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Background: Fifth metatarsal base fracture (fifth MBF) and lateral collateral ankle ligament (LCAL) injury are mainly caused by plantar flexion and inversion of the foot. However, there is no relevant report on the incidence, injury type and treatment principle of the fifth MBF combined with an LCAL injury. Materials and methods: We retrospectively analyzed 61 patients with fifth MBF. After admission, patients were given the symptomatic treatment and underwent standard anteroposterior (AP), 30-degree oblique foot radiographs, ankle MR and/or ultrasonic examination. The type of surgery varied base on the individual patients (type of fracture with/without lateral collateral ankle ligament injury). Results: In 61 patients, there were 39 patients with LCAL injury. Among the 39 patients with LCAL injury, 24 patients with Grade I–II injury, 6 patients with Grade III injury, and 9 patients with avulsion fractures. There was no significant difference between the patients without LCAL injury and the patients with LCAL injury in terms of age (p = 0.67) and gender (p = 0.575). The incidence of fifth MBF with LCAL injury accounted for 63.93% of fifth metatarsal base fracture; the most common causes of injury included sprains and falls. The average fracture healing time was 8.3 (range, 6–12) weeks. For fifth MBF with displaced more than 2 mm, hook plate or lag screw was used for fixation; for complete rupture of LCAL, suture anchor was used to repairing the ligament; for partial LCAL injury, plaster was used for fixation after surgery; for avulsion fractures, cannulated screw or suture anchor was used for repair. None of the patients had complications such as delayed union, nonunion, and incision infection. Conclusion: Early diagnosis and appropriate treatment can obtain good therapeutic results in fifth MBF patients combined with LCAL injury. Moreover, defining a treatment plan for ligament injury is essential for reducing postoperative complications. This study provides a basis for epidemiology, diagnosis, and treatment of fifth MBF with LCAL injury. [ABSTRACT FROM AUTHOR]

Objective: The treatment of talar neck and/or body fractures is known to be difficult and challenging, with significant impact on the long‐term functional outcome for the patient. The optimal management, including the choice of surgical approaches and implants, are still under constant discussion. The purpose of the study was to investigate the clinical effects of lateral mini‐plate combined with medial lag screws for the treatment of complicated central talar fractures. Methods: The data of eight patients with complex central talus fractures treated between June 2019 and January 2021 were retrospectively analyzed. There were six males and two females, ranging in age from 15 to 66 years, with an average age of 37.4 years. There were three cases on the left and five cases on the right. All fractures were comminuted, including talar neck with talar body fracture in seven cases and talar body comminuted with subluxation of subtalar joint in one case. All patients were treated with the anteromedial combined anterolateral approach, lateral talar mini‐plate fixation and medial lag screw fixation. Fracture reduction quality, union time, and complications were recorded, and functional outcomes were evaluated using the American Orthopedic Foot & Ankle Society (AOFAS) scoring system. Results: The time from injury to surgery was 1–6 days, with an average of 3.38 days. The follow‐up period was 34–53 months (mean 44.88 months). All fractures healed with a mean healing time of 16.75 weeks (13–23 weeks). Anatomical reduction was observed in six cases and near in two cases. After operation, there was no loosening or breakage of implant, loss of fracture reduction, and irritation of skin and soft tissue by internal fixation. The average AOFAS score was 87.38 (48–100), with excellent five cases, good two cases and poor one case, and the excellent and good rate was 87.5%. Superficial skin necrosis in one surgical incision healed after dressing exchange. No deep infection occurred. One case (1/8, 12.5%) developed avascular necrosis of the talus without collapse. Posttraumatic arthritis was found in four cases (4/8, 50%). Conclusion: The utilization of lateral mini‐plates in combination with medial screws for treating complex central talar fractures results in satisfactory reduction and stable fixation, mitigating complications associated with poor reduction. However, due to the absence of an anatomical mini‐plate, pre‐contouring is necessary when applying the lateral plate. This demands a surgeon's thorough familiarity with the anatomical morphology of the talus and proficiency in surgical techniques. Posttraumatic arthritis is the most common complication of complex central talar fractures. [ABSTRACT FROM AUTHOR]

Glial cell-derived neurotrophic factor (GDNF) is reported to promote the survival of neurons and salivary gland regeneration after radiation damage. This study investigated the effect of GDNF on cell migration, growth, and response to radiation in preclinical models of head and neck squamous cell carcinoma (HNSCC) and correlated GDNF expression to treatment outcomes in HNSCC patients. Our ultimate goal is to determine whether systemic administration of GDNF at high dose is safe for the management of hyposalivation or xerostomia in HNSCC patients. Three HPV-positive and three HPV-negative cell lines were examined for cell migration, growth, and clonogenic survival in vitro and tumor growth assay in vivo. Immunohistochemical staining of GDNF, its receptors GFRα1 and its co-receptor RET was performed on two independent HNSCC tissue microarrays (TMA) and correlated to treatment outcomes. Results showed that GDNF only enhanced cell migration in two HPV-positive cells at supra-physiologic doses, but not in HPV-negative cells. GDNF did not increase cell survival in the tested cell lines post-irradiation. Likewise, GDNF treatment affected neither tumor growth in vitro nor response to radiation in xenografts in two HPV-positive and two HPV-negative HNSCC models. High stromal expression of GDNF protein was associated with worse overall survival in HPV-negative HNSCC on multivariate analysis in a combined cohort of patients from Stanford University (n = 82) and Washington University (n = 189); however, the association between GDNF gene expression and worse survival was not confirmed in a separate group of HPV-negative HNSCC patients identified from the Cancer Genome Atlas (TCGA) database. Based on these data, we do not believe that GNDF is a safe systemic treatment to prevent or treat xerostomia in HNSCC and a local delivery approach such as intraglandular injection needs to be explored. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Reduced graphene oxide and N-doped graphene were prepared by microwave irradiation. • Surface engineered graphene exhibited high catalytic ozonation activity. • Microwave reduction created more edging sites and graphitic nitrogen species. • Diverse reactive species, O 2 −, OH and 1O 2 , were possible for 4-nitrophenol degradation. Abstract N-doped graphene has demonstrated exceptional activities in versatile metal-free catalytic processes. In this study, reduced graphene oxide (rGO) and N-doped rGO were synthesized by a facile approach via microwave reduction with a low energy input and short reaction time. The activities of the derived carbocatalysts were evaluated by catalytic ozonation of 4-nitrophenol (4-NP). Compared with thermally annealed rGOs in argon atmosphere, microwave treated rGO demonstrated a better performance in catalytic oxidation, and N-doping would further improve the catalytic activity. It is discovered that microwave irradiation not only gave rise to more edging sites and dangling bonds in rGO, making higher catalytic potentials for ozone decomposition than that from thermal annealing, but also resulted in a higher concentration of N dopants. XPS studies revealed that more graphitic N species were incorporated into the carbon basal plane during the microwave reduction processes. The reactive oxygen species (ROS) in 4-NP oxidation were evaluated and identified by liquid-phase electron spin resonance (ESR) and radical scavenging tests, which indicated the generation of O 2 −, OH and 1O 2 for 4-NP degradation. This study provides a facile protocol for fabricating advanced nanocarbon materials for green oxidation and enables new insights in catalytic ozonation with state-of-the-art carbocatalysis. [ABSTRACT FROM AUTHOR]

Anode graphite was recovered from a spent lithium ion battery (LIB) and reutilized as a carbon precursor to obtain graphene-based materials. Characterization results revealed that impurities were removed from the obtained graphite powder by cleansing processes. The as-synthesized reduced graphene oxide (rGO) from the purified graphite (LIB-rGO) demonstrated excellent catalytic ozonation activity against organic pollutants removal. To probe potential catalytic active sites, LIB-rGOs with different defective levels but similar oxygen contents were synthesized. Catalytic ozonation tests revealed that a higher defective level resulted in a greater catalytic activity. Density functional theory (DFT) calculation further demonstrated that ozone molecules could spontaneously decompose into active oxygen species on graphene structural vacancies and edges, which consolidated the role of defective structure in catalytic ozonation activity. Meanwhile, we discovered the pollutant-structure-dependent behavior of dominant reactive oxygen species (ROS) with the aid of radical scavenging tests and electron paramagnetic resonance (EPR) spectra. For phenolic pollutants vulnerable to direct ozone attacking, superoxide radicals (O 2 − ) and singlet oxygen ( 1 O 2 ) were found to be responsible ROS, whereas hydroxyl radicals ( OH) were identified as the principle ROS for aliphatic organic pollutants destruction. This study not only put forward a possible way for reutilization of waste LIB anode, but also stepped further for investigating the catalytic ozonation mechanism towards the graphene-based materials including the active sites and the generation of ROS. [ABSTRACT FROM AUTHOR]

Source-specific potential health risk was proposed as an effective index for determining priority control sources of PM 2.5 -bound polycyclic aromatic hydrocarbons (PAHs) near an industrial park. However, industry-specific emission profiles were limited. In this study, 60 emission source samples from 13 industries and 139 p.m. 2.5 samples near an industrial park were collected from 2020 to 2021. The PAH profiles of 12 industrial emission sources were constructed to address the difficulty of source apportionment refined to industrial categories. A diagnostic ratio method and a positive matrix factorization method (PMF) were used to qualitatively and quantitatively determine the emission sources of 16 p.m. 2.5 -bound PAHs. The incremental lifetime carcinogenic risk (ILCR) of PAH inhalation exposure for the local population was attributed to sources by a PMF-ILCR model. The results show that the local PAH pollution seriously exceeded (86.3% sampling days) the standard (GB3095-2012). The concentration of PAHs was 33.6 ± 32.6 ng/m3 and showed a seasonal trend of "heating season > autumn > spring". There were five main sources of PM 2.5 -bound PAHs near the industrial park: heavy oil combustion (29.8%), coal and natural gas combustion (28.0%), vehicle emissions (19.9%), steel industry emissions (19.4%) and tar volatilization (2.9%). There is potential carcinogenic risk to both children (3.1 × 10−6) and adults (1.2 × 10−5). The mass contribution of each source to ambient PAHs is not equivalent to its contribution to potential health risk. The risks of PM 2.5 -bound PAHs almost all correspond to vehicle emissions (46.3%), heavy oil combustion (25.9%) and steel industrial sources (24.9%). [Display omitted] • PAH profiles for some typical industrial categories were constructed. • More representative potential sources of PM 2.5 -bound PAHs were identified. • Industry-related sources were refined in PAH source apportionment. • A PMF-ILCR model was used to assess the source-specific carcinogenic risks of PAHs. • Vehicle emissions corresponded to the highest carcinogenic risk of PAHs. [ABSTRACT FROM AUTHOR]

Three kinds of graphitic carbon nitride materials (bulk, porous and nanosheet g-C 3 N 4 ) were composited with a multiwall carbon nanotube (MWCNT) by a hydrothermal method, and the obtained b-C 3 N 4 /CNT, p-C 3 N 4 /CNT and n-C 3 N 4 /CNT materials were used in the electrodes for electro-peroxone process. It was found that the n-C 3 N 4 /CNT composite exhibited the highest efficiency in oxalate degradation, though it performed the worst in the oxygen-reduction reaction for H 2 O 2 production. The n-C 3 N 4 /CNT composite exhibited higher activity than CNT and other composites in catalytic ozonation experiments, due to the higher pyrrolic-N content modified on the CNT surface and higher surface area. It also has higher electron transfer ability, which benefited to the electro-reduction of both O 2 and O 3 . The result confirmed that catalytic ozonation process was an important means to enhance the degradation efficiency in the electro-peroxone process, besides peroxone process and O 3 -electrolysis. [ABSTRACT FROM AUTHOR]

Three simple structured nitrogen heterocyclic compounds (NHCs), namely indole (ID), benzopyrazole (BP) and benzotriazole (BT), were degraded via wet air oxidation (WAO) in an autoclave-type reactor. The elimination of target pollutants became significant only above 220 °C. The reactivity order of the three substrates was ID > BP > BT. The chemical oxygen demand (COD) removal levels were lower than 70%. Many partial oxidation intermediates were produced, as detected by electrospray ionization–mass spectrometry (ESI-MS). The presence of different anions, such as CO 3 2− , SO 4 2− , and PO 4 3− , had a detrimental effect on the removal performances. On the other hand, Cl − and NO 3 − had a beneficial effect on the WAO of the target pollutants. By combining quantum chemistry calculations and ESI-MS analysis, detailed degradation pathways of ID, BP, and BT could be proposed. It was concluded that ring breakage occurred on both the benzene and heterocyclic ring in the initial stage of WAO for all three substrates. [ABSTRACT FROM AUTHOR]

Catalytic ozonation is a highly effective method in wastewater treatment, and MnO 2 materials are widely recognized as active heterogeneous catalysts in this process. Many works reported the progress in active MnO 2 synthesis, but the active phase is rarely systematically studied. In this paper, all six phases of MnO 2 (α-, β-, δ-, γ-, λ- and ε-) were synthesized by facile methods. Their catalytic activities in ozonation of 4-nitrophenol (4-NP) were evaluated and correlated with the physicochemical properties obtained from X-ray Diffraction (XRD), transmission electron microscopy (TEM), physical adsorption and cyclic voltammetry (CV) analysis. α- MnO 2 was found to be the most active catalyst in 4-NP degradation at neutral pH. MnO 2 with low average oxidation state (AOS) showed stronger oxidation/reduction peaks in CV characterization, which benefited catalytic decomposition of ozone to generate active species. Superoxide radical was confirmed as the main oxidizing species, along with singlet oxygen and ozone molecule oxidation in bulk solution and little contribution of oxidation on the MnO 2 surface. Mn 2+ leaching happened during catalytic ozonation, but its catalytic role is negligible. This result may give rise to the preparation of new active MnO 2 catalysts. [ABSTRACT FROM AUTHOR]

Urban and suburban variations in PM 2.5 -bound PAH compositions, sources and their potential health risk in terms of quality-adjusted life year (QALY) loss were explored, taking Haidian and Fangshan as urban and suburban representatives in Beijing. The annual mean total concentration of 16 priority PAHs in Fangshan (26.95 ng/m3) was higher than that in Haidian (12.59 ng/m3). The concentration of PAHs was much higher during the heating season, with four-ring PAHs as the dominant species. The PMF-PSCF-CPF integrated source apportionment method identified the same three sources in both areas; however, the mass contribution of traffic emissions in Haidian (64.2%) was larger than that in Fangshan (54.7%), while the source of coal and natural gas combustion and the source of biomass combustion, petroleum volatilization and coke oven contributed less (26.4% and 9.3%) than those in Fangshan (32.1% and 13.2%). Potential risk contribution of vehicle emissions (Haidian: 2943.39 QALYs, 91.36%; Fangshan: 6360.58 QALYs, 83.25%) was much greater than its mass contribution because its emission contained more PAH species with high toxicity, such as BaP. QALY loss covers the content of mental health, integrates noncarcinogenic and carcinogenic effects, and can more comprehensively reflect the health loss of affected people, thus being a suitable indicator for determining priority control sources. [Display omitted] • PM 2.5 and PAH concentrations in suburban areas were higher than those in urban areas. • Four-ring PAHs were the major species in both urban and suburban areas. • Lung, laryngeal and nasopharyngeal cancers induced the most QALY loss, followed by COPD. • Benzo [a]pyrene contributed the most QALY loss, and naphthalene was the 2nd contributor. • Vehicle emissions contributed greater QALY loss in urban areas than in suburban areas. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nitration treatment enhanced the activity of activated carbon in catalytic ozonation. [•] The amination modification enhanced the activity of activated carbon in catalytic ozonation. [•] Acid oxygenated groups play a positive role in catalytic ozonation of oxalic acid. [•] This provides a new choice to promote the activity of activated carbon in catalytic ozonation. [Copyright &y& Elsevier]

The contents of arsenic (As) and cadmium (Cd) in the herbal medicine Panax notoginseng (PN) have attracted public attention for the safe use of PN. Species-specific safety limits for As and Cd based on health risk assessment are an effective measure for the safety of PN consumption. To decrease the uncertainty of risk assessment, the gastrointestinal bioaccessibilities of As and Cd in PN, the influence of pharmaceutical processes, and individual variations in the dosage and duration of PN preparations were introduced for probabilistic health risk estimation. The As and Cd concentrations in PN materials from three major medicinal material markets were in the ranges of 0.11–1.26 and 0.07–1.97 mg/kg, respectively. The gastrointestinal bioaccessibilities of As and Cd in PN determined by an in vitro experiment were 64.7 ± 3.9% and 84.1 ± 10.1%, respectively. There was almost no noncarcinogenic health risk; however, long-term consumption of the PN preparation may induce 3.53% of consumers to have carcinogenic risks exceeding 1 × 10−4. The safety limits of As and Cd in PN were then determined to be 1.5 and 3.6 mg/kg, respectively, based on this acceptable carcinogenic risk level. Furthermore, the bioaccumulation of As and Cd in PN and their impacts on pharmaceutical components were studied based on our investigation in 19 PN plantations in major production areas. The safety limits of As and Cd in the soils were thus determined to be 5.5 and 7.3 mg/kg, respectively. The establishment of species-specific safety limits for commonly used herbal medicine was proposed because current standards cannot ensure the safe usage of PN. [Display omitted] • Gastrointestinal bioaccessibility of As and Cd in PN was studied by an in vitro test. • The processing, dosage and duration of the clinical use of PN were investigated. • General standards for herbal medicine cannot ensure the safe use of PN. • A stricter As safety limit in PN was proposed for long-term use-induced cancer risk. • As and Cd safety limits in soil were determined to ensure the quality and safety of PN. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dramatic activity enhancement was observed over Fe-doped g-C 3 N 4. • Two-photoelectron reduction pathway was verified in Fe/g-C 3 N 4 Vis-O 3 system. • The different roles of single Fe atoms and nanoparticles was explored. • Fe(II)N x sites promoted the adsorption and reduction of O 2 rather than O 3. The identification of active sites and the establishment of structure-reactivity relationship at atomic scale is important for designing efficient catalysts and understanding the reaction mechanism. Here, single atom catalysts (SACs) of Fe anchored on g-C 3 N 4 were synthesized. The catalysts have larger surface area, more photo-generated electrons with stronger reduction ability and faster charge carrier migration than g-C 3 N 4 , thereby exhibited dramatically enhanced activity and stability in electron reduction of ozone (O 3) under visible light. However, lower catalytic performance was observed when Fe nanoparticles coexisted, which regulated more photoelectrons to reduce O 2 to OH via two or three-electron reduction pathways rather than one-electron reduction of O 3. Mössbauer spectrum and X-ray adsorption spectroscopy indicated that the presence of Fe nanoparticles led to higher proportion of Fe(II)N x , which played more significant role in the adsorption and reduction of O 2. The insight on the contribution of different Fe sites with well-defined local coordination structure is beneficial for rational design of efficient catalysts in photocatalytic ozonation. [ABSTRACT FROM AUTHOR]

Abstract: The roles of the emulsifiers in the crud formation during the long-term operation during the vanadium and chromium extraction were studied. The crud produced in the long-term operation of extraction was determined by GC–MS for organic phase and XPS for solid particles. The results indicate that the redox reaction occurs between Cr(VI) and organic compounds, and the reduction products of Cr(VI) induce more stable emulsion. Additionally, the roles of other types of solid particles and organic compounds confirmed before were carried out by thermodynamic calculation and experiments combined with discussion. Three-dimensional network structure of silica and precipitation of various cations act as the major incentives to stimulate the emulsion. Whereafter, crystallization of sodium sulfate and the reduction of Cr(VI) take place at the surface of emulsion droplet, and the organic compounds are prone to be adsorbed by these fine solids which subsequently consolidate the newly formed surface of droplet. The interactions between emulsion droplets were calculated according to the extended DLVO theory. The comprehensive stabilization mechanisms were also proposed, including the composite interfacial film mechanism, the steric hindrance mechanism and the double electric layer mechanism. [Copyright &y& Elsevier]

Abstract: The stability of the interfacial crud produced during the extraction and separation of vanadium and chromium was studied in this paper. Thermodynamic stability, particle size distribution, setting time and clarifying curve of the emulsion droplet were investigated. From the results, the percentage of the crud produced decreases with the increasing setting time and after 30min it shows less change. The coalescence rate is relatively smaller than the rising rate, and the phase separation time is determined by the coalescence behavior of the droplet. The crud is considered to have thermodynamic instability, kinetic stability. The demulsifying mechanism was also put forward. New extraction system using n-hexane instead of kerosene as diluent with larger surface energy can prevent the emulsion formation. [Copyright &y& Elsevier]

Sulfate reducing bacteria (SRB) is identified as the primary organisms responsible for the treatment of heavy metal wastewater. However, most heavy metals can inhibit the growth of SRB during heavy metal treatment processes. Sulfide is a metabolic product of SRB and it can precipitate or reduce heavy metals. This study focused on the effects of sulfide on SRB resistance to Cu(II), Hg(I) and Cr(VI) toxicity. First, we considered the existence style of various heavy metals with and without sulfide addition by sequential extraction experiments. Second, the particle size distribution was evaluated and the cell structure during the metabolism of a SRB culture, containing different heavy metals, was analyzed by particle size distribution and TEM analyses. Third, the evolution of sulfate under the influence of different concentrations of heavy metals with and without sulfide addition was investigated to evaluate SRB activity. The results indicated that sulfide played an important role in alleviating and even eliminating the toxicity of Cu(II), Hg(II) and Cr(VI). We also discuss the mechanism of sulfide on SRB resistance to Cu(II), Hg(I) and Cr(VI) toxicity. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the interfacial crud produced during the extraction of vanadium and chromium by primary amine N1923 was investigated from the leaching solution containing heavy metals. Effect of pH values of the leaching solution on the percentage of the crud produced and the emulsion type of the crud were studied. X-Ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffraction (XRD) and Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) have been employed for the physiochemical characterizations of the crud. Our results indicate that the percentage of the crud produced is greatly affected by the pH value of the real leaching solution, and the crud is more stable in the acidic solution. The crud is an oil-in-water emulsion with many fine solid particles in the water phase. The particles, which are from the real leaching solution, have been proved to be the main cause for the crud formation. Particles in the cruds are normally composed of a large number of the crystals of Na2SO4, a few SiO2 and oxides or hydroxids of Fe and Al. However, component proportions of the solids are dependent on the pH values. Possible mechanism of the crud formation is put forward. The solids present in the real leaching solution exert a stabilizing effect on the emulsion, based on which Na2SO4 crystallizes at the interface of the emulsion. Furthermore, the Na2SO4 crystals strengthen the stability of the emulsion, and thereafter the interfacial crud forms. Three effective methods to prevent the crud formation are proposed, i.e. clearing the real leaching solution by membrane filtration, increasing of the amount of the modifier, and applying of hexane as the diluent. [Copyright &y& Elsevier]

With the rapid development of the lithium-ion battery (LIB) industry, the demand for core valuable elements in LIB has increased dramatically. A safe supply of corresponding metals is crucial to ensure the industry's sustainability. However, quantitative evaluation to reveal the supply risk including criticality of LIBs in China is still not available. In this regard, criticality analysis was carried out to identify the importance of a specific metal in the current LIBs supply chain of raw materials. Subsequently, a comprehensive methodology to evaluate supply sustainability is established in this research by considering the combined effects of material supply, economic fluctuations, and technology innovation in the time frame from 2015 to 2030. An integrated index called Chinese supply resilience is introduced, indicating that a low Chinese supply resilience has a high possibility of supply shortage of the corresponding metal while a high resilience level represents minor supply risk. The results show that insufficient material supply has already induced a severe shortage for lithium (Li) and cobalt (Co). Specifically, Chinese supply resilience of lithium moves from the threshold to the low resilience zone, whereas that for cobalt remains in the low area, both implying a high risk of supply shortage. Furthermore, three appropriate mitigation measures, that is, recycling of spent LIBs, substitution of raw materials, and an increase in domestic raw materials production are considered. Recycling demonstrates the most effective solution to alleviate the potential supply risk of corresponding materials. With this research, it may promote management efficiency on end-of-life LIBs for policy makers. Image 1 • The index of Chinese supply resilience is used to evaluate supply risk of materials. • Supply resilience for Li moves from the threshold to the low-resilience zone. • Supply resilience for Co remains in the low-resilience zone. • Effect of material supply, economy and technology innovation is analyzed. • Scenario analysis considering recycling, substitution and production is conducted. [ABSTRACT FROM AUTHOR]

• Persulfate combined wet air oxidation (PWAO) is proposed to deep remove benzothiazole. • OH is firstly detected by electron paramagnetic resonance in wet air oxidation process. • OH plays a very important role in the PWAO process. • High COD removal is achieved with a large amount of microsphere polymers recycling. • The PWAO process has a lower operating cost than WAO in COD removal. Wet air oxidation (WAO) has an obvious advantage in treating wastewater with high concentration of organics, but harsh reaction conditions are required and the treatment efficiency has not reached a satisfactory level. Herein, we developed a low dosage of persulfate promoted WAO process (PWAO) to remove a model heterocyclic pollutant benzothiazole (BTH). The addition of persulfate remarkably enhanced the elimination of benzothiazole (BTH) and COD from water via degradation and polymerization. Under optimized operation condition (with 11.1 mM K 2 S 2 O 8 addition into WAO), about 65.0% of BTH converted into microsphere polymers and more than 94.6% COD was eliminated from water after polymers separation. Electron paramagnetic resonance (EPR) analysis and quenching experiments revealed that OH was effectively generated in a wide range of reaction temperature and it played the key role in BTH degradation and polymerization, while SO 4 − was detected at low temperature for its fast decomposition at high temperature. Quantum chemical calculation together with ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS) analysis confirmed that the degradation and polymerization of BTH mainly started from the heterocyclic ring, followed by further oxidation or polymerization. Comparing with normal WAO process, the PWAO technology had an advantage in lower operating cost in removing per unit COD and carbon resource recycle, which indicates a promising prospect in treating wastewater with high concentration of heterocyclic compounds. [ABSTRACT FROM AUTHOR]

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]

• 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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

The solubility of Na 2 MoO 4 ·2H 2 O in (Na + + MoO 4 2− + SO 4 2− ) system was carried out using a dynamic method within the temperature range from 293.15 K to 343.15 K. The new model was established via regression of the published and the determined values to predict the solubility. From the results, the solubility of sodium molybdate increases with the temperature increase, however, it decreases with the increasing concentration of sodium sulfate. The Pitzer parameters and the solubility product constant of sodium sulfate and sodium molybdate in aqueous solution were obtained using the literature data. The solubilities of the sodium molybdate in the sodium sulfate solution as well as the thermodynamic parameters were calculated based on the experimental values obtained. The new model was also applied to estimate the solubility of the sodium molybdate under various conditions. The calculated values agree well with the experiment results. [ABSTRACT FROM AUTHOR]

The key standpoint favors the role of doped metal ions as electron traps in enhancing surface-charge separation during TiO 2 photocatalysis. Besides that, this study demonstrated two disparate impacts of metal ion doping on reactive species generation during TiO 2 photocatalysis. Ag + and Cu 2+ outperformed other dopants in photooxidation of oxalic acid (OA), while further increasing their doping amount from the optimum value produced a negligible impact on the photocatalytic performance. This implied other dominant roles of doped metal ions other than electron captors, because an excessive amount of traps can serve as charge-recombination centers and largely decrease the photocatalytic activity. N 2 purging and NaF (a scavenger for surface-radicals) markedly reduced the mineralization rate after Ag + doping, verifying the significance of dissolved oxygen (DO) in reactive species generation upon TiO 2 surface. Non- OH reactive oxygen species (ROS) were found to account for 75% in OA mineralization, attributed to enhanced DO adsorption towards TiO 2 surface by Ag + doping. However, Cu 2+ doping could facilitate the oxidation by h vb + plus OH ads , which took as dominant a part as 53%. Ag + -Cu 2+ co-doping integrated these two positive sides and more inclined to the role of Ag + . Correspondingly, surface oxidation dominated whereas liquid-phase oxidation weakened. [ABSTRACT FROM AUTHOR]

Two series of α-MnO 2 materials were prepared via a similar method with surfactant cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfate (SDBS). The surfactants work both as shape directing agent and reduction initiator. The α-MnO 2 synthesized with 0.2 M of CTAB showed a mesoporous structure with high surface area of 387.7 m 2 /g. It is very active in catalytic ozonation of 4-nitrophenol (4-NP) and total organic carbon removal, with higher catalytic stability than commercial MnO 2 . Using tert -butanol and p -benzoquinone as scavengers of different oxidative species, we found that superoxide radicals, rather than hydroxyl radicals, were mainly responsible for the degradation of 4-NP. [ABSTRACT FROM AUTHOR]

Photocatalytic ozonation offers a potential approach for highly efficient organic degradation by in-situ generation of reactive •OH via electron reduction of ozone. Herein, we synthesized a Mn single atom photocatalyst for promoting the •OH generation from O 3 activation under visible light irradiation. Theoretical calculation and experimental studies reveal that Mn single atoms on carbon nitride significantly promote the excitation and transfer of photo-generated electrons, making charge carriers enriched around MnN 4 sites and shortening their migration path to participate in surface reactions. Meanwhile, Mn single atoms serve as adsorption and catalytic sites for O 3 , favoring a fast one-electron-reduction reaction kinetics. More importantly, the trade-off between the number of available electrons and active sites in photocatalytic performance was observed from regulating the density of Mn single atoms. This work offers an intriguing regulation strategy for enriching surface charges on single atom catalyst interface toward efficient •OH production and removal of aqueous organics. [Display omitted] • Mn single atom catalysts demonstrate high performance in photocatalytic ozonation. • The anchored Mn single atoms enrich photo charge carriers for promoting O 3 adsorption. • One-electron reduction path ensures efficient O 3 activation to hydroxyl radicals. • A higher Mn single atom density favors higher photocatalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The influences of 31 nucleophiles on the removal of dichlorobenzoquinones (DCBQs) was studied. • Degradation kinetics, pathways and toxicity evolution of DCBQs were characterized. • Fast removal and detoxification of DCBQs was achieved with the presence of thiol compounds. • Role of amino acids in promoting DCBQs hydrolyzation was revealed. • Relationships among nucleophilic structures, transformation pathways and products were found. Halobenzoquinones (HBQs), a metabolism of pentachlorophenol, arouse increasing concern for their high toxicity. This paper systematically studied the influences of 31 extracellular nucleophiles on the removal of dichlorobenzoquinones (DCBQs). The results showed that at pH 6.0–8.0, the transformation of DCBQs followed a pattern of pseudo first-order reaction. With the presence of different thiol compound (ratio 1:1), the apparent rate constant of 25DCBQ and 26DCBQ was between 0.028 and 0.204 min−1 and 0.061–0.156 min−1, respectively, which was 6.6–48.3 times faster than direct hydrolysis and 1.9–23.4 times of that with histidine, a typical amino acid. This was attributed to the different transformation pathways of DCBQs with thiol or amino groups. According to the MS spectrum and transition state theory, thiol compounds was stably incorporated into DCBQs via Michael addition or substitution, which also decreased the oxidative stress of DCBQs by 35.5–86.4% and cytotoxicity of hydrolyzed DCBQ by 44.9–100%, respectively. Conversely, amino acids promoted the hydrolysis of DCBQs by forming unstable AA-DCBQ intermediates that can be further hydrolyzed to OH-DCBQs, leading to an increased selectivity of OH-DCBQs, and increased the oxidative stress of 25DCBQs by 0.2–31.2% and cytotoxicity of hydrolyzed 25DCBQ by 42.0–52.7%. Such difference was inherently related to the nucleophilicity of different atoms. Moreover, it was revealed that the maximum condensed local nucleophilicity index of nucleophiles (N k, max) can joint describe the relationship among nucleophilic structures, transformation pathways and toxicity of DCBQs. This paper provided a comprehensive perspective on the fast removal and detoxification of HBQs in extracellular environment. [ABSTRACT FROM AUTHOR]

The wastewater usually contains low-concentration organic pollutants and some inorganic salts after biological treatment. In the present work, the possibility of simultaneous removal of them by combining electrochemical oxidation and electrosorption was investigated. Phenol and sodium chloride were chosen as representative of organic pollutants and inorganic salts and a pair of activated carbon plate electrodes were used as anode and cathode. Some important working conditions such as oxygen concentration, applied potential and temperature were evaluated to reach both efficient phenol removal and desalination. Under optimized 2.0 V of applied potential, 38 °C of temperature, and 500 mL min −1 of oxygen flow, over 90% of phenol, 60% of TOC and 20% of salinity were removed during 300 min of electrolysis time. Phenol was removed by both adsorption and electrochemical oxidation, which may proceed directly or indirectly by chlorine and hypochlorite oxidation. Chlorophenols were detected as degradation intermediates, but they were finally transformed to carboxylic acids. Desalination was possibly attributed to electrosorption of ions in the pores of activated carbon electrodes. The charging/regeneration cycling experiment showed good stability of the electrodes. This provides a new strategy for wastewater treatment and recycling. [ABSTRACT FROM AUTHOR]

Heterogeneous photocatalysis and ozonation are robust advanced oxidation processes for eliminating organic contaminants in wastewater. The combination of these two methods is carried out in order to enhance the overall mineralization of refractory organics. An apparent synergism between heterogeneous photocatalysis and ozonation has been demonstrated in many literatures, which gives rise to an improvement of total organic carbon removal. The present overview dissects the heterogeneous catalysts and the influences of different operational parameters, followed by the discussion on the kinetics, mechanism, economic feasibility and future trends of this integrated technology. The enhanced oxidation rate mainly results from a large amount of hydroxyl radicals generated from a synergistically induced decomposition of dissolved ozone, besides superoxide ion radicals and the photo-induced holes. Six reaction pathways possibly exist for the generation of hydroxyl radicals in the reaction mechanism of heterogeneous photocatalytic ozonation. [ABSTRACT FROM AUTHOR]