow fiber membranes. The welding can improve the mechanical property and water repellency as well as maintain the high porosity, by fusing the nanofibers just at junctions. After a 40 min welding, the Young's modulus, strain at break and tensile strength of the welded N-HFM increased by 117%, 79% and 90% respectively, compared to the pristine N-HFM. Furthermore, the welded N-HFM was able to present a high flux of 13.2 L m −2 h −1 and a stable salt rejection of over 99.9% during the 5 h of direct contact membrane distillation (DCMD) test, suggesting the competency of the welded N-HFM for MD applications. [ABSTRACT FROM AUTHOR]

Coal gasification wastewater is a typical high phenol-containing, toxic and refractory industrial wastewater. Here, lab-scale anaerobic-anoxic-oxic system was employed to treat real coal gasification wastewater, and methanol was added to oxic tank as the co-substrate to enhance the removal of refractory organic pollutants. The results showed that the average COD removal in oxic effluent increased from 24.9% to 36.0% by adding methanol, the total phenols concentration decreased from 54.4 to 44.9 mg/L. GC-MS analysis revealed that contents of phenolic components and polycyclic aromatic hydrocarbons (PAHs) were decreased compared to the control and their degradation intermediates were observed. Microbial community revealed that methanol increased the abundance of phenolics and PAHs degraders such as Comamonas , Burkholderia and Sphingopyxis . Moreover, functional analysis revealed the relative abundance of functional genes associated with toluene, benzoate and PAHs degradation pathways was higher than that of control based on KEGG database. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A sustainable process for recycling spent lithium-ion batteries was proposed. • A stable (easy to transport and store) and cheap reductant was studied. • Using ammonia chloride as reductant is a win-win solution. Abstract In this paper, a sustainable process to recover valuable metals from spent lithium ion batteries (LIBs) in sulfuric acid using ammonium chloride as reductant was proposed and studied. Being easily reused, ammonium chloride is found to be efficient and posing minor environmental impacts during the overall process. By investigating the effects of a wide range of parameters, e.g., H 2 SO 4 concentration, NH 4 Cl concentration, temperature, leaching time, and solid-to-liquid mass ratio, the leaching behaviour of Li, Ni, Co, and Mn was systematically investigated. And the leaching mechanism and kinetics were determined by mineralogically characterization of residues at various reaction times and by fitting using different kinetic models. With this research, it is possible to provide a win-win solution to improve the recycling effectiveness of spent LIBs by using waste salt that is easily reused as the reductant. [ABSTRACT FROM AUTHOR]

Photocatalytic generation of •OH from O3 is an intriguing avenue for aqueous organics degradation due to the high utilization of photogenerated electrons, but ambiguous information about charge transfer and surface‐active sites hinders the optimization of photocatalysts. In this work, a series of cobalt single‐atom catalysts (SACs) anchored on graphitic carbon nitride to improve •OH generation from O3 via electron reduction and catalytic activation dual pathway is synthesized. Various characterization and density functional theory calculations reveal that cobalt single atoms can introduce trap states for holes, which improve the light‐harvesting ability and accelerate the transfer of electrons and holes. Meanwhile, Co single atoms can also act as active sites to accelerate ozone decomposition and produce •OH directly. Particularly, the influence of different surface densities of Co single atoms on photogenerated electron supply and surface reaction is disclosed. A higher density of Co provided more active sites for O3 catalytic activation, but the narrowed distance between oxidation and reduction centers reduces the supply of available electrons by worsening the charge recombination. This work offers an atomic‐level correlation of the isolated metal density and photocatalytic properties, and can scientifically guide the design of high‐performance photocatalysts for organic synthesis and water purification. [ABSTRACT FROM AUTHOR]

This study demonstrates the feasibility of layer-by-layer (LbL) assembly of poly(sodium 4-styrene sulfonate) (PSS)/poly(diallyldimethylammonium chloride) (PDADMAC) polyelectrolyte multilayers on an anion exchange membrane (AEM). The electrodeposition of (PSS/PDADMAC) n multilayers on the AEM with a PSS layer as the top surface endows the surface with negative charges and increases the surface hydrophilicity, leading to a significantly improved antifouling performance in electrodialysis (ED) to an organic foulant, i.e., sodium dodecyl sulfate (SDS). The desalination rate during 180 min increased from 24.0% for the pristine AEM to 30.5% for a 5.5 PSS/PDADMAC bilayers modified AEM with 75 mg/L SDS in the initial solution. A SDS fouling layer was formed at the dilute side of the pristine AEM, causing a sharp increase of electrical resistance and restricting the ion transport through the AEM completely. Electrodeposition of 5.5 PSS/PDADMAC bilayers prevented the formation of the SDS fouling layer at the surface of AEM, which reduced the sharp increase of electrical resistance and kept the ion transport through the AEM unaffected. With 100 or 150 mg/L SDS in the initial solution, the desalination rate during 180 min increased from 24.1% or 15.4% for the pristine AEM to 28.4% or 26.8% for the 5.5 PSS/PDADMAC bilayers modified AEM. [ABSTRACT FROM AUTHOR]

In recent years, the recovery of metals from spent lithium ion batteries (LIBs) has become increasingly important due to their great environmental impact and the wastage of valuable metallic resources. Among different types of spent LIBs, processing and recycling the spent LiFePO4 batteries are challenging because of their relatively low extraction efficiency and recycling selectivity of valuable metal(s) and great potential for secondary waste generation. In this research, an effective and sustainable approach for selective leaching of lithium from spent LiFePO4 batteries was demonstrated. By properly adjusting or controlling the oxidative state and proton activity of the leaching solution, lithium was found to be selectively leached with a high recovery efficiency. The aluminium remained in the metallic form and iron as FePO4 in the solid residue which can be easily separated by sieving. The effects of a range of parameters (i.e. acid concentration, initial volume fraction of the oxidant, liquid-to-solid ratio, reaction temperature and time) during lithium leaching were comprehensively investigated. The selective reaction mechanisms were clarified and the controlling step for the leaching kinetics was identified. Based on the laboratory scale results, a pilot batch process was developed and simulated. The process is found to be techno-economically feasible and environmentally friendly for recycling of spent LiFePO4 batteries using selective leaching. High purity Li2CO3 (99.95 wt%) could be obtained with a high recovery rate. This research demonstrates the possibility of improving the metal recycling effectiveness from spent LiFePO4 batteries by incorporating the principles of green chemistry and probably contributes to the sustainability of the lithium ion battery industry. [ABSTRACT FROM AUTHOR]

The nitrogen heterocyclic compounds (NHCs) are very toxic and widely used in many industries, while the treatment of NHCs in wastewater has not attracted enough concern till now. Here we studied the complete degradation of a typical NHCs, benzopyrazole (BP), in wet oxidation. The effects of different operation parameters, such as stirring speed, temperature, reaction time and initial pH, on BP degradation and chemical oxygen demand (COD) removal were studied. BP was totally degraded and the COD removal efficiency achieved 76.7%, after 120 min reaction at 220 °C with initial pH 6.5. Meanwhile, 81.7% of the nitrogen from BP was removed from the solution. The toxicity of the BP solution was reduced by 95.2% after wet oxidation at 240 °C for 180 min. The influences of coexisted NO 3 − , CO 3 2− , SO 4 2− and PO 4 3− ions were also investigated. With quantum chemical calculation and intermediates analysis by electrospray ionization mass spectrometry, a very detailed degradation pathway of BP in wet oxidation was proposed. [ABSTRACT FROM AUTHOR]

The heterogeneous anion exchange membranes (AEMs) were modified by electrodeposition of graphene oxide (GO) under different conditions. The physicochemical properties of GO-modified membranes were characterized systemically to obtain the optimized conditions for the electrodeposition of GO on the surface of AEMs. The results indicated that the contact angle and zeta potential of the modified AEMs decreased when increasing the concentration of GO from 0.05 g/L to 0.1 g/L. The higher concentration of NaCl, as the supporting electrolyte, could hinder the electrodeposition of GO on the AEMs for the competitive migration between the GO and Cl − ions. The increase of current density had a positive effect on properties of GO-modified membranes in the range of 1–5 mA/cm 2 . Compared with the pristine AEM, all the GO-modified AEMs exhibited smoother surface, higher hydrophilicity and negative zeta potential. It was also found that the GO modifying layer did not increase electrical resistance and had only a negligible effect on the desalination performance of AEMs. In the fouling experiments with sodium dodecyl benzene sulfonate (SDBS) as the model foulant, the GO-modified AEMs exhibited improved fouling resistance to SDBS. [ABSTRACT FROM AUTHOR]

This paper deals with a systematic thermodynamic study on the liquid–liquid extraction of vanadium from aqueous solution (0.001–0.1 mol/kg) using primary amine N1923 (0.004–0.3 mol/kg). Suitable and practical thermodynamic models (Pitzer–Pitzer and Pitzer–Margules) were improved and verified for the first time. Firstly, the Pitzer parameters were correlated based on solid–liquid equilibrium data, and then employed as the initial values in regression progress. Finally, all the interaction parameters ( β aq 0 , β aq 1 , β RV , RV org , β R , RV org , β R , R org , A RV , R org , A tol , RV org and A tol , R org ) were regressed. Liquid–liquid equilibrium data were predicted using those parameters and compared to the experimental results, which confirmed the reliability and suitability of these models for the present system. Furthermore, these models provided excellent predictions of the effect of the initial amine molality and pH value on the extraction, showing great promise for industrial applications. [ABSTRACT FROM AUTHOR]

The annular centrifugal contactors (ACCs) have been used for liquid-liquid extraction in bench scale/pilot-plant tests. In view of good hydraulic properties and high mass-transfer efficiency, the state-of-the-art of extraction process using ACC/ACCs can satisfy the mass transfer enhancement, cascade and operational security liquid-liquid extraction processes. The many investigations of ACCs have been focused on the flow instabilities, multiphase flows, axial mixing, etc. The published literatures on these aspects have been critically analyzed and presented in a coherent manner. But in this review, the summaries of the application of ACCs in many specific extraction processes were presented, and how to optimize the operation conditions to reach good hydraulic properties were summarized using the designed equipments of ACCs. The good hydraulic properties were significant to the quick and excellent separation of the immiscible phase, and the high mass-transfer efficiency for liquid-liquid extraction were performed by cascade of ACCs. The advantages and disadvantages of the ACCs were discussed in detail. Recommendations have been made for future work with aim of more information for the application of the hydrometallurgical process. [ABSTRACT FROM AUTHOR]

End-of-life light emitting diode (LED) associated with its electronic product is a new type of electronic waste (E-waste) and contains considerable amounts of valuable and hazardous metals. Although the quantity of a single LED is small, the total number of end-of-life LEDs is extremely significant that requires proper management and recycling from both resource and environmental points of view. Particularly, metals recycling from electronic waste has been considered as a preferred option to ensure sustainable supply of critical materials. In this research, it demonstrates a methodology to evaluate the criticality and recyclability of various types of end-of-life LEDs. Two factors, i.e. the resource index and technology index, were introduced into identifying the criticality of different types of waste LEDs, which indicates the potentials for effective metals recycling. Furthermore, combined statistical entropy and grading, the recyclability is assessed to identify the viability for metals recycling from different types of end-of-life LEDs. The results of the proposed evaluation methodology suggest that green/high luminous intensity LED exhibits significant potential for metal recycling and blue/high luminous intensity LED exhibits the lowest recycling difficulty. The aims of the research are expected to assist manufacturers and policy-makers improving the recycling effectiveness of waste LEDs especially in the metals recycling stage and developing effective waste management systems and strategies in the end-of-life stage. [ABSTRACT FROM AUTHOR]

Recovery of metals from spent lithium-ion batteries (LIBs) has attracted worldwide attention because of issues from both environmental impacts and resource supply. Leaching, for instance using an acidic solution, is a critical step for effective recovery of metals from spent LIBs. To achieve both high leaching efficiency and selectivity of the targeted metals, improved understanding on the interactive features of the materials and leaching solutions is highly required. However, such understanding is still limited at least caused by the variation on physiochemical properties of different leaching solutions. In this research, a comprehensive investigation and evaluation on the leaching process using acidic solutions to recycle spent LIBs is carried out. Through analyzing two important parameters, i.e. leaching speed and recovery rate of the corresponding metals, the effects of hydrogen ion concentration, acid species and concentration on these two parameters were evaluated. It was found that a leachant with organic acids may leach Co and Li from the cathode scrap and leave Al foil as metallic form with high leaching selectivity, while that with inorganic acids typically leach all metals into the solution. Inconsistency between the leaching selectivity and efficiency during spent LIBs recycling is frequently noticed. In order to achieve an optimal status with both high leaching selectivity and efficiency (especially at high solid-to-liquid ratios), it is important to manipulate the average leaching speed and recovery rate of metals to optimize the leaching conditions. Subsequently, it is found that the leaching speed is significantly dependent on the hydrogen ion concentration and the capability of releasing hydrogen ions of the acidic leachant during leaching. With this research, it is expected to improve understanding on controlling the physiochemical properties of a leaching solution and to potentially design processes for spent LIBs recycling with high industrial viability. [ABSTRACT FROM AUTHOR]

Effective recycling of spent graphite from lithium-ion batteries (LIBs) has a strong application potential. In this research, anode scrap of spent LIBs is efficiently recovered and reused as high-performance cathode in electro-Fenton system. Role of different recovery processes in the reuse of anode scrap powder in electro-Fenton system is focused, including Anode raw powder (RP), acid leaching (AL), acid and alkali leaching (AAL) residual powder. The results indicate functional groups of anode powder are changed by different leaching processes, which can significantly affect the subsequent reuse in electro-Fenton system. According to evaluation by electrochemical characterization, the AAL has a higher hydrogen peroxide (H 2 O 2 ) selectivity and yield than RP and AL due to highly active two - electron reduction of oxygen (O 2 ). Interestingly, when anode powder is reused in electro-Fenton system, the AL electrode achieves 100% bisphenol A (BPA) removal in 70 min and 87.4% COD removal in 240 min, showing the best degradation efficiency. The reason can be attributed to higher carboxylic group content (35.83%) of AL powder than that of AAL (7%). Thus, part of iron ion in solution can be adsorbed on the surface of AL cathode, forming a partial heterogeneous iron oxidation-reduction. Furthermore, the reusability of AL electrode is evaluated. Compared with other carbon cathode, the AL cathode with a low current density still maintains 100% BPA removal after 10 reuse cycles. Since it is inherent with high reusability and environmental friendliness comparing with traditional cathode materials, this research demonstrates a potentially new approach to cooperatively treat pollutants from solid waste and waste water. [ABSTRACT FROM AUTHOR]

Recovery of valuable metals from spent lithium-ion battery (LIB) is of both environmental and economic importance. Acidic leaching usually encounters issues of low selectivity or slow kinetics with considerable secondary waste generation during further purification. In this research, a closed-loop process with improved leaching selectivity for recycling of spent LiNi x Co y Mn 1-x-y O 2 battery using weak acidic leachant was demonstrated. To obtain optimal conditions of the leaching process, the effects of acid concentration, solid to liquid (S/L) ratio, temperature and reductant content were systematically investigated. Almost all Co, Li, Mn and Ni could be effectively recovered into the solution while Al remained in the residue as metallic form, after one-step leaching. The role of reductant during leaching was further evaluated which was found to be critical for the leaching kinetics. It is clear that the addition of reductant could alter the rate-controlling step of leaching from the ion diffusion in the residue layer to the surface chemical reactions. With high selectivity against impurities, this research proposed and verified a process to recover high purity Li 2 CO 3 from the cathode scrap of LIBs, and more than 90% of the global recovery rate of valuable metals can be achieved. [ABSTRACT FROM AUTHOR]

Chinese steel industry faces increasing pressure to reduce water consumption and wastewater impact. To perform the optimization of steel production process from the perspective of water use, this work describes a new superstructure-based water network optimization model using typical steel park as our study use. The water systems at different scales ( e.g. unit-scale, plant-scale and park-scale) in the water network and their interactions are modeled for optimization. To construct the optimization model: 1) All types of unit-scale typical water systems in the park are identified, and short-cut unit models are developed as the basic elements for network superstructure; 2) Intra- and inter-plant superstructures are further established to describe potential configurations of the water network at plant-scale and park-scale respectively; 3) Built up on the element models and superstructures, a Mixed Integer Non-Linear Programming model using total annual cost as objective is set up to investigate potentials for water network optimization in a steel park. To illustrate its applicability and effectiveness, an industrial case study is carried out, in which two schemes are illustrated, one scheme (termed as scheme A) considering only indirect integration between plants, the other (termed as scheme B) considering both direct and indirect integration strategy (mixed integration). In scheme A, due to the higher water efficiency and optimal configuration in the case study, the freshwater consumption and total annual cost are reduced by 22% and 21% respectively. Scheme B shows 23% savings in total annual cost, while the reduction of freshwater consumption keeps unchanged. Besides, the information about the integration strategies of all scales ( e.g. unit-, plant- and park-scale) can all be obtained, which is valuable for decision-making. [ABSTRACT FROM AUTHOR]

The physicochemical and structural properties of the AMX (homogeneous AEM), AMA (semi-homogeneous AEM) and HAEM (heterogeneous AEM) were characterized systematically to examine their effects on membrane fouling from sodium dodecyl sulfate (SDS) in electrodialysis. Results demonstrated that the fouling of three AEMs was closely related to their membrane structure, and the denser membrane structure caused more SDS accumulated on the membrane surface to make the severer membrane fouling. The existence of SDS in the dilute solution caused the desalination rate of AMX, AMA and HAEM decreased by 42.3%, 15.3% and 9.2%, respectively. Different fouling layer was formed on the surface of AMX and AMA except HAEM, which was demonstrated firstly by element mapping of membrane cross-section. Electrochemical impedance spectroscopy (EIS) suggested the ionic migration through the fouled AMX was restricted completely, different from the transmembrane migration of partial ions through the fouled AMA and HAEM. Compared with the fouled AMA and HAEM, the performance of the fouled AMX caused by SDS was more difficult to be recovered due to its denser membrane structure. [ABSTRACT FROM AUTHOR]

In order to promote sustainable development, green and renewable clean energy technologies continue to be developed to meet the growing demand for energy, such as supercapacitor, fuel cells and lithium-ion battery. It is urgent to develop appropriate nanomaterials for these energy technologies to reduce the volume of the device, improve the efficiency of energy conversion and enlarge the energy storage capacity. Here, chitosan/cellulose carbon cryogel (CCS/CCL) were designed and synthesized. Through the introduction of zeolite imidazole frameworks (ZIFs) into the chitosan/cellulose cryogels, the obtained materials showed a microstructure of ZIF-7 (a kind of ZIFs) coated chitosan/cellulose fibers (CS/CL). After carbonizing, the as-prepared carbonized ZIF-7@cellulose cryogel (NC@CCL, NC is carbonized ZIF-7) and carbonized ZIF-7@chitosan cryogel (NC@CCS) exhibited suitable microspore contents of 34.37% and 30%, respectively, and they both showed an internal resistance lower than 2 Ω. Thereby, NC@CCL and NC@CCS exhibited a high specific capacitance of 150.4 F g −1 and 173.1 F g −1 , respectively, which were much higher than those of the original materials. This approach offers a facile method for improving the strength and electronic conductivity of carbon cryogel derived from nature polymers, and also efficiently inhibits the agglomeration of cryogel during carbonization in high temperature, which opens a novel avenue for the development of carbon cryogel materials for application in energy conversion systems. [ABSTRACT FROM AUTHOR]

For the purpose of the recovery of the high-purity vanadium product in leaching solution, solvent extraction has been considered as a promising approach. However, the vanadium species varied in different concentrations and pH values in aqueous solution, thus affecting the extraction yield or the reaction product in the process. In this paper, the main species of vanadium in solutions were determined with the equilibrium constants. The extraction reactions were determined based on determined species, then the hydrogen bond association mechanism of the reaction as well as the possible structures of the vanadium complexes were proposed and discussed in detail. This study established a systematic methodology for understanding the transition metal speciation in aqueous solutions as well as the extraction reactions, and envisaged the insights into the mechanism of the transition metal solvent extraction by primary amines. [ABSTRACT FROM AUTHOR]

The efficient and rapid selective extraction of V(V) from leaching solution with sulfated primary amine N1923 was demonstrated. In the single-stage extraction using annular centrifugal contactor (ACC), the influence of the total flow and the speed rotor on extraction percentage of V(V) was investigated using central composite design (CCD), and the results of experimental conditions were analyzed by analysis of variance. The current concentrations of V(V) and Cr(VI) in leaching solution were 23.70g/L and 1.52g/L, respectively. 99.6% of vanadium was extracted and separated from the aqueous solution by employing four-stage countercurrent extraction with annular centrifugal contactors (ACCs). The total contact/resident time of the two phases was 4.8 min, and the separation factor of V(V) and Cr(VI) was 273.9. The two metals in leaching solution can be separated primarily, and then 23.61g/L V(V) and 0.72g/L Cr(VI) in loaded organic phase can be further separated by the stripping. The NH 4 VO 3 with purity of 99.7% was obtained by two steps of separations and studied by the analyses of XRD, SEM and particle size distribution (PSD). The reactions of extraction and stripping in the separation processes were investigated in order to establish a firm conclusion. [ABSTRACT FROM AUTHOR]

The transformation and detoxification of halobenzoquinones (HBQs), a class of emerging disinfection byproducts (DBPs), was studied in the presence of amino acids (AAs). The reaction activity of three HBQs with AAs generally ranked as 2-chlorobenzoquinone (CBQ) < 2,6-dichlorobezoquinone (DCBQ) < tetrachloroquinone (TCBQ), consistent with their halogenation degree and the calculated electron affinity (EA) results. According to mass spectrometry and density functional theory (DFT) calculations, AAs can easily covalently incorporate into HBQs via nucleophilic addition (CBQ and DCBQ) or substitution (TCBQ) through C N C or C S C linkages. Hydroxylation, nucleophilic reaction and decarboxylation were proposed to be the three major reaction pathways for HBQs transformation with AAs. HBQs firstly underwent the spontaneous hydrolysis, resulting in OH-HBQs formation. Then, nucleophilic addition/substitution of AAs occurred on HBQs and OH-HBQs to produce AA-HBQs/AA-HBQs-OH adducts. These adducts were subsequently oxidized into their corresponding decarboxylated forms. Based on the results of Luminous bacterium Q67 acute toxicity test, the toxicity of HBQs solution greatly decreased with AAs presented. The toxicity change was well explained by the lowest unoccupied molecular orbital energy ( E LUMO ) of formed products. Notably, the step that AAs nucleophilic bonded with HBQs led to the highest rise of E LUMO , which should be the most effective pathway for HBQs detoxification. This study shows that binding with amino nitrogen compounds should be an important process for HBQs transformation and detoxification, which helps to better understand the fate of this typical DBP in surface water. [ABSTRACT FROM AUTHOR]

A novel nanofibers-covered hollow fiber membrane (N-HFM) with high porosity (83.5%) was prepared via employing electrospinning to deposit nanofibers onto a porous supporting tube. Electrospun nanofibers covered on a porous supporting tube serve as the outer layer of the N-HFM. The supporting tube fixed on the soft electrode serves as the collector as well as the inner layer of the N-HFM. When the feeding rate was 1 ml L −1 , it was possible to continuously fabricate N-HFM with a non-rotational collector. The prepared N-HFM was used for desalination by direct contact membrane distillation (DCMD), and a high distillate flux of 17 kg m −2 h −1 was obtained while the feed and permeate temperatures were fixed at 333 K and 293 K, respectively. It is expected that the novel hollow fiber membranes with high porosity fabricated by this continuous electrospinning technique may be attractive in various separation and purification processes. [ABSTRACT FROM AUTHOR]

Microbial electrolysis cells (MEC), coupled with sulfate-reducing bacteria (SRB), was used to degrade sulfate-rich wastewater that is deficient in electron donors. However, because of the impact of electric double layers (EDLs), salt crystals formed on the electrode, thereby potentially retarding the continuity of sulfate removal during the whole operation. Here, an improved MEC reactor using intermittent electric field was established. It works better in sulfate removal for a longer period, which was higher than the conventional MEC reactor by 2.18-fold after 10 days. Observation on the activity of lactic dehydrogenase (LDH) and ATP revealed that the formation of salt crystals on the electrode led to plasmatorrhexis. Conversely, improved reactor contributed to extracellular substances production and prevented the salt crystal formation, which was conducive to biofilm formation as further verified by detection through SEM. Electrochemical impedance spectroscopy tests showed that the cathodic microorganisms accelerated electron transfer whereas the salt crystals increased the charge transfer resistance. High-throughput sequencing analysis illustrated that improved reactor could maintain the competitiveness of SRB in the microbial community for a longer period. Moreover, the improved reactor resulted in high species diversity, thereby showing the significant resistance of the microorganisms to arduous environments. [ABSTRACT FROM AUTHOR]

In this study, the fouling of anion exchange membrane (AEM) in electrodialysis was investigated using sodium dodecyl sulfate (SDS) as a model foulant, and the effect of membrane cleaning on the properties of the fouled AEMs was examined further. Results showed that the severer fouling of AEM was caused by the higher concentration of SDS in the feed solution, and a dense SDS fouling layer was formed on the AEM surface, causing the obvious increase of electrical resistance and the deterioration of desalination performance. Electrochemical impedance spectroscopy (EIS) indicated the SDS fouling layer on the AEM could hinder, even restrict completely the transmembrane migration of the ions, especially at high concentration of SDS. The cleaning experiment showed the cleaning effect of ultra-pure water was similar to that of HCl solution, but was better than that of NaOH solution, in which most SDS on the fouled AEM could be removed effectively by cleaned in ultra-pure water. EIS of the fouled AEMs before and after cleaned indicated that the remaining SDS on the cleaned AEM had almost no influence on the transmembrane migration of the ions through AEM. [ABSTRACT FROM AUTHOR]

The effective V(V) and Cr(VI) separation is very difficult due to their similarity in physiochemical properties. In this research, almost completely separation of V(V) and Cr(VI) with primary amine N1923 was firstly demonstrated by employing multistage countercurrent extraction (MCE) with annular centrifugal contactors (ACCs). The optimum operation conditions of single-stage extraction with ACC were determined by systematic experiments, and best conditions of the rotor speed, the flow rate and the flow ratio of organic phase to aqueous phase were obtained. The loaded-organic phase can be reused for extraction process after stripping with ammonia/sodium hydroxide. Vanadium, in the leaching/aqueous solution with the initial pH of 6.1, was reached to extraction equilibrium by three-stage countercurrent extraction with ACCs. V(V) and Cr(VI) were separated through 21 stages of countercurrent extraction with ACCs. 95.1% of vanadium and almost none of chromium were extracted, with the separation factor approaching infinity. Through the mechanism of hydrogen bond association and different species of two metals in the leaching/aqueous solution, an in-depth analysis to correlate the results obtained and the chemical reactions with ACCs has been made in order to establish a firm conclusion with aim of the guidance in industrial application. [ABSTRACT FROM AUTHOR]

Microbial electrolysis cell (MEC) coupled with sulfate-reducing bacteria (SRB) was used to degrade sulfate-rich wastewater which was deficient in electron donors. Results confirmed that SRB could trigger vigorous synergy with an applied current. An applied electrical field of 1.5 mA (R1) resulted in the highest sulfate removal, which was 14.9% higher than that of the control reactor (R0). In addition, organic-substance consumption decreased with the increase of applied current. The concentration of lactic dehydrogenase (LDH), an indicator of cell rupture, increased by 3.59 times at 2.5 mA; that of ATP, an indicator of cell metabolism, sharply decreased under 2.5 and 3.5 mA. This finding indicated that high current led to plasmatorrhexis, low growth rate, and metabolic activity, subsequently reduced sulfate-reduction efficiency. Conversely, a proper current resulted in the enhancement of extracellular secretion, which was conducive to biofilm formation as further confirmed by detection through SEM. Electrochemical impedance spectroscopy (EIS) illustrated the SRB in the biofilm could accelerate the rate of direct electron transfer to cathode. Genus-level results further revealed that the dominant bacterium Desulfovibrio , an SRB, was richer in the cathode biofilm and R1, compared with R0. [ABSTRACT FROM AUTHOR]

We herein present systematic insights into the potential of a wide variety of dimension-structured nanocarbons in visible light-O 3 integrated process for metal-free water decontamination. Single-walled carbon nanotube (SWCNT), multi-walled carbon nanotube (MWCNT), reduced graphene oxide (rGO) and fullerene (C 60 ) demonstrated high activities in catalytic ozonation, while graphitic carbon nitride (g-C 3 N 4 ) and C 60 outshined in visible light-O 3 coupled process. The advantageous properties of nanocarbon materials in both catalytic ozonation and photocatalytic ozonation were acquired as further guidance for catalyst design. The effects of both liquid-phase and surface hydroxyl radicals ( OH) were determined by trapping experiments and in-situ electron paramagnetic resonance. The coupling coefficient of visible light and ozone on g-C 3 N 4 was 95.8, which was never achieved in the previous literature. The OH yield of Vis/O 3 /g-C 3 N 4 , interpreted from oxalic acid removal rate, was superior to those of O 3 /nanocarbon (MWCNT, rGO and C 60 ) and field-leading Vis/O 3 /metal oxides (WO 3 and TiO 2 ) systems. Further strategies on g-C 3 N 4 optimization were also proposed. This study contributes to the development of active metal-free nanocatalysts in photocatalytic ozonation for water treatment. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether human papillomavirus (HPV) DNA can be detected in the plasma of patients with HPV-positive oropharyngeal carcinoma (OPC) and to monitor its temporal change during radiotherapy. Methods and Materials: We used polymerase chain reaction to detect HPV DNA in the culture media of HPV-positive SCC90 and VU147T cells and the plasma of SCC90 and HeLa tumor-bearing mice, non-tumor-bearing controls, and those with HPV-negative tumors. We used real-time quantitative polymerase chain reaction to quantify the plasma HPV DNA in 40 HPV-positive OPC, 24 HPV-negative head-and-neck cancer patients and 10 non-cancer volunteers. The tumor HPV status was confirmed by p16INK4a staining and HPV16/18 polymerase chain reaction or HPV in situ hybridization. A total of 14 patients had serial plasma samples for HPV DNA quantification during radiotherapy. Results: HPV DNA was detectable in the plasma samples of SCC90- and HeLa-bearing mice but not in the controls. It was detected in 65% of the pretreatment plasma samples from HPV-positive OPC patients using E6/7 quantitative polymerase chain reaction. None of the HPV-negative head-and-neck cancer patients or non-cancer controls had detectable HPV DNA. The pretreatment plasma HPV DNA copy number correlated significantly with the nodal metabolic tumor volume (assessed using 18F-deoxyglucose positron emission tomography). The serial measurements in 14 patients showed a rapid decline in HPV DNA that had become undetectable at radiotherapy completion. In 3 patients, the HPV DNA level had increased to a discernable level at metastasis. Conclusions: Xenograft studies indicated that plasma HPV DNA is released from HPV-positive tumors. Circulating HPV DNA was detectable in most HPV-positive OPC patients. Thus, plasma HPV DNA might be a valuable tool for identifying relapse. [ABSTRACT FROM AUTHOR]

A novel composite modified membrane (PSS&PDA-M) was prepared by constructing polydopamine (PDA) self-polymerization modified layer covering electrodeposited poly (sodium 4-styrene sulfonate) (PSS) modified layer. The improvement on surface hydrophilicity and negative charge density of PSS&PDA-M mainly benefited from electrodeposited PSS modified layer. PDA self-polymerization modification layer not only improved the stability of the composite modified layer but also reduced the surface roughness of modified membrane. The results of desalination and antifouling experiments indicated that PSS&PDA-M had the best ability to inhibit fouling by sodium dodecyl sulfonate without affecting desalination performance. And it still had excellent antifouling performance after 120 h rinsing test. Moreover, the surface hydrophilicity and negative charge density of PSS&PDA-M with the best antifouling properties were slightly inferior to electrodeposited PSS modified AEM (ePSS-M). Therefore, enhancing the stability of modified layer was also crucial to improving the antifouling performance of AEM. [Display omitted] • PSS-modified layer can improve surface negative charge and hydrophilicity of AEM. • PDA-modified layer help to improve the smoothness and stability of modified layer. • PSS&PDA-M is more suitable for ED desalination of wastewater containing SDS. • Enhancing stability of modified AEM is crucial to improve antifouling ability. [ABSTRACT FROM AUTHOR]

The solubility of sodium tungstate dihydrate and sodium molybdate dihydrate in the (Na 2 MoO 4 + Na 2 WO 4 + Na 2 SO 4 + H 2 O) system was studied using experimental and calculated methods. The osmotic coefficient of sodium tungstate was fitted to calculate the thermodynamics parameters of (Na 2 WO 4 + H 2 O) system. The solubility of sodium tungstate dihydrate was determined using the dynamic method in Na 2 WO 4 –Na 2 SO 4 –H 2 O to establish the new model which can provide an estimate the solubility of sodium tungstate dihydrate in various conditions, combined with the data published, the solubility of sodium tungstate dihydrate and the sodium molybdate dihydrate in quaternary system of (Na 2 MoO 4 + Na 2 WO 4 + Na 2 SO 4 + H 2 O) was estimated using the parameters of the two ternary systems of (Na 2 WO 4 + Na 2 SO 4 + H 2 O) and (Na 2 MoO 4 + Na 2 SO 4 + H 2 O). The results show that the AARD is always small and the calculated value is basically consistent with the experimental values for the system studied. [ABSTRACT FROM AUTHOR]

Purpose: Xerostomia is a common radiation sequela, which has a negative impact on the quality of life of patients with head and neck cancer. Current treatment strategies offer only partial relief. Botulinum toxins (BTX) have been successfully used in treating a variety of radiation sequelae such as cystitis, proctitis, fibrosis, and facial pain. The purpose of this study was to evaluate the effect of BTX on radiation-induced salivary gland damage.Methods and Materials: We used a previously established model for murine salivary gland irradiation (IR). The submandibular glands (SMGs) of C5BL/6 mice (n=6/group) were injected with saline or BTX 72 hours before receiving 15 Gy of focal irradiation. Saliva flow was measured 3, 7, and 28 days after treatment. The SMGs were collected for immunohistochemistry, confocal microscopy, and Western blotting. A cytokine array consisting of 40 different mouse cytokines was used to evaluate cytokine profiles after radiation treatment.Results: Irradiated mice showed a 50% reduction in saliva flow after 3 days, whereas mice preinjected with BTX had 25% reduction in saliva flow (P<.05). Cell death detected by TUNEL staining was similar in SMG sections of both groups. However, neutrophil infiltrate, detected by myeloperoxidase staining, was 3-fold lower for the BTX treated mice. A cytokine array showed a 2-fold upregulation of LPS-induced chemokine (LIX/CXCL5) 3 days after IR. BTX pretreatment reduced LIX levels by 40%. At 4 weeks after IR, the saline (control) group showed a 40% reduction in basal SMG weight, compared with 20% in the BTX group. Histologically, BTX-pretreated glands showed relative preservation of acinar structures after radiation.Conclusions: These data suggest that BTX pretreatment ameliorates radiation-induced saliva dysfunction. Moreover, we demonstrate a novel role for CXCL5 in the acute phase of salivary gland damage after radiation. These results carry important clinical implications for the treatment of xerostomia in patients with head and neck cancer. [ABSTRACT FROM AUTHOR]