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[Display omitted] • FCDI effectively removes Cr (VI) from wastewater using CNT incorporated AC flow-electrode at lower voltage. • Coexisting ions have minimal impact on Cr (VI) removal efficiency. • FCDI transforms hazardous Cr (VI) to less toxic Cr (III) form. • CNT incorporation improves the contact efficiency and accelerates charge transfer between AC particles. The contamination of wastewater with hexavalent chromium (Cr (VI) poses significant health and environmental risks. To alleviate this challenge, our research explores the potential of flow electrodes capacitive deionization (FCDI) technique, an energy-efficient and environmentally friendly approach, for Cr (VI) removal and detoxification. We incorporated varying weight loadings of carbon nanotubes (CNTs) into activated carbon (AC) flowable electrodes, and assessed the system's performance under different operational conditions. Our findings revealed that by adding just 1.5 wt% CNT to AC and applying a voltage of 0.9 V, the current response increased 3.4 times compared to that of pure AC flowable electrode, resulting in a remarkable Cr (VI) removal efficiency of 99.5 %. This study also revealed that the presence of high concentrations of co-existed chloride ions (Cl−) did not significantly influence the efficiency of Cr (VI) removal. Incorporation of CNT in AC flow electrodes reduced the inter-tube aggregation and enhanced the contact efficiency between the AC particles, forming a connecting percolation network and enhancing the conductivity of the slurry electrodes for Cr (VI) removal. In addition to Cr (VI) removal, FCDI technique transformed extremely dangerous Cr (VI) to less toxic Cr (III) from 5.4 to 49.8 % during multiple cycles. In summary, we presented an innovative, efficient, eco-friendly approach for Cr (VI) removal and detoxicity by using CNTs incorporated electrodes, underscoring the potential FCDI technology in heavy metal disposal. [ABSTRACT FROM AUTHOR]

• The dissolution difficulty in metal chlorine solution followed the order of HgSO 4 < HgO < HgS. • NaCl, KCl, CeCl 3 , MnCl 2 , AlCl 3 , CaCl 2 , FeCl 3 , and CuCl 2 solutions could react with HgSO 4 to generate HgCl 2. • MnCl 2 , AlCl 3 , CaCl 2 , FeCl 3 , and CuCl 2 solutions could react with HgO to produce HgCl 2. • Only CuCl 2 could react with HgS to produce HgCl 2. • CuCl 2 solution could protect active site of metal oxide adsorbents and avoid the reduction of HgCl 2 to Hg 2 Cl 2. Washing regeneration of Hg adsorbent not only has good economic benefits, but also effectively avoids the secondary pollution of Hg caused by the accumulation or landfill of used Hg adsorbents. The common Hg-containing substances on used Hg adsorbent are HgS, HgO, HgSO 4 , and HgCl 2 , which requires the solution to be able to react with insoluble HgS, HgO, and HgSO 4 to produce easy-soluble HgCl 2. Considering the characteristics of containing Cl ion and oxidation capacity, metal chloride solution was chosen for washing regeneration of Hg adsorbent. In this study, the reaction between HgS, HgO, HgSO 4 and metal chlorine solutions including NaCl, KCl, CeCl 3 , MnCl 2 , AlCl 3 , CaCl 2 , FeCl 3 , and CuCl 2 were separately studied using thermodynamic calculation software (FactSage 5.2). The subsequent supporting experiments were also conducted for verifying the correctness of thermodynamic calculation. The results showed that without the input of external energy, all the NaCl, KCl, CeCl 3 , MnCl 2 , AlCl 3 , CaCl 2 , FeCl 3 , and CuCl 2 solutions could react with HgSO 4 to generate HgCl 2. While only MnCl 2 , AlCl 3 , CaCl 2 , FeCl 3 , and CuCl 2 solutions could react with HgO to produce HgCl 2 , and only CuCl 2 solution could react with HgS to produce HgCl 2. The leaching and dissolution difficulty in metal chlorine solution followed the increasing order of HgSO 4 < HgO < HgS. Finally, the feasibility of the precipitation method using NaOH solution for separating Hg2+ was verified by combining the thermodynamic calculation results, characterization and tests (ICP-OES and Hg-XPS) results. Considering CuCl 2 was the only solution that could react HgS, HgO, and HgSO 4 to produce HgCl 2 , and could protect active site of common metal oxide for Hg removal, as well as had a good oxidation ability for avoiding the reduction of HgCl 2 to insoluble Hg 2 Cl 2 , CuCl 2 solution was finally determined as the suitable solution for washing regeneration of Hg adsorbent. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic luffa sponge derived graphene aerogel incorporated with CuFe 2 O 4. • Aerogels with excellent superhydrophobic stability and high surface area. • High adsorption capacity and selectively with excellent recyclability. • Magnetic control technology for continuous oil–water separation. In this study, a novel magnetic composite material comprising luffa sponge derived graphene aerogel embedded with hollow CuFe 2 O 4 nanospheres (LGN) is successfully synthesised for the first time by a clean and low-cost one-step solvothermal electrostatic co-assembly method. The resultant LGN aerogel exhibits superhydrophobic and superoleophilic properties with the water and oil contact angles of 162.1° and 0°, respectively, along with magnetic properties characterized by the saturation magnetization of 51.6 emu/g, and a large specific surface area of 218.8 m2/g. The saturation sorption capacity of LGN for organic solvents/oil is found to be in the range of 47.6–86.8 g/g, exhibiting an excellent oil/water emulsion separation ability. Through the capillary action, oil and organic solvents spontaneously penetrate into the interior of the aerogel, while the superhydrophobic surface prevents water from entering, thereby enabling the separation of oil and water. These characteristics enable the real-time sorption of organic pollutants from water, with the capability of exhausted sorbent being regenerated. Notably, even after 20 sorption-volatilisation cycles, the saturated sorption capacity of LGN remains high at the 92.2 % of the initial value, demonstrating a remarkable recycling performance. In addition, LGN can exhibit an oriented sorption performance by controlling the applied magnetic field, enabling sorbent recycling even under extreme environmental conditions. Such an effective strategy offers a new route to high value utilisation of biomass waste with significant potential in the field of oil spill treatment. [ABSTRACT FROM AUTHOR]

• The influence of gasification medium on Hg0 release and oxidation were elucidated. • The inhibition and promotion of gasification products on Hg0 oxidation were explained. • The advantages and disadvantages of common OC on Hg0 oxidation were summarized. • The effects of reaction temperature and reactor configuration on Hg0 release and oxidation were introduced. • Appropriate H 2 O(g) content, OC with weak adsorption and strong oxidation capacity, and suitable AR temperature were suggested. Chemical looping combustion (CLC) of coal can effective achieve the capture and storage of CO 2 , reduce the emission of NO x , and realize the energy cascade utilization. During the process of CLC, mercury (Hg) will release from coal and enrich in gas. If Hg has not been effectively treated, it will not only cause the serious harm to human body and environment, but also affect the purification and storage of CO 2 by mixing with CO 2 , as well as lead to the corrosion of equipment, which highlights the importance of Hg removal in CLC. This review summarized the influence and mechanism of gasification medium (signal CO 2 , signal H 2 O vapor, as well as mixture of CO 2 and H 2 O vapor), gasification products (CO, H 2 , NH 3 , HCl, and H 2 S), oxygen carrier (single metal oxides of Fe 2 O 3 , MnO 2 , Co 3 O 4 , CuO, and CeO 2 , CaSO 4 , mixed OC, and natural-ores OC), reaction temperature, as well as reactor configuration in fuel reactor and air reactor on the release, oxidation, and transfer of Hg in CLC of coal. Based on these above, several suggestions about the selection of appropriate H 2 O(g) content to minimize the release of Hg and promote the oxidation of Hg0, the selection of OC with weak adsorption capacity and strong oxidation performance, the preparation and application of Cu, Mn, Co spinel structured oxides for promoting the catalytic oxidation of Hg0 in CLC high-temperature furnace, and the choice of an appropriate air reactor temperature to maximize the oxidation of Hg0 in the AR and reduce the escape of Hg from the AR outlet were provided for promoting the removal of Hg for CLC in the future. [ABSTRACT FROM AUTHOR]

• The novel washing regeneration methods for AC using CuCl 2 solution was proposed and verified. • CuCl 2 solution showed excellent performance on eluting Hg-containing compounds on spent AC. • Elution process restored the well-developed pore structure and reactive functional groups of AC. • CuCl 2 -AC showed a higher (above 99%) and more stable Hg removal performance than raw AC. • Hg-containing compounds on spent CuCl 2 -AC were mainly easy-soluble HgCl 2. Mercury pollution in syngas has received increasing attention. Regeneration of AC can reduce the cost and avoid Hg secondary release effectively. The performance of CuCl 2 solution on AC regeneration was studied combining fixed-bed reactor, Hg-TPD, and characterization tests (BET, SEM-EDS, XPS, and FT-IR). Hg adsorption on AC in N 2 mainly followed physisorption. There was a synergistic contribution of HCl and H 2 S on Hg removal, in which HCl promotion was stronger than H 2 S. The main Hg-containing compounds on AC in HCl were HgCl 2 and HgO, in H 2 S were HgO and HgS. The well-developed pore structure of AC enhanced Hg adsorption while inhibited the elution of Hg-containing compounds. CuCl 2 solution exhibited an excellent synergy in the elution of Hg-containing compounds and the impregnation modification of AC, which not only eluted the Hg-containing compounds, restored the well-developed pore structure, and recovered the reactive oxygen-containing functional groups effectively, but also brought in Cu and Cl for promoting Hg removal by generating Hg-Cu and HgCl 2 respectively. The best impregnation content of CuCl 2 was 10% that exhibited higher (above 99%) and more stable Hg removal efficiency than raw AC, and the dominant Hg-containing compound was easy-soluble HgCl 2 , proving the practicability of CuCl 2 solution on AC regeneration. [ABSTRACT FROM AUTHOR]

• The effects and mechanisms of CO, H 2 , NH 3 and HCl on HgS and HgO generation in H 2 S atmosphere were respectively clarified. • The species and stability of Hg-containing products in H 2 S + CO, H 2 S + H 2 , and H 2 S + NH 3 , and H 2 S + HCl were respectively determined. • The feasibility of adjusting the syngas components and modifying by CuCl 2 impregnation for promoting the solution washing regeneration were respectively evaluated. • The effect and promotional mechanism about the impregnation modification of CuCl 2 were respectively determined. Inhibiting the generation of insoluble HgO and HgS, as well as promoting the generation of HgCl 2 can significantly contribute to the solution washing regeneration of adsorbent for Hg removal in syngas. In this study, CeO 2 -MnO 2 /TiO 2 (Ce-Mn/Ti) was chosen as the Hg adsorbent, the fixed-bed test, Hg-TPD, and characterization test (including BET, SEM-EDS, and XPS) were conducted. Firstly, the effects of different concentrations of CO, H 2 , NH 3 , and HCl on the generation of HgS, HgO, and HgCl 2 on adsorbent was investigated. Although the increase of CO, H 2 , and NH 3 concentration can inhibit the generation of HgS and HgO to different extents, and the increase of HCl concentration can promote the production of HgCl 2 , but they will also lead to the increase in Hg concentration to varying degrees, indicating the adjustment on syngas components and concentrations is not a feasible method. Subsequently, the effects of different concentrations of modification reagent with CuCl 2 were studied. The optimal impregnation ratio of CuCl 2 was determined as 10%, in which the Hg removal efficiency in H 2 S atmosphere could reach over 97%, and almost of the Hg-containing product was easy-soluble HgCl 2. The great advantage of impregnation modification of CuCl 2 is attributed to the uniform and dense distribution of CuCl 2 , as well as the strong activity of CuCl 2 itself towards Hg0 oxidation to HgCl 2. The impregnation modification of CuCl 2 can significantly improve the Hg removal efficiency, inhibit the generation of HgS and HgO, and promote the generation of HgCl 2 , which is verified as a feasible method to improve the solution washing regeneration of Hg adsorbent. [ABSTRACT FROM AUTHOR]

[Display omitted] • rGS porous materials are developed for desalination of saline water with solar and electro energy supplies. • rGS materials are featured with both excellent solar-thermal and electro-thermal properties. • Water evaporation fluxes are > 1100 g m-2h−1 under 1 sun and > 3600 g m-2h−1 under 20 V (DC). • Salt rejection is always > 99.95% towards different saline waters in solar-/electro-thermal desalinations. • Portable desalination systems are designed to produce drinking water with solar energy or DC power supply. Desalination of saline water is a key technology to produce safe drinking water. Here, we report a novel type of reduced graphene oxide (GO) nanosheets modified porous functional materials (rGS) with both excellent solar-thermal and electro-thermal properties for efficient, portable, and continuous desalination of saline water. The rGS porous materials are prepared by modifying porous melamine sponges with GO nanosheets, and then reducing GO nanosheets into reduced GO (rGO) nanosheets. With sufficient rGO nanosheets coated on rGS porous materials, water evaporation fluxes of rGS-5 porous materials are > 1100 g m-2h−1 in solar-thermal desalination under 1000 W m−2 and > 3600 g m-2h−1 in electro-thermal desalination under direct voltage of 20 V due to the excellent solar-thermal property and Joule effect of rGS. The salt rejection values are always higher than 99.95% towards different saline waters including hypersaline water, and the salinities of distilled waters are always far lower than the WHO standard for safe drinking water. The strategy and results in this work provide valuable guidance for designing portable desalination systems to produce safe drinking water by simply using solar energy and/or direct-current power supply in certain applications with special needs such as remote regions and disaster situations. [ABSTRACT FROM AUTHOR]

[Display omitted] • A versatile superhydrophobic magnetic PDMS@CZIF-67/CS aerogel was firstly fabricated. • The carbonized ZIF-67 provided aerogel with magnetism for self-driven oil absorption. • The aerogel has photothermal conversion property for high viscosity oils absorption. • The aerogel exhibits excellent oil adsorption and oil/water separation performance. • The aerogel synchronously remove MPs and their derivatives, antibiotics, and dyes. Water resources contamination by both oil and microplastics (MPs) stands as a pressing environmental concern. To tackle this challenge, we have devised a superhydrophobic magnetic biomass aerogel, synthesized from PDMS-modified carbonized ZIF-67/chitosan (PDMS@CZIF-67/CS). This aerogel exhibits remarkable capabilities in oil/water separation and adsorption of a wide range of emerging pollutants due to its inherent superhydrophobicity, stability, and self-cleaning capabilities. Furthermore, the aerogel demonstrates efficient absorption of viscous oils and facilitates self-driven oil absorption through the synergistic photothermal conversion and magnetic properties of CZIF-67, respectively. After ten consecutive separation cycles, the aerogel consistently maintains its efficiency in oil/water separation, regardless of the employed method, whether gravity-driven or facilitated by a peristaltic pump. Notably, the PDMS@CZIF-67/CS aerogel manifests a high adsorption capacity for various emerging pollutants, specifically MPs, achieving an almost complete adsorption efficiency. This paper introduces an innovative, eco-friendly approach aimed at mitigating oil-contaminated wastewater and emerging pollutants, highlighting its potential for widespread application. [ABSTRACT FROM AUTHOR]

• Membranes are developed for simultaneous removal of organic contaminants and heavy metal ions. • The membranes are fabricated by blending Fe 3 O 4 @PDA nanoparticles in PES matrix via LIPS. • The Fe 3 O 4 @PDA nanoparticles blended in the membranes act as both catalysts and adsorbents. • The composite membranes exhibit both large permeability and high separation efficiency. Novel composite membranes are successfully developed for simultaneous adsorption of heavy metal ions and catalytic degradation of organic contaminants by blending polydopamine-coated ferroferric oxide (Fe 3 O 4 @PDA) nanoparticles in polyethersulfone (PES) matrix via liquid-induced phase separation (LIPS) method. The permeabilities of the as-fabricated composite membranes are significantly improved by introducing Fe 3 O 4 @PDA nanoparticles, because the hydrophilic coating on the surface of Fe 3 O 4 @PDA nanoparticles enables to generate more microporous structures between the PES matrix and nanoparticles during the LIPS process. The composite membrane containing 20 wt% Fe 3 O 4 @PDA nanoparticles shows water flux as high as 2640 L∙m−2∙h−1∙bar−1, which is six times larger than that of PES blank membrane. The composite membranes exhibit efficient and repeatable performances for simultaneous adsorptive removal of heavy metal ions and catalytic degradation of organic contaminants based on the mechanism of Fenton-like reaction. The proposed composite membranes with multifunction of simultaneous catalytic degradation of organic contaminants and adsorption of heavy metal ions provide a new pathway to deal with some hard-to-be-treated wastewaters from papermaking, leather, textile printing-dyeing industries, and so on. Furthermore, the proposed one-step strategy for fabricating composite membranes with both large permeability and high separation efficiency in this work is easy to be scaled up. [ABSTRACT FROM AUTHOR]

[Display omitted] • The water-dispersed polydopamine modified porous organic polymer nanoparticle (PDA@POP) was synthesized. • The PDA@POP based nanochannel membrane was prepared via dip coating and interfacial crosslinking method. • The PDA@POPM membrane exhibits both high water permeability and dye/salt selectivity. • The PDA@POPM membrane has good stability and anti-fouling property. Nanochannel membranes derived from porous nanomaterials are crucial for driving the development of advanced desalination and water treatment membranes. However, the practical application of polymer nanochannel membranes is halted by the tedious and complicated preparation and the lack of stability in aqueous service process. In this work, we synthesized a novel type of polydopamine modified imidazolium containing porous organic polymer nanoparticles (PDA@POP), which has good water dispersibility and interface adhesion capability. The PDA@POP aqueous dispersion solution was dip coated on the polysulfone ultrafiltration supporting layer, and the nanocoating was further crosslinked with 1,3,5-Benzenetricarboxylic chloride. The appropriate surface modification of POP nanoparticles with PDA enhances the interfacial interaction and maintains effective-aperture structure, leading to stiff and continuous nanochannels facilitating the water molecules and salt ions quickly transporting through the PDA@POPM membrane. As such, both the water permeability (∼57.0 L·m−2·h−1·bar−1) and dye/salt selectivity (>24) of PDA@POPM are improved 5–10 times higher than that of conventional polymer nanofiltration membranes. Meanwhile, the membrane exhibits good stability and anti-fouling property in long-term dye desalination process. This work provides a convenient and universal strategy to design and manufacture nanochannel membranes with high separation performance. [ABSTRACT FROM AUTHOR]

GO membranes cross-linked by copper ion and intercalated with tannic acid exhibit superior ionic sieving performance and aqueous stability. The fabrication strategy is novel and simple. [Display omitted] • GO membranes cross-linked by copper ion and tannic acid are successfully prepared. • The aqueous stability and permeance of membranes are improved simultaneously. • Outstanding membrane performance for K+/Mg2+ and K+/Cr3+ separation. • GO-Cu-TA 20 membrane exhibits a high K+ ion penetration rate of 0.75 mol m-2 h-1. • The membranes have great potentials in lithium extraction from salt lakes etc. Graphene oxide (GO) membranes have exhibited excellent molecular sieving properties in several areas, such as water treatment and gas separation, but unsatisfactory permeability and/or selectivity for ionic separation. Meanwhile, the instability of pure GO membranes in acidic solution has significantly impeded the ionic sieving applications. In this study, a kind of GO composite membranes (GO-Cu-TA a) with exceptional aqueous stability and superior ionic sieving properties are successfully prepared by employing a unique natural deposition strategy to introduce copper ions and tannic acid (TA). Based on the synergistic effect of the two cross-linking agents of copper ion and TA, the structural stability and ionic sieving performance of GO-Cu-TA a membranes are obviously enhanced. The resultant membrane with 20% TA loading displays excellent ionic sieving performance in a mixed solution containing K+, Mg2+ and Cr3+ three metal cations, and the selectivities of K+/Mg2+ and K+/Cr3+ are 46.43 and 185.32, respectively. Especially, the permeation rate of K+ ion reaches up to 0.75 mol m-2 h-1. Meanwhile, the ionic sieving property of such GO membranes possesses outstanding reusability and long-term stability. Such a membrane can also effectively separate mono-/multivalent metal cations from the mixed solution contained of the nine metal cations. The selectivities of monovalent/divalent metal cations (such as K+/Pb2+, K+/Ca2+, K+/Mg2+) are as high as 7.69–51.49, and those of monovalent/trivalent metal cations (such as K+/Fe3+, K+/Cr3+, K+/Al3+) are as high as 247.62–346.67. These results indicate that the GO-Cu-TA a membranes fabricated by the method of natural deposition strategy are expected to be used in the practical applications of lithium extraction from Salt Lake and wastewater purification, etc. [ABSTRACT FROM AUTHOR]

• This paper presents a comprehensive overview of technologies for GO membrane preparation. • Two mainstream ion separation mechanism of GO membrane is systematacially discussed. • Functional modifications applied to GO membranes are discussed, and their respective merits and limitations are critically evaluated. • The application of GO membrane in various membrane separation techniques is summarized. • The key issues for the imminent challenge faced by GO membranes in ion sieving and prospects for impending research are highlighted. Seawater salt ion sieving and rejection achieved through membrane separation is inevitable as the human development to obtain fresh water or pure salt. Recently, graphene oxide (GO) membrane with unique physicochemical properties and adjustable structure has unique advantages in seawater desalination. In this paper, we briefly review the development of the GO membranes for seawater salt ion sieving and rejection including the preparation process, ion sieving mechanism, and physical/chemical functional modification of the GO membranes. We compare the current research status of various membrane separation technologies in different application areas and identify potential future research directions. This article aims to offer researchers ideas for the preparation and application of GO membranes, with a focus on developing green and cost-effective manufacturing processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new strategy based on ion complexation for the regeneration of gas-phase mercury removal adsorbents was proposed. • The KCl solution had excellent elution effect on HgO on MnTi adsorbent. • The MnTi adsorbent could be well reused. MnTi adsorbent prepared by precipitation method was used to remove elemental mercury in pure nitrogen atmosphere, and TPD method was employed to investigate the mechanism of mercury elution from mercury-loaded MnTi adsorbent in KCl solution. In the gas-phase mercury adsorption process, the MnTi adsorbent removed mercury with a high efficiency of 50% under pure nitrogen atmosphere. The effects of stirring time, eluent concentration, and pH on Hg elution efficiency were evaluated in the liquid-phase Hg elution process. Mercury elution was assisted by adequate stirring time and eluent concentration. The pH value of the environment influenced mercury elution, with an acidic environment being more effective for mercury oxide elution. According to the experimental results, the highest mercury elution efficiency of 0.5 M KCl solution was 79%. The active chlorine produced during the elution process was valuable for reuse. The mercury removal performance of the reused MnTi adsorbent was not significantly different from that of the fresh adsorbent. The elution mechanism of HgO was also proposed, with the key link being the reaction of HgO(red) in solution with excess Cl− to form [HgCl 4 ]2− complexes, which then entered the liquid phase. It was possible to conclude that KCl solution had a high potential for mercury elution from mercury-carrying adsorbents and waste adsorbent reuse. [ABSTRACT FROM AUTHOR]