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The efficient recovery of nickel from chloride systems has long presented a challenge in the field. While solvent extraction is a viable approach, conventional extractants have been associated with drawbacks such as a high requirement for chloride ions and substantial consumption of acids and alkalis. In response to these challenges, this investigation developed and synthesized a novel thiazole-based extractant, N, N-Bis(4-thiazolylmethyl)octylamine (NNBT), tailored for the selective extraction of nickel from chloride systems. Findings from the study indicate that the nitrogen atom situated on the benzylamine framework within NNBT can interact synergistically with the chelating thiazole ring, facilitating effective nickel extraction and notably reducing the need for chloride ions. Furthermore, the extractant can be regenerated using deionized water, thereby obviating the necessity for additional consumption of acids and alkalis. Following the validation of NNBT as an environmentally sustainable and efficient nickel extractant within the chloride ion system, it was successfully employed to selectively and effectively extract nickel from the nickel-aluminum slag of spent HDP catalyst. The extracted nickel and aluminum were subsequently processed into electroplated nickel chloride and polyaluminum chloride, respectively, meeting the national standards of China. These outcomes underscore the eco-friendliness and promise of NNBT for nickel extraction from chloride systems. [Display omitted] • A more stable chelating extractant for nickel was designed and synthesized. • The nickel extraction mechanism in the chlorination system was revealed. • Efficient utilization of nickel-aluminum slag from spent catalysts. • Clean water achieves the nickel stripping and extractant regeneration. [ABSTRACT FROM AUTHOR]

The complex of heavy metals and organic acids leads to high difficulty in heavy metals separation by traditional technologies. Meanwhile, alkaline precipitation commonly used in industry causes the great consumption of resources and extra pollution. Herein, the effective decomplexation of Cu(Ⅱ)-EDTA and synchronous recycling of Cu2+ were realized by contact-electro-catalysis (CEC) coupled with capacitive deionization (CDI) innovatively. In particular, fluorinated ethylene propylene (FEP) as dielectric powders could generate reactive oxygen species under ultrasonic stimulation, realizing continuous deaminization and decarboxylation of Cu(Ⅱ)-EDTA and accelerating the totally breakage of Cu-O and Cu-N bonds. Additionally, the degradation pathway and intermediates evolution of Cu(Ⅱ)-EDTA were investigated using various characterization methods. It was confirmed that decarboxylation predominantly governed the degradation process of Cu(Ⅱ)-EDTA in CEC. During the course of treatment, the degradation ratio of Cu(Ⅱ)-EDTA reached 86.4 % within 150 min. Impressively, this strategy had satisfactory applicability to other metal combinations and excellent cycle stability. Subsequently, the released Cu ions were captured by CuSe cathode electrode through CDI. This research elucidated the degradation mechanism of persistent organic pollutant during CEC, and provided a novel approach for efficiently treating industrial wastewater containing metal complexes and advancing the exploitation and utilization of new technologies for metal recovery. [Display omitted] • The reactive oxygen species were generated in CEC without extra oxidants. • FEP as dielectric powders could effectively degrade Cu(Ⅱ)-EDTA in CEC. • CEC coupled CDI could degrade Cu(Ⅱ)-EDTA and directly capture Cu2+. • The decomplexation of Cu(Ⅱ)-EDTA in CEC was dominated by decarboxylation. [ABSTRACT FROM AUTHOR]

Fluoride (F−) pollution in groundwater is an important environmental issue and capacitive deionization (CDI) holds promise for defluorination at moderate concentrations (e.g., 200 −1000 mg L−1). However, existing electrodes suffer from the overlap of electrical-double-layer (EDL) and severe co-ion effects at low (e.g., <200 mg L−1) and high sodium fluoride (NaF) concentrations (e.g., >1000 mg L−1), respectively, exhibiting poor salt adsorption capacity (SAC). Hence, a three-layer structured electrode, "membrane/carbon nanotube (CNT)/activated carbon (AC)" (CNT-MCE), was prepared through electrospinning CNT onto AC, followed by a polymer membrane coating. Compared to AC and membrane coated electrode, CNT-MCE with mesopore-dominated structure prevented EDL overlap, achieving a higher SAC of 40.8 mg g−1 at 100 mg L−1 NaF. At 1500 mg L−1 NaF, the positively charged CNT-MCE exhibited an improved SAC of 58.8 mg g−1 by inhibiting co-ion effects. Meanwhile, CNT-MCE consistently demonstrated superb SACs at 200 − 800 mg L−1 NaF and maintained excellent stability over a wide concentration gradient by inhibiting severe oxidation. Notably, CNT-MCE successfully decreased the F− concentration in simulated groundwater from 3.4 to 1.1 mg L−1. Overall, our work provides an efficient strategy of electrode design to broaden the applicability of CDI for groundwater defluorination over a wide concentration gradient. [Display omitted] • Three-layer structured membrane coating electrode was prepared for F- removal. • High F- adsorption capacities were obtained over the wide concentration gradient. • Mesopore-dominated structure overcame the overlapping of electrical double layer. • Positively charged polymer membrane inhibited the serious co-ion repulsion effect. [ABSTRACT FROM AUTHOR]

As an eco-friendly technique with the superior adsorption performance, electroadsorption has shown great potential for application in uranium (U(VI)) recovery in recent years. However, the electrodes used in the electrosorption generally suffer the adsorbent to be loaded on the conductors, which greatly limited the adsorption performance of the electrodes for uranyl ions. In present study, a flexible self-supporting Na 3 MnTi(PO 4) 3 @C fibers (NMTP@C fibers) electrode material was rationally designed and prepared by electrostatic spinning method and annealing technique, and its ability to capture U(VI) efficiently was preliminarily demonstrated by batch adsorption and electro sorption. The plentiful phosphate groups provide sufficient active sites for adsorption, while the axially continuous electron conduction and radially short-range ion transport give NMTP@C fibers fast charge/ion transport capability. The NMTP@C fiber can remove 99% of 5 ppm U(VI) in seawater by electro absorption within 1 h. After several cycles of adsorption under seawater conditions, the adsorbent can still maintain a stable adsorption capacity. The adsorption mechanism of NMTP@C nanofibers for U(VI) was investigated by XPS, FT-IR, Raman, SEM-EDS, and XRD, which was electrostatic interactions and surface complexation. These results suggest that NMTP@C fibers are promising high-capacity adsorbents for efficient and selective capture of U(VI) from seawater. [Display omitted] • Na 3 MnTi(PO 4) 3 @C was rationally designed as flexible self-supporting electrode. • Na 3 MnTi(PO 4) 3 @C is ecofriendly, low cost and low energy consumption. • Na 3 MnTi(PO 4) 3 @C exhibit high selectivity and uptake capacity for U(VI) with remarkable reusability. • U(VI) adsorption mechanism involves electrostatic interactions and surface complexation. [ABSTRACT FROM AUTHOR]

Fluorinated compounds are a class of organic substances resistant to degradation. Although zero-valent iron (Fe0) has a promising reducing capability, it still fails to degrade fluorine-containing antibiotics (i.e., florfenicol) efficiently. In this study, we applied a simple one-pot pyrolytic approach to synthesize nitrogen-doped biochar supported Fe0 and zero-valent copper (Cu0) composite (Fe/Cu@NBC) and investigated its performance on florfenicol removal. The results clearly showed that approximately 91.4% of florfenicol in the deionized water was removed by Fe/Cu@NBC within 8 h. As the reaction time was extended to 15 d, the total degradation rate of florfenicol reached 96.6%, in which the defluorination and dechlorination rates were 73.2% and 82.1%, respectively. Both experimental results and density functional theory calculation suggested that ∙OH and ·O 2 − triggered β-fluorine elimination, resulting in defluorination prior to dechlorination. This new finding was distinct from previous viewpoints that defluorination was more difficult to occur than dechlorination. Fe/Cu@NBC also had a favorable performance for removal of florfenicol in surface water. This study provides a new insight into the degradation mechanism and pathway of florfenicol removal in the Fe/Cu@NBC system, which can be a promising alternative for remediation of fluorinated organic compounds in the environment. [Display omitted] • Fe/Cu@NBC was successfully synthesized with a simple one-pot pyrolytic approach. • An efficient florfenicol removal as high as 91.4% was achieved within 8 h. • ·O 2 − played a dominant role in the defluorination of florfenicol via β-elimination reaction. • Florfenicol degradation pathway followed firstly defluorination and subsequent dechlorination. [ABSTRACT FROM AUTHOR]

In modern industry, selective extraction and recovery of Cu from strongly acidic electroplating effluent are crucial to reduce carbon emissions, alleviate resource scarcity, and mitigate water pollution, yielding considerable economic and environmental benefits. This study proposed a high-efficiency CuSe electrode to selectively remove Cu from electroplating effluent via hybrid capacitive deionization (HCDI). The potential of this electrode was thoroughly evaluated to assess its effectiveness. The CuSe electrode exhibited superior deionization performance in terms of Cu adsorption capacity, selectivity, and applicability in various water matrices. Specifically, under strong acid conditions (1 M H+), the CuSe electrode maintained an optimal adsorption capacity of 357.36 mg g−1 toward Cu2+. In systems containing salt ions, heavy metals, and actual electroplating wastewater, the CuSe electrode achieved a remarkable removal efficiency of up to 90% for Cu2+ with a high distribution coefficient K d. Notably, the capacitive deionization (CDI) system demonstrated the simultaneous removal of Cu-EDTA. The removal mechanism was further revealed using ex-situ X-ray diffraction and X-ray photoelectron spectroscopy analyses. Overall, this study presents a practical approach that extends the capabilities of CDI platforms for effectively removing and recovering Cu from acidic electroplating effluent. [Display omitted] • CuSe materials were prepared by a facile hydrothermal method. • CuSe electrodes were used for the first time in the field of CDI. • CuSe exhibited a higher adsorption capacity and excellent selectivity toward Cu2+. • The practical potential for application in real water matrices has been verified. [ABSTRACT FROM AUTHOR]

• Tailor-made Thin film Poly(piperizinamide) Composite membrane including copper moiety. • Selectivity in bivalent- monovalent salt depends on the sequence of reagents during interfacial polymerization. • Separation behavior of mono and disaccharides for all the membranes. • Separation behavior of Hexaconazole in different water matrices. • Development of antibacterial property related to E. Coli and Bacillus subtilis. Thin film Poly(piperazine-amide) composite membranes using sequential interfacial polymerization with tuning by Cu2+ have brought significant findings in it. The hydrophobicity is relatively enhanced for the copper containing membranes. The membrane in which copper solution is applied prior to piperizine (Memb-III) exhibits higher hydrophobicity where as membrane (Memb-II) in which copper solution is applied following piperizine, possesses higher roughness compared to other two. Filtration experiments in terms of salts, mono/disaccharides and hexaconazole indicate that modified membranes are of different behaviours according to their sequence of preparative methods. Memb-III has shown lower SO 4 =/Cl− selectivity compared to Memb-II (i.e. 3.92), though they are in different range. The unmodified membrane (Memb-I) exhibits SO 4 =/Cl− selectivity 3.23 is in the same scale of Memb-III (2.27). Memb-III exhibits higher hexaconazole separation (91.5%) compared to Memb-II (i.e. 53.9%). The flux decline follows the order: field water > tap water > deionized water. The copper incorporated membrane (Memb-II) has shown a low flux decline compared to Memb-III as well as Memb-I. The antibacterial properties towards E. Coli and Bacillus subtilis are well reflected. The copper containing membranes have promising antibacterial properties and follows the order Memb-II > Memb-III > Memb-I. [ABSTRACT FROM AUTHOR]

Highlights • The combined freeze-thaw and soil washing method for remediation of heavy metal contaminated clay soils is proposed. • The method can improve removal efficiency due to repeated freeze-thaw destroying soil particle structure. • The washing efficiency can be guaranteed at low liquid/soil ratios through combined freeze-thaw and soil washing. • To provide basis for remediating heavy metal contaminated soils in seasonal frozen area by using natural cold energy. Abstract To improve the washing efficiency for low-permeability clay, the method of freeze-thaw synergistic chemical washing was put forward to study the cadmium (Cd)-and lead (Pb)- real-site contaminated soils as the research object and ethylene diaminete traacetic acid (EDTA) was selected as the eluent to conduct a soil column washing test of heavy metal-contaminated clay soil. Results show that repeated freeze-thaw of soil can destroy the original structure of soil particles, help the eluent fully interact with pollutants, and thus improve washing efficiency. Cd was showed the best removal effect after supplying 0.1 mol/L EDTA twice and deionized water thrice by freeze-thaw and washing, and the removal rate reached 88.07%. Pb was also showed the better removal effect after three times of 0.1 mol/L EDTA and four times of deionized water through freeze-thaw and washing, and the removal rate reached 37.78%. Combined freeze-thaw and chemical washing can effectively remove the reducible and residual fractions of Cd and Pb in the clay soils. Moreover, freeze-thaw synergistic chemical washing can remove Cd and Pb at low liquid/soil ratios. The conclusions obtained in the study are of important theoretical value and technical support for the similar engineering. [ABSTRACT FROM AUTHOR]

Selective capture of radioactive 99TcO 4 - from highly alkaline nuclear waste is highly desirable for environmental remediation and waste disposal. However, the combined features of adsorbents with excellent chemical stability and high capture selectivity for 99TcO 4 - have not yet been achieved. Herein, we report an ultra-stable 3D pyridinium salt-based polymeric network (TMP-TBPM) nanotrap with remarkable radiation, acid and base stability for selective capture of ReO 4 - via hydrophobic engineering and steric hindrance, a non-radioactive surrogate of 99TcO 4 -. The batch capture experiments show that TMP-TBPM has high capture capacity (918.7 mg g−1) and fast sorption kinetics (94.3 % removal in 2 min), which can be attributed to the high density of pyridinium salt-based units on the highly accessible pore channels of 3D interconnected low-density skeleton. In addition, the introduction of abundant alkyl and tetraphenylmethane units into the 3D framework not only greatly enhanced the hydrophobicity and stability of TMP-TBPM, but also significantly improved the affinity toward 99TcO 4 -/ReO 4 -, enabling reversible and selective capture of 99TcO 4 -/ReO 4 - even under highly alkaline conditions. This study exhibits the great potential of 3D pyridinium salt-based polymeric network nanotrap for 99TcO 4 -/ReO 4 - capture from highly alkaline nuclear waste, providing a new strategy to construct high-performance cationic polymeric sorbents for radioactive wastewater treatment. [Display omitted] • Robust 3D pyridinium salt-based polymeric network for selective capture of ReO 4 −. • The first example of 3D pyridinium salt-based polymeric network for ReO 4 - capture. • TMP-TBPM has excellent capture performance and high selectivity for 99TcO 4 -/ReO 4 -. • TMP-TBPM can selectively and reversibly capture 99TcO 4 -/ReO 4 - under alkaline conditions. [ABSTRACT FROM AUTHOR]

In the present work, a novel, floral-like, magnetic sodalite microsphere (SODM) was synthesized in situ by using fly ash (FA) and metakaolin (MK) as raw materials and was used to remove Cd(II) from water. Its magnetism can solve the problems of adsorbent recovery and possible secondary pollution. During the static adsorption, SODM shows a maximum adsorption capacity of 245.17 mg/g. The adsorption of Cd(II) on the SODM surface is spontaneous, exothermic, and physicochemical adsorption, which was evaluated by thermodynamics, kinetics, and isotherm studies. During dynamic adsorption, SODM shows a maximum adsorption capacity of 342.74 mg/g in the simulated solution prepared by the deionized water, compared to 215.88 mg/g in the simulated solution prepared using Xiangsi Lake water from Guangxi Minzu University. At 0.5 g SODM dosage in the dynamic adsorption, the adsorption capacity could rise to 632.81 mg/g. These results demonstrated the excellent Cd (II) adsorption performance of the SODM. The adsorption of cadmium on the SODM surface includes the synergistic effects of electrostatic attraction, ion exchange, and surface coordination reaction. Besides, the SODM shows good regeneration performance in both the deionized water and Xiangsi Lake water. The present study explores SODM as an adsorbent for the Cd (II) removal from wastewater and unbolts the industrial applicability of the SODM in the field of wastewater purification. [Display omitted] • The sodalite zeolite synthesized in situ by adjusting the content ratio of fly ash to metakaolin. • The SODM which contained low-cost raw materials exhibits magnetism and a flower-like morphology. • The adsorption capacities were 245.17 and 342.72～632.81 mg/g in the static, dynamic adsorption respectively. • The adsorption mechanisms included ion exchange, electrostatic interaction and surface coordination. • After 5 cycles, SODM has good regeneration performance in both lake water and deionized water. [ABSTRACT FROM AUTHOR]

Capacitive deionization (CDI) is surprisingly efficient to remove the aqueous Cs ion due to its small hydrated size and low hydration energy. But current experimental techniques fail in investigating deeply into the influence of some key electrode characteristics due to the difficulty in experimentally fabricating the electrodes as desired. This work presents a dynamic transport model of salt ions in a flow-by CDI cell. By using this model, the electrode thickness, macro- and micro-porosity are investigated to evaluate Cs ion removal efficiency and energy efficiency particularly from the aspect of ion transfer by the approach of decomposing energy contribution. The results indicate that the thick electrode coupled with the high current could greatly improve the effluent quality, but reduce the salt adsorption capacity (SAC). The increasement of the current density from 3 A/m2 to 6 A/m2 greatly decreases the SAC from 4.0 mg/g to 0.8 mg/g. Lower current could prolong the charging period, leading to more ions stored in the micropore. Not all the electrical energy is consumed for separating ions from the feed as desired, but some are used for driving ions diffusing in the electrodes. Consequently charging efficiency will be reduced especially when the electrodes are characterized with high porosity. It is highlighted that future work is required to further consider the complex details of porous structure and pore connectivity. [Display omitted] Radioactive cesium as the product of uranium fission in the energy industry usually exit in ionic form and could be easily dissolved in water, releasing high levels of beta as well as gamma particles and leading to cell damage. Surprisingly capacitive deionization (CDI) is efficient to remove the aqueous Cs ion due to its small hydrated size and low hydration energy. This work deeply elucidates the mechanism of Cs removal by the CDI technique from the aspect of ion transfer and energy contribution composition such as to provide theoretical guidelines for tailoring the electrode structure and tuning the operating parameters. • A CDI dynamic model was presented. • Mechanism was explained by ion transfer. • Energy was decomposed based on ion transport. [ABSTRACT FROM AUTHOR]

Bottom ashes generated from municipal solid waste incineration have gained increasing popularity as alternative construction materials, however, they contains elevated heavy metals posing a challenge for its free usage. Different leaching methods are developed to quantify leaching potential of incineration bottom ashes meanwhile guide its environmentally friendly application. Yet, there are diverse IBA applications while the in situ environment is always complicated, challenging its legislation. In this study, leaching tests were conveyed using batch and column leaching methods with seawater as opposed to deionized water, to unveil the metal leaching potential of IBA subjected to salty environment, which is commonly encountered when using IBA in land reclamation yet not well understood. Statistical analysis for different leaching methods suggested disparate performance between seawater and deionized water primarily ascribed to ionic strength. Impacts of leachant are metal-specific dependent on leaching methods and have a function of intrinsic characteristics of incineration bottom ashes. Leaching performances were further compared on additional perspectives, e.g. leaching approach and liquid to solid ratio, indicating sophisticated leaching potentials dominated by combined geochemistry. It is necessary to develop application-oriented leaching methods with corresponding leaching criteria to preclude discriminations between different applications, e.g. , terrestrial applications vs . land reclamation. [ABSTRACT FROM AUTHOR]

Technetium-99m (99mTc) is an important medical radionuclide. Due to the crisis in supply of molybdenum-99 (99Mo), production of 99mTc directly via the 100Mo (p, 2 n) reaction by cyclotron was proposed. In this process, the most critical challenge is to rapidly and efficiently separate 99mTc from high concentration of molybdenum. In this work, a novel ligand, bis(N,N -dibutyldiglycolamide)dibenzo-18-crown-6 (BisDBDGA-DB18C6) was successfully synthesized and used for extraction of TcO 4 - /ReO 4 - from molybdenum. The results demonstrated that BisDBDGA-DB18C6 expressed excellent selectivity for TcO 4 - with a high separation factor of 1.6 × 105 against Mo, a fast extraction kinetic (within 45 s), and a high extraction capacity of 211 mmol ReO 4 - (99TcO 4 -)/per mole of extractant. The extraction mechanism was proposed as a co-interaction of macrocyclic crown ether and N,N -dibutyldiglycolamide group through slope analysis, FT-IR, ESI-MS, 1H NMR titration and theory calculations. Importantly, 99Tc in the organic phase can be quantitatively (> 99%) and easily back-extracted using deionized water, which can be directly used for medical applications. [Display omitted] • A novel ligand BisDBDGA-DB18C6 was first prepared. • The tailored BisDBDGA-DB18C6 exhibits ultrafast extraction kinetic (within 45 s). • Superior extraction performance toward Tc/Re over Mo is confirmed and evaluated. • The solution is stripped with deionized water for direct medical applications. [ABSTRACT FROM AUTHOR]

Cadmium pollution is a serious threat for the global drink water and natural environment. Herein, a poly-pyrrole coated dual-metal perovskite-type oxide FeMnO 3 (PFMO@PPy) was developed firstly as pseudocapacitive cathode for the reversible capture and release of cadmium ions by asymmetry pseudocapacitive deionization (APCDI) technology, extending the library of CDI electrodes. Our work highlighted several points: (i) PFMO@PPy achieved a maximum Cd-removal capacity of 144.6 mg g−1, and maintained the retention rate of 93.4% after 15-cycle CDI process for up to 150 h, far beyond other previous work. (ii) PFMO@PPy showed the superior removal ratio (~90%) under different real water environments such as tap water, lake water and the groundwater. (iii) The superior Cd(II) electrosorption and desorption behavior is ascribed to the reversible synergistic valence conversion (Fe3+/Fe0 and Mn3+/Mn2+), which is confirmed by ex-situ XPS measurement and electrochemical tests. (iv) DFT calculations confirmed the synergistic effect from Mn and Fe elements in perovskite-type bimetallic oxide FeMnO 3. This study paves a new way for promising future applications of perovskite-type oxides containing dual Faradic redox-activity for wastewater treatment and environmental remediation. [Display omitted] • PFMO@PPy was studied firstly in CDI field and achieved a maximum Cd-removal capacity of 144.6 mg g−1. • PFMO@PPy maintained the retention rate of 93.4% after 15-cycle CDI process for up to 150 h. • PFMO@PPy obtained superior Cd-removal ratio (~90%) in tap water, lake water and groundwater. • Cd(II) adsorption behavior is ascribed to synergistic valence conversion (Fe3+/Fe0 and Mn3+/Mn2+). [ABSTRACT FROM AUTHOR]

The feasibility of the electro-removal of arsenate (As(V)) and arsenite (As(III)) from aqueous solutions via capacitive deionization was investigated. The effects of applied voltage (0.0–1.2 V) and initial concentration (0.1–200 mg L −1 ) on arsenic removal were examined. As evidenced, an enhancement of arsenic removal can be achieved by capacitive deionization. The capacity to remove As(V) at an initial concentration of 0.2 mg L −1 on the activated carbon electrode at 1.2 V was determined to be 2.47 × 10 −2 mg g −1 , which is 1.8-fold higher than that of As(III) (1.37 × 10 −2 mg g −1 ). Notably, the possible transformation of arsenic species was further characterized. The higher effectiveness of As(V) removal via electrosorption at 1.2 V was attributed to the formation of an electrical double layer at the electrode/solution interface. The removal of As(III) could be achieved by the oxidation of As(III) to As(V) and subsequent electrosorption of the As(V) onto the electrode surface of the anode. The presence of sodium chloride or natural organic matter was found to considerably decrease arsenic removal. Single-pass electrosorption-desorption experiments conducted at 1.2 V further demonstrated that capacitive deionization is a potential means of effectively removing arsenic from aqueous solutions. [ABSTRACT FROM AUTHOR]

This study presents the viability and preference of capacitive deionization (CDI) for removing different heavy metal ions in various conditions. The removal performance and mechanisms of three ions, cadmium (Cd 2+ ), lead (Pb 2+ ) and chromium (Cr 3+ ) were investigated individually and as a mixture under different applied voltages and ion concentrations. It was found that CDI could effectively remove these metals, and the performance was positively correlated with the applied voltage. When 1.2 V was applied into solution containing 0.5 mM individual ions, the Cd 2+ , Pb 2+ , and Cr 3+ removal was 32%, 43%, and 52%, respectively, and the electrosorption played a bigger role in Cd 2+ removal than for the other two ions. Interestingly, while the removal of Pb 2+ and Cr 3+ remained at a similar level of 46% in the mixture of three ions, the Cd 2+ removal significantly decreased to 14%. Similar patterns were observed when 0.05 mM was used to simulate natural contaminated water condition, but the removal efficiencies were much higher, with the removal of Pb 2+ , Cr 3+ , and Cd 2+ increased to 81%, 78%, and 42%, respectively. The low valence charge and lack of physical sorption of Cd 2+ were believed to be the reason for the removal behavior, and advanced microscopic analysis showed clear deposits of metal ions on the cathode surface after operation. [ABSTRACT FROM AUTHOR]

The presence of 1,4-dioxane in various water streams poses a threat to the health of human beings. In this study, the oxidative combination of ozone with peroxymonosulfate (PMS) was for the first time used to remove 1,4-dioxane from water. Near complete abatement of 1,4-dioxane was achieved by ozone-PMS after reaction of only 15 min and the degradation kinetics was found to be positively correlated with doses of PMS and ozone. Ozone-PMS oxidation had the optimum performance at slight base pH values. Both sulfate radicals and hydroxyl radicals were generated in ozone-PMS oxidation and these radicals resulted in the degradation of 1,4-dioxane. The effects of common water constituents and real water matrices were investigated. It was found that bicarbonate ions with a concentration up to 10 mM had a slight promoting effect, while either chloride ions or natural organic matter inhibited only slightly the degradation. Meanwhile, no obvious difference in the degradation of 1,4-dioxane was found among the real water matrices and deionized water, which demonstrates that ozone-PMS oxidation has high tolerance and stability. The results from this study demonstrate that ozone-PMS may be a promising technology for the removal of 1,4-dioxane from various water matrices. [Display omitted] • The activation of ozone by PMS mainly contributed to the degradation. • Both sulfate radicals and hydroxyl radicals were involved during the degradation. • Limited water matrices effects were observed on ozone-PMS oxidation. • Ozone-PMS oxidation showed high tolerance in the removal of 1,4-dioxane. • Two pathways were proposed for the degradation of 1,4-dioxane. [ABSTRACT FROM AUTHOR]

90Sr-containing radioactive wastewater during Fukushima nuclear accident (FNA) aroused extensive consideration for its disposal. Massive coexisted Na+ ions seriously inhibited Sr2+ removal, aggravating the expenditure of radioactive wastewater treatment. Herein, a chestnut shell derived porous carbon material modified with aryl diazonium salt (ADS) of sodium 4-aminoazobenzene-4′-sulfonate (SPAC) was developed as capacitive deionization electrode for selective removal of Sr2+ from saliferous radioactive wastewater. Based on ADS modification, the Sr2+ electrosorption capacity of SPAC electrode was improved to 33.11 mg g−1 with fast ion removal rate of 2.89 mg g−1 min−1, comparing with only 16.10 mg g−1 before modification. The isothermal adsorption and kinetics by SPAC electrode fitted well with Langmuir and pseudo-second-order model, achieving a maximum Sr2+ electrosorption capacity of 58.21 mg g−1, superior cycling stability, and excellent charge efficiency (77.63%). Fascinatingly, the SPAC electrode exhibited superhigh Sr2+ selectivity of 70.65 against Na+ in Na+–Sr2+ mixed solution with molar ratio of Na+:Sr2+ as 20:1. Density functional theory (DFT) simulation, combining with electrochemical and spectral analyses, revealed that the high overlap of electron cloud between Sr2+ ion and anionic sulfonic group (–SO 3 -) provided SPAC with remarkable selectivity of Sr2+ ion, and illustrated the ion-swapping mechanism of Sr2+ selectivity. [Display omitted] • SPAC electrode exhibited Sr2+ selectivity of 70.65 against Na+ in molar ratio of Na+:Sr2+ as 20:1. • A maximum Sr2+ electrosorption capacity of 58.21 mg g−1 was achieved in certain condition. • High overlap of electron cloud between Sr2+ ion and –SO 3 - group provided Sr2+ selectivity of SPAC. [ABSTRACT FROM AUTHOR]

Olive mill wastewater (OMWW) is an environmentally critical effluent, specifically due to its high content of phenolic compounds (PCs), which are hazardous due to their antimicrobial activities in water. However, their properties have good health effects at suitable doses. For the first time, the electrosorption of PCs from actual OMWW has been proposed for their possible recovery as value-added compounds, while decontaminating OMWW. A bio-sourced alginate-activated carbon (AC) fixed-bed electrode was prepared based on the reuse of olive pomace solid waste as powdered AC. At the optimal AC content (1% w/v), the internal ohmic drop voltage was lower (2.26 V) and the mass transport coefficient was higher (9.7 10−5 m s−1) along with the diffusivity (7.3 10−9 m2 s−1), which led to enhanced electrosorption rates. Afterward, an optimal electrode potential was obtained (−1.1 V vs. Ag/AgCl), while higher voltages led to faradaic reactions. Moreover, the adsorption capacity was lower (123 mg g−1) than that of electrosorption (170 mg g−1) and was even higher (307 mg g−1) with actual effluents. This was probably due to the influence of electromigration, which was confirmed by new models that could predict the electrosorption kinetics well considering mass transport and acid dissociation constants. [Display omitted] • Electrosorption of phenolic compounds with real olive mill effluents for the first time. • New model of phenol electrosorption kinetics including transport in transient regime. • Electro-migration was added to diffusion in electrosorption model of real effluent. • Mass transport was correlated with the activated carbon content in alginate beads. • Electrosorption occurred mainly within the beads and not at the electrode interface. [ABSTRACT FROM AUTHOR]

Iron-cobalt layered double hydroxides (FeCoLDH) showed superior oxygen evolution reaction (OER) performance, but the sluggish water adsorption and dissociation dynamics restrict its capacity to degrade organic pollutants by electro-oxidation. Herein, enhanced electro-oxidation performance of FeCoLDH with hydrophilic structure was designed and exhibited efficient removal efficiency of tetracycline. Theoretical calculation and characterization results consistently elucidated that the electronic structure of FeCoLDH is optimized by doping phosphorus and depositing copper nanodots (NDs). In addition, the obtained Cu NDs/P-FeCoLDH shows higher degradation ability of tetracycline in all-pH conditions than pristine FeCoLDH. That's because it owns smaller barrier with 0.6 eV to generate hydroxyl radicals (•OH) than pristine FeCoLDH. Furthermore, it can effectively degrade organic pollutants in seawater, river water and pharmaceutical wastewater samples. This work provides novel and rational electrode materials for electro-oxidation system with practical application potential, which could offer new insights into the fundamental understanding of electrochemistry. [Display omitted] • Cu NDs/P-FeCoLDHanode exhibits superior degradation efficiency of TC in all-pH conditions • P doping optimizedtheadsorption energies of hydrogen • Cu NDs deposition accelerateddissociation ofwater molecules • Reasonable mechanismfor the enhanced electrooxidation activity was well explained [ABSTRACT FROM AUTHOR]

Antibiotic resistance genes (ARGs) and their host antibiotic-resistant bacteria (ARB) are widely detected in the environment and pose a threat to human health. Traditional disinfection in water treatment plants cannot effectively remove ARGs and ARB. This study explored the potential of a heterogeneous photo-Fenton-like process utilizing a hierarchical macro-mesoporous Co 3 O 4 -SiO 2 (MM CS) catalyst for activation of peroxymonosulfate (PMS) to inactivate ARB and degrade the intracellular ARGs. A typical gram-negative antibiotic-resistant bacteria called Pseudomonas sp. HLS-6 was used as a model ARB. A completed inactivation of ARB at ∼107 CFU/mL was achieved in 30 s, and an efficient removal rate of more than 4.0 log for specific ARGs (sul1 and intI1) was achieved within 60 min by the MM CS-based heterogeneous photo-Fenton-like process under visible light and neutral pH conditions. Mechanism investigation revealed that •O 2 − and 1O 2 were the vital reactive species for ARB inactivation and ARG degradation. The formation and transformation of the active species were proposed. Furthermore, the hierarchical macro-mesoporous structure of MM CS provided excellent optical and photoelectrochemical properties that promoted the cycle of Co3+/Co2+ and the effective utilization of PMS. This process was validated to be effective in various water matrices, including deionized water, underground water, source water, and secondary effluent wastewater. Collectively, this work demonstrated that the MM CS-based heterogeneous photo-Fenton-like process is a promising technology for controlling the spread of antibiotic resistance in aquatic environments. [Display omitted] ● The ARB (HLS-6) can be inactivated in 30 s by MM CS/PMS photo-Fenton-like system. ● The related ARGs (sul1 and intI1) can be completely damaged in 30 min ● Hierarchical pores and visible light accelerated the reduction of Co3+ to Co2+. ● •O 2 − and 1O 2 were the vital reactive species for ARB inactivation and ARG removal. ● This MM CS/PMS photo-Fenton-like process was effective in various water matrices [ABSTRACT FROM AUTHOR]

This study was performed to determine the feasibility of electrosorptive removal of copper ions from aqueous solutions using a capacitive deionization process. The electrosorptive potential of copper ions was determined using cyclic voltammetry measurements, and copper electrodeposition could be suppressed at a voltage less than 0.8 V. Importantly, the experimental results demonstrated a significant enhancement of electrosorption capability of copper ions using the activated carbon electrodes under electro-assistance, associated with electrical double-layer charging. At 0.8 V, the equilibrium electrosorption capacity was enhanced to 24.57 mg/g based on the Langmuir model, and the electrosorption constant rate was increased to 0.038 min-1 simulated by a first-order kinetics model. Moreover, the activated carbon electrode showed great regeneration performance for the removal of low level copper ions. Additional experiments regarding electrosorption selectivity were performed in the presence of sodium chloride, natural organic matter, or dissolved silica. Copper ions that were preferentially electroadsorbed on the electrode surface can be effectively removed in a competitive environment. Therefore, the electrosorption process using activated carbon electrodes can be recommended to treat copper solutions at low concentrations for wastewater treatment and water purification. [ABSTRACT FROM AUTHOR]

As(III) removal from groundwaters is challenging because of its neutral charge and low surface affinity under circumneutral pH conditions. In this work, we investigate the influence of Ca2+ and Mg2+ on the removal of As(III) by a redox active polyvinylferrocene (PVF) functionalized electrode in a modified double potential step chronoamperometry (DPSC) setup. In the absence of divalent cations, nearly 90% As(III) removal is achieved over ten continuous cycles by single-pass DPSC, even in the presence of competing anions, however the presence of divalent cations at concentrations ≥ 1.25 mM significantly inhibits As(III) removal. The divalent cations enhance arsenic removal in the first (removal) step but suppress electrode regeneration in the 2nd step. Our results suggest that Ca2+/Mg2+ either acts as a bridge between the electrode surface and As anions or the sorption of Ca2+/Mg2+ increases the positive charge on the electrode surface thereby facilitating As(V) sorption. We show that effective electrode regeneration can be achieved using an NaOH wash however the overall complexity of the process increases. Overall, we conclude that the influence of divalent cations on As removal by electro-sorption processes needs to be taken into consideration for application of this technology for real groundwater treatment. [Display omitted] • Double Potential Step Chronoamperometry (DPSC) effectively removes As from solution. • Divalent cations Ca2+ and Mg2+ seriously inhibit As removal by DPSC. • Cations enhance As removal in 1st step but limit electrode regeneration in 2nd step. • Ca2+ and Mg2+ act as bridge between As and the polyvinylferrocene electrode. • Effective electrode regeneration can be achieved using an NaOH wash. [ABSTRACT FROM AUTHOR]

MXenes are a new type of two-dimensional (2D) material which are rapidly gaining traction for a range of environmental, chemical and medical applications. MXenes and MXene-composites exhibit high surface area, superlative chemical stability, thermal conductivity, hydrophilicity and are environmentally compatible. Consequently, MXenes have been successfully employed for hydrogen storage, semiconductor manufacture and lithium ion batteries. In recent years, MXenes have been utilized in numerous environmental applications for treating contaminated surface waters, ground and industrial/ municipal wastewaters and for desalination, often outperforming conventional materials in each field. MXene-composites can adsorb multiple organic and inorganic contaminants, and undergo Faradaic capacitive deionization (CDI) when utilized for electrochemical applications. This approach allows for a significant decrease in the energy demand by overcoming the concentration polarization limitation of conventional CDI electrodes, offering a solution for low-energy desalination of brackish waters. This article presents a state-of-the-art review on water treatment and desalination applications of MXenes and MXene-composites. An investigation into the kinetics and isotherms is presented, as well as the impact of water constituents and operating conditions are also discussed. The applications of MXenes for CDI, pervaporation desalination and solar thermal desalination are also examined based on the reviewed literature. The effects of the water composition and operational protocols on the regeneration efficacy and long-term usage are also highlighted. [Display omitted] • MXenes can be used for drinking / wastewater treatment and desalination applications. • Electrostatic and chemical interactions play a key role in adsorption via MXenes. • CDI electrodes with MXenes offer exceptionally high salt adsorption capacity. • MXenes also show intriguing results for pervaporation and solar desalination. • Assessment of the toxicity of MXenes is warranted before their widespread use. [ABSTRACT FROM AUTHOR]

Arsenite (As(III)) is more toxic and difficult to remove than arsenate (As(V)). In this study, an S-doped Cu-La bimetallic oxide (S-CuLaO) decorated with metal-organic framework (MOF) composite (S-CuLaO@UIO-66) was synthesized and applied for the adsorption of As(III). The maximum adsorption capacity of As(III) by S-CuLaO@UIO-66 was as high as 171 mg/g, which was much higher compared with other MOF compounds reported to date. The UIO-66 support improved the dispersion and reduced the size of the S-CuLaO particles, which increased the number of exposed adsorption reactive sites. Study of the mechanism revealed that the synchronous oxidation and adsorption significantly increased the removal of As(III). O 2 ∙ - was produced by the receiving electron from the dissolved oxygen from Cu(I) in S-CuLaO, which converted As(III) to As(V). Furthermore, the stability and reusability S-CuLaO@UIO-66 (without regeneration) was investigated at a low As(III) concentration (approximately 1000 µg/L) in deionized water and well water. The residual arsenic concentration ranged from 0.8 to 2.8 μg/L in deionized water and 3–58.2 μg/L in well water within 240 min during three cycles. Generally, this study suggests that combining an optimal oxide with a stable MOF is a promising approach for the fabrication of composite adsorbents. [Display omitted] • S-CuLaO@UIO-66 was successfully fabricated via decorating S-CuLaO to MOF (UIO-66). • S-CuLaO@UIO-66 was used for As(III) removal via simultaneous oxidation and adsorption. • O 2 ∙- resulted from the interaction of O 2 with Cu(I) was responsible for the oxidation of As(III). • Maximum adsorption capacity of S-CuLaO@UIO-66 towards As(III) was up to 171 mg/g. [ABSTRACT FROM AUTHOR]

Polyimide nanofiber (PINF) aerogel materials have received extensive attention as heat insulation, sensors and filtration media due to their excellent thermodynamic properties and unique porous structure. However, PINF must be difficult to disperse in organic solvents (dioxane or dimethyl sulfoxide) and dimensional instability has been regarded as issues that limits the preparation of PINF aerogels, especially in the water. So, it is of great significance to prepare polyimide aerogels with stable structure using water as a dispersant. In this work, the electrospun polyimide nanofiber precursor (polyamic acid (PAA) nanofiber (PAANF)) is uniformly dispersed in water, and triethylamine is added to terminated PAA oligomer as a binder. The resultant PINF aerogel has excellent mechanical properties with outstanding elasticity and a maximum compressive stress of 7.03 kpa at 50% strain. Furthermore, due to the extremely high porosity (98.4%) and hierarchical porous structure, the aerogel exhibits a high filtration efficiency (99.83%) for PM2.5, while the pressure drop is lower than that of the corresponding nanofiber membrane materials, which will facilitate its application in high temperature filtration and other fields. [Display omitted] • Creative use of deionized water as a dispersant to prepare PINF aerogel. • The preparation of PINF aerogel is only through the simple assembly of nanofibers. • The resultant PINF aerogel has excellent mechanical properties with outstanding elasticity. • The aerogel exhibits a high filtration efficiency (99.83%) of PM2.5 for particle matter. [ABSTRACT FROM AUTHOR]

A 250-day batch experiment was conducted to examine the generation of microplastic particles from degradation of polycarbonate films in 3 aqueous media of environmental relevance. The microplastic particles generated from the experiment were characterized by SEM/EDS and micro-FTIR analysis. Hydrolysis was responsible for the cleavage of carbon-oxygen bonds in the carbonate group of polycarbonate backbone and detachment of micro-sized plastic particles from the PC film surfaces. The deionized water treatment had the highest concentration of total organic carbon and the greatest number of microplastic particles among the three treatments. Either elevated acidity or the presence of hydroxyl radical did not enhance the hydrolytic degradation of the PC films and generation of microplastic particles though hydroxyl radical caused oxidative degradation of polycarbonate by attacking the organic group but not the carbonate group. Bisphenol A was not detected in any of the treatments. The microplastic particles generated from the current experiment were highly irregular, which may have different physicochemical and toxic behaviours from the spheric synthetic ones that were frequently used in toxicity experiments. [Display omitted] • Experiment to examine weathering of polycarbonate (PC) films in aqueous media. • Elevated acidity or hydroxyl radical did not enhance the degradation of PC films. • Hydrolysis was responsible for generating microplastics with irregular shapes. • Alkanes but not bisphenol A was detected in solutions in contact with the PC films. • Implications for PC degradation under conditions of environmental relevance. [ABSTRACT FROM AUTHOR]

The improper disposal in agricultural and industrial wastewater leads to high NO 2 – concentrations in the aquatic environment, which can cause cancer in humans and animals; thus, their quick and accurate detection is urgently needed to ensure public health and environmental safety. In this study, a reliable and selective electrochemical sensor consisting of Pd–Cu nanospheres (NSs) supported on molybdenum carbide was prepared via simple ultrasonication. Then, a glassy carbon electrode was realized using this composite (Pd-Cu-Mo 2 C-modified GCE) to test its electrocatalytic sensing for NO 2 – in a 0.1 M phosphate-buffered solution (PBS) solution via cyclic voltammetry and amperometry; at a low oxidation potential, the anodic peak current of NO 2 – detected by this electrode was significantly higher than that of its unmodified and other modified electrodes. The sensor showed a broad linear response in the 5–165-nM NO 2 – concentration range, with a low detection limit (0.35 nM in 0.1 M PBS) and high sensitivity (3.308 μAnM–1 cm–2). Moreover, the fabricated electrode was successfully applied for detecting nitrites in sausages, river water, and milk, showing also good recovery. ga1 • Facile synthesis of Pd–Cu NSs decorated on Mo 2 C via ultrasonication techniques. • The proposed sensor has a wide linear response and ultralow LOD (0.35 nM) for NO 2 –. • Good stability, repeatability, and antipoisoning capability achieved for NO 2 –. • The modified electrode can detect NO 2 – also in contaminated samples. [ABSTRACT FROM AUTHOR]

Novel particle electrodes, i.e. flotation tailings particle electrode (FPE), were prepared using flotation tailings, garden soil, and soluble starch with a mass ratio of 16:3:1, and then used in tetracycline wastewater treatment. The physicochemical properties of FPE were systematically characterized using SEM, XRD, FT-IR and XRF. Tetracycline adsorption and its adsorption mechanism onto FPE was explored for the first time. Parameters affecting FPE's degradation efficiency and energy consumption such as current density, electrolysis time, initial concentration, initial pH and aeration rate were examined. The electrocatalytic degradation of tetracycline shows that the degradation of tetracycline meets the pseudo-first-order kinetics. Moreover, the numbers of •OH produced on the surfaces of the cathode, anode and particle electrode were compared. Results showed that the adsorption-saturated FPE can be regenerated by electrochemical action to induce further absorption and form in-situ electrocatalysis. In order to find out the transformation products in water and degradation pathways of Tetracycline, UHPLC method was used to obtain the degradation pathways for Tetracycline. So, this work could provide a fabrication of high-efficiency and low-cost electrocatalytic for removal of pharmaceuticals pollutants from waste water as well as deeper insight into electrocatalytic mechanism, transformation products, and degradation pathways of Tetracycline in water. ga1 • FPE were prepared as novel particle electrodes mainly using the flotation tailings. • TC could be effectively adsorbed by FPE. • Key factors on TC of 3D-AER degradation were evaluated. • Degradation mechanism under 3D-AER with FPE was proposed. • Degradation pathways were speculated with several typical intermediates identified. [ABSTRACT FROM AUTHOR]

• A process for hazard-free treatment electrolytic manganese residue (EMR) was proposed. • Almost all of the ammonia in the EMR was recovered by low-temperature roasting. • The manganese present in the EMR could be recovered by countercurrent water-washing. • The toxicity leaching results of the EMR after hazard-free treatment met GB 8978−1996. A combined low-temperature-roasting and water-washing process is investigated as a hazard-free method to treat electrolytic manganese residue (EMR) and recover manganese. In this study, the phase transformation characteristics and a thermodynamics analysis of the low temperature roasting process of EMR are evaluated. In addition, the effects of temperature and time on the phase transformation of EMR in the roasting process and the washing characteristics of roasted EMR samples are also investigated. Results reveal that some unstable phases within EMR are transformed into more stable phases depending on the treatment time/temperature conditions used and EMR roasted for 60 min at 600 °C (R 60min/600°C) exhibit the highest rate of manganese recovery, 67.12 %. After 25 min of deionized water washing, the concentration of manganese in solution from R 60min/600°C material become stable, whereas after 6 washing cycles the concentration of manganese in the solution is < 0.005 g/L. The R 60min/600°C material with three wash cycles results in a manganese-water solution concentration that is suitable for use in electrolytic manganese metal production. Finally, toxicity leaching tests show that the concentrations of ions present in the leaching solution are all lower than the regulatory limits mandated by the Chinese Integrated Wastewater Discharge Standard GB 8978−1996. [ABSTRACT FROM AUTHOR]

• CZTS nanoparticles synthesized with solvents of deionized water and ethylene glycol were utilized in catalytic H 2 O 2 process. • CZTS-W exhibited higher recyclability and stability than CZTS-EG. • 1O 2 played the dominant role in SDZ degradation. • The catalytic mechanisms of CZTS-W/H 2 O 2 and CZTS-EG/H 2 O 2 systems were proposed. • The synergetic effect of Cu2+/Cu+ and low-valent sulfur/high-valent sulfur was in favor of H 2 O 2 activation. As a quaternary copper-based semiconductor, Cu 2 ZnSnS 4 (CZTS) is drawing growing attention and is anticipated as a promising photocatalyst, thanks to its large absorption coefficient, exceptional photostability, and theoretical power conversion efficiency. However, CZTS has never been used as an activator of H 2 O 2 for the degradation of refractory organic pollutants. In this study, the synthesis of CZTS nanoparticles obtained with diverse morphologies and crystallinities using solvents of deionized water (CZTS-W) and ethylene glycol (CZTS-EG) was examined in the activation of H 2 O 2 to degrade sulfadiazine (SDZ). The results revealed that CZTS coupled with H 2 O 2 could be an effective system for the degradation of SDZ. Compared to CZTS-EG, CZTS-W presented higher reusability in consecutive cycles with negligible leaching of copper. Reactive oxygen species quenching tests and electron paramagnetic resonance analyses illustrated that •O 2 −, •OH, and 1O 2 contributed to the degradation of SDZ, and 1O 2 prevailed over •O 2 − and •OH. The mechanistic investigation showed that efficient degradation could be associated to the effective recycling of Cu(II)/Cu(I) and low-valent/high-valent sulfur. Also, the degradation pathways of SDZ have been proposed through the detection of intermediate products. This study manifests that CZTS synthesized using deionized water is encouraging for the elimination of organic pollutants. [ABSTRACT FROM AUTHOR]

• Hg (II) adsorption was compared for modified and unmodified pine-needle biochars. • S-modified pine-needle biochar (BC–S) showed higher Hg (II) adsorption. • Hg (II) removal by BC–S was best described by pseudo-second-order kinetics. • The removal was occurred by complexation with S-containing functional groups. • BC–S resulted in insignificant S leaching to the surrounding aqueous phase. Sulfur-modified pine-needle biochar (BC–S) was produced for the removal of Hg(II) in aqueous media via post-pyrolysis S stream exposure. Fourier-transform infrared spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy confirmed the addition of S(0) groups on the surface of BC–S. Hg(II) adsorption on BC–S was best described by the Freundlich isotherm with a K F of 21.0 mg L g−1 and a pseudo-second-order adsorption kinetics model with a rate of 0.35 g mg−1 min−1. Hg(II) removal on BC–S was found to be an endothermic process that relied on C-Hg and S-Hg interactions rather than reduction by S(0) groups. The adsorption increased with increasing solution pH and decreased with increasing dissolved organic matter concentration, but was unaffected by increasing salt concentrations. BC–S showed a maximum of 3 % S leaching in aqueous media after 28-d exposure time, and exposure to aqueous media did not convert Hg(II) to elemental Hg. Overall, BC–S exhibited superior Hg(II) removal performance over unmodified BC, thus having potential applications in natural water and wastewater treatment with no significant threat of secondary pollution. [ABSTRACT FROM AUTHOR]

• Bulk electrochemical oxidation is seemingly beneficial for petroleum spill clean-up. • Active chlorine is effective for the removal of naphthalene and its derivatives. • Carbon electrodes are inexpensive and competent for bulk removal of organics. • A dynamic kinetic model is proposed that can accurately predict treatment outcomes. • Energy consumption is low enough for use in remote environmental remediation. This work assesses the potential of electrochemical technologies for the treatment of groundwaters contaminated with petroleum hydrocarbons. Specific consideration was given to deployment in Antarctic regions where numerous fuel spills have occurred over the last two centuries, and resources and manual labour for remediation efforts are limited. The polycyclic aromatic hydrocarbon, naphthalene, was a used as a model contaminant and was treated with low-cost, active carbon electrodes to promote the active chlorine degradation pathway. Results showed that 20 mg/L naphthalene solutions could be treated to sufficient standards in less than 3 h of treatment, and that the formation of toxic and chlorinated by-products is not an issue of concern if the appropriate timeframes are used (4 h of treatment). The effects of the applied current (0–160 mA) and electrolyte concentration (0.01–0.1 M NaCl) were evaluated and a dynamic kinetic model proposed and found to be in good agreement with the experimental results. The energy consumption is an important limitation in remote environmental regions where resources are scarce. It was found that an energy usage of 104 kW h/kg of naphthalene removed could be achieved. [ABSTRACT FROM AUTHOR]

• 17beta-hydroxysteroid dehydrogenases type 2 enzyme is responsible for the oxidation of sex-hormones. • We used microarray technology to analyze the effect of 17β-HSD2 on MCF-7 cell transcript profile. • 542 genes were regulated 1.5 fold or higher after treatment with 17β-HSD2 siRNA. • It indicated that 17β-HSD2 is not only hormone-dependent, but also playing hormone-independent roles. A high-performance carbon electrode is desirable for promoting electrochemical desalination efficiency in the membrane capacitive deionization (MCDI). Sugarcane bagasse (food waste) was employed in this study to prepare hierarchically porous biochars by microwave-assisted carbonization and activation with potassium hydroxide in N 2 or CO 2 atmosphere under varying flow rates (100-600 cm3 min−1). The sugarcane bagasse-derived biochars activated under CO 2 flow of 300 cm3 min−1 (denoted as SBB-CO 2 -300) possessed the ratio of mesopores to total pore volume (V meso /V total) of 56.7% with a specific surface area of 1019 m2 g−1. The electrochemical behavior of SBB-CO 2 -300 was demonstrated by a surpassing specific capacitance of 208 F g−1 at 5 mV s−1 by means of cyclic voltammetry. The desalination tests using a batch-mode MCDI at 1.2 V in a 5 mM NaCl solution indicated that the SBB-CO 2 -300 electrode exhibited an excellent electrosorption capacity of 28.9 mg g-1. The improvement in the electrochemical deionization performance of SBB-CO 2 -300 was attributed to the superior V meso /V total ratio, high surface area, excellent capacitance behavior, and hierarchical pore structure. The biowaste-derived biochars prepared via facile microwave-assisted carbonization and CO 2 activation route can provide a sustainable and high-efficiency carbon electrode for electrochemical deionization of brackish water. [ABSTRACT FROM AUTHOR]

• Alum sludge and melamine was co-pyrolyzed to synthesize a composite. • The composite can oxidize As(III) to As(V) under the light condition. • Oxidized As(V) was adsorbed onto the composite via chemisorption. The oxidation of trivalent arsenic (As(III)) to pentavalent arsenic (As(V)) is a common pretreatment to remove As(III) from the aqueous phase. The graphitic carbon nitride as a photocatalyst can transform As(III) to As(V), but the photocatalyst does not adsorb any species of arsenic. In this study, a new composite material to achieve the simultaneous oxidation and adsorption of arsenic was synthesized by co-pyrolyzing alum sludge and melamine. It was hypothesized that graphitic carbon nitride derived from melamine oxidizes As(III) to As(V) and pyrolyzed alum sludge provides strong adsorption sites for the oxidized As(V). The composites were characterized by X-ray diffraction, Brunauer-Emmett-Teller(BET) surface, scanning electron microscope, and X-ray photoelectron spectrometer. The composite material effectively converted As(III) to As(V) under the light, and the total arsenic concentration decreased in the aqueous phase via the adsorption of As(V). Speciation analysis of arsenic on the composite showed that both As(III) and As(V) species were present on the surface of adsorbent, from which desorption by mixing with deionized water was difficult. This new and green composite material can oxidize As(III) and adsorb arsenic simultaneously under the light, which can be used to treat arsenic-containing water. [ABSTRACT FROM AUTHOR]

Three-stage operation system (3S A–C system) combining adsorption and CDI is efficient in recovering liquid fertilizers from wastewater and is a promising technology for simultaneously addressing nutrient crises and environmental pollution. • Hydrogel adsorbents have good separation ability for metal cation and anion. • Hydrogel adsorbents showed little removal of nutrients. • 3S A–C system was presented for nutrient recovery and wastewater treatment. • Plants using recovered liquid fertilizers revealed excellent values. The recovery of nitrogen (N) and phosphorus (P) from wastewater is of great importance in addressing the global nutrient crisis. The limitations of existing methods require the development of effective technology. Here, two different hydrogel adsorbents were fabricated with good separation ability for metal cation (M+) and metal anion (M−) but showed little removal of nutrients. Based on the materials, a novel three-stage operation system combining adsorption and capacitive deionization (CDI) technology was presented for nutrient recovery and wastewater treatment. In the first two stages, mixed metals in wastewater were successfully separated (Cu2+: 144.6 mg/g; Cr 2 O 7 2−: 167.0 mg/g), and nutrients were retained (N and P < 1 mg/g). In the third stage, the residual trace metal ions in the solution were removed (2.0 mg/L to N/A), and the nutrients were enriched through electroadsorption and desorption processes by CDI. Plants using recovered liquid fertilizers revealed similar values for height, root length, and chlorophyll compared with those obtained using actual fertilizers. The results indicated that this novel three-stage operation system (3S A–C system) combining adsorption and CDI is efficient in recovering liquid fertilizers from wastewater and is a promising technology for simultaneously addressing nutrient crises and environmental pollution. [ABSTRACT FROM AUTHOR]

• Highly porous carbons were prepared from pyrolysis of dry loofah sponge using ZnCl 2. • MnO 2 /AC electrode was synthesized through KMnO 4 reduction. • Electrochemical mineralization of oxalic acid were performed over MnO 2 /AC electrode. • Phase transformation via calcination strongly improved effectiveness of MnO 2 redox. Manganese dioxide incorporated activated carbon (MnO 2 /AC) was synthesized and used to electrochemically degrade oxalic acid in aqueous solutions. The highly porous carbon provided reactive sites for the electro-sorption of oxalic acid and MnO 2 , with a specific polymorphism efficiently mediating the electron transfer between the electrode and organic pollutants. The activated carbon, made from the pyrolysis of dry loofah sponge using ZnCl 2 as activating agent, exhibited a high double-layer capacitance dependent upon the heating temperature (100 F/g at 800 °C). The γ -MnO 2 was in-situ deposited over the microporous structure of activated carbon through the redox reaction between KMnO 4 and carbon. Simple further calcination converted γ -MnO 2 to α -MnO 2 nano-whisker at temperatures above 500 °C. Cyclic voltammetry showed that oxalic acid significantly improved the anodic current of the Mn(III)/Mn(IV) redox couple on the MnO 2 /AC electrode at an electrode potential around + 0.6 V (vs. Ag/AgCl). About 95% of oxalic acid degradation was achieved at pH < 4; meanwhile, 80% of the mineralization (total organic carbon removal) was attained independent of pH. Calcination converted γ -MnO 2 to α -MnO 2 which had higher electrochemical stability and inhibited the dissolution of Mn(II) from the electrode. [ABSTRACT FROM AUTHOR]

• Silver-functionalized silica aerogel (AgAero) is novel material for iodine capture. • AgAero completely and fast removed I− from different aqueous environments. • AgAero exhibited a preferred removal of I− over Br− and Cl−. • AgAero was able to remove IO3- in DIW through reduction to I−. One of the key challenges for radioactive waste management is the efficient capture and immobilization of radioiodine, because of its radiotoxicity, high mobility in the environment, and long half-life (t 1/2 = 1.57 × 107 years). Silver-functionalized silica aerogel (AgAero) represents a strong candidate for safe sequestration of radioiodine from various nuclear waste streams and subsurface environments. Batch sorption experiments up to 10 days long were carried out in oxic and anoxic conditions in both deionized water (DIW) and various Hanford Site Waste Treatment Plant (WTP) off-gas condensate simulants containing from 5 to 10 ppm of iodide (I−) or iodate (IO 3 −). Also tested was the selectivity of AgAero towards I− in the presence of other halide anions. AgAero exhibited fast and complete removal of I− from DIW, slower but complete removal of I− from WTP off-gas simulants, preferred removal of I− over Br− and Cl−, and it demonstrated ability to remove IO 3 − through reduction to I−. [ABSTRACT FROM AUTHOR]

• Biochar can act as electron shuttle to mediate the electron from soil relevant organic acids to Cr(VI) reduction. • Redox reactions and sorption process occurred between biochar and LMWOAs, which provide the different electron shuttling way. • BC400 mediate the electron by the redox process with LMWOAs and tartaric acid had the best Cr(VI) reduction efficiency. • BC700 mediate the electron by the sorption process with LMWOAs and oxalic acid had the best Cr(VI) reduction efficiency. Biochar can act as "electron shuttle" in soil redox reactions. It is possible that biochar accepts the electrons from low molecular weight organic acids (LMWOAs) in soil and then transfer them to the acceptors, e.g., Cr(VI). This study evaluated the interaction between seven soil LMWOAs and peanut shell biochar (BC) as well as its effect on the electron shuttling of biochar for Cr(VI) reduction. Both redox reactions and sorption process occurred during the interaction of biochar and LMWOAs, which altered the contents of Cr(VI) reduction-relevant groups (i.e., C O and C O) on the surface of biochar. The redox reactions were more important to the electron transfer between biochar produced at 400℃ (BC400) and LMWOAs due to the repeated cycle of reduction-oxidation of surface functional groups. The reduction rate of Cr(VI) by LMWOAs mediated by BC400 was 1.10–7.09 × 10−3 h-1, among which tartaric acid had the best reduction efficiency due to its highest reducing capability. For biochar produced at 700℃ (BC700), the sorption process of LMWOAs was the key factor to the direct electron shuttling process through the conjugated structure of biochar. The reduction rate of Cr(VI) by LMWOAs mediated by BC700 was significantly higher and ranged 7.40–864 × 10−3 h-1, with the oxalic acid having the best reduction efficiency due to its highest sorption capacity by BC700. The results obtained from this study can help to establish the linkage between biochar and LMWOAs in soil electron network, which better explains the multifunctional roles of biochar during the redox processes such as Cr(VI) reduction in soil. [ABSTRACT FROM AUTHOR]