Desalination Applications Research Articles

Nitrogen-Doped Graphene Aerogel toward Efficient Solar Steam Generation: Synergistic Effects of Thermal Conductivity and Wettability.

Solar-driven interfacial evaporation technology is regarded as a promising strategy for global freshwater shortage owing to its green and sustainable desalination process. Graphene aerogel (GA) is widely utilized in the design of solar-driven steam generation systems due to its excellent photothermal conversion efficiency and broad spectral absorption. Given the significant impact of hydrophilicity and thermal insulation on the performance of evaporators, nitrogen doping in the graphene structure not only effectively enhances its wettability but also allows for moderate tuning of its thermal conductivity, thereby optimizing the overall performance of the evaporator. Therefore, graphene oxide (GO) and ethylenediamine were used to prepare nitrogen-doped graphene aerogel (NGA) via a one-step hydrothermal method. Experimental investigations and molecular dynamics (MD) simulations were employed to explore the effects of varying nitrogen-doping concentrations on the thermal conductivity and wettability of NGA. The results revealed that as the nitrogen-doping concentration increased, the aerogel exhibited enhanced wettability, while the thermal conductivity initially decreased and then increased. This phenomenon is attributed to the fact that improved wettability can hinder heat convection, resulting in reduced heat transfer efficiency. However, further enhancement in wettability reduces the solid-liquid interfacial thermal resistance, thereby boosting heat transfer performance. Consequently, NGA-2, with an optimal nitrogen-doping concentration, demonstrated superior evaporation performance, achieving a high evaporation rate of 1.64 kg m-2 h-1 and an outstanding evaporation efficiency of 92.2% under one-sun irradiation. This study highlights the improved performance of solar evaporators through the synergistic effects of heat and mass transfer, underscoring their significant potential in seawater desalination applications.

Orientation-Dependent Anisotropic Desalination by Assembled Zeolite Nanotube Membranes.

Porous nanomaterials have shown great promise in many desalination applications. Zeolite nanotubes, featuring abundant but inhomogeneous nanopores on their surface, have been recently synthesized in experiments; however, their capacity for desalination is not yet understood. In this work, we use molecular dynamics simulations to investigate the capability of assembled zeolite nanotube membranes to perform in desalination applications due to their inherent multiscale porous properties. Two different membrane assemblies are examined to determine the effect of membrane orientation on desalination performance. Interestingly, we find that zeolite nanotube membranes present anisotropic desalination behavior, which is directly dependent on the assembled orientation of the zeolite nanotubes. Specifically, directing the transport through the axial channels of the nanotubes results in a water permeability of 59.8 L/cm2/day/MPa and 88% ion rejection. However, when the membrane is rotated 90° and the flow is directed perpendicular to the tube axis, the permeability drops to 22.3 L/cm2/day/MPa, but 100% ion rejection is achieved. This difference is attributed to the multiscale pore dimensions of the zeolite nanotube; that is, they possess large pores (a diameter of 3 nm) along the axial channel direction, but smaller pores (a diameter of 0.25 nm) along the direction perpendicular to the tube axis. The ion rejection capabilities are further verified by quantifying the free energy barriers to transport obtained via umbrella sampling simulations. Therefore, our findings demonstrate the orientation-dependent, anisotropic desalination performance in assembled zeolite nanotube membranes for the first time, which could be useful in designing future advanced desalination membranes.

Bilayer nanographene reveals halide permeation through a benzene hole.

Graphene is a single-layered sp2-hybridized carbon allotrope, which is impermeable to all atomic entities other than hydrogen1,2. The introduction of defects allows selective gas permeation3-5; efforts have been made to control the size of these defects for higher selectivity6-9. Permeation of entities other than gases, such as ions10,11, is of fundamental scientific interest because of its potential application in desalination, detection and purification12-16. However, a precise experimental observation of halide permeation hasso far remained unknown11,15-18. Here we show halide permeation through a single benzene-sized defect in a molecular nanographene. Using supramolecular principles of self-aggregation, we created a stable bilayer of the nanographene19-23. As the cavity in the bilayer nanographene could be accessed only by two angstrom-sized windows, any halide that gets trapped inside the cavity has to permeate through the single benzene hole. Our experiments reveal the permeability of fluoride, chloride and bromide through a single benzene hole, whereas iodide is impermeable. Evidence for high permeation of chloride across single-layer nanographene and selective halide binding in a bilayer nanographene provides promise for the use of single benzene defects in graphene for artificial halide receptors24,25, as filtration membranes26 and further to create multilayer artificial chloride channels.

Advances in cellulose materials for interfacial water evaporation and their applications in seawater desalination

Advances in cellulose materials for interfacial water evaporation and their applications in seawater desalination

Sustainable solar-powered seawater desalination enabled by phosphorene-decorated watermelon-like phase-change microcapsules

Solar-powered interfacial evaporation is considered as an emerging innovative technology for seawater desalination; however, it suffers from insufficient evaporation efficiency under intermittent solar irradiation. Aiming at realizing sustainable solar-powered seawater desalination for clean water production, we have designed a new type of watermelon-like phase-change microcapsules as a photothermal absorbent material for a solar interfacial evaporator. This type of phase-change microcapsules was prepared through rational layer-by-layer microencapsulation with a ZrO2 nanoparticle-containing n-docosane core as a phase-change material (PCM) for solar photothermal harvest and prompt thermal response, a ZrO2 shell for the leakage prevention of the molten n-docosane core, and a polydopamine coating layer together with its surface-decorated phosphorene nanoflakes for high-efficient sunlight absorption and fast water transportation. The resultant microcapsules are featured by a watermelon-like microstructure as confirmed by transmission electron and scanning electron microscopy. They also exhibit a high light absorption efficiency of 84.95 %, a high latent heat capacity of 146.2 J g−1, and good wettability. Equipped with the watermelon-like phase-change microcapsules, the developed solar interfacial evaporator obtained an evaporation rate of 3.09 kg m−2 h−1 under one-sun illumination for seawater desalination. The PCM core within the microcapsules can store solar photothermal energy as latent heat under sufficient solar irradiation and then release it under evaporation conditions without sunlight illumination, thus enhancing the water evaporation efficiency. This enables the developed evaporator to increase its total evaporation mass by 31.5 % on a cloudy day in comparison with the conversional solar evaporator without a PCM, indicating a remarkable enhancement in the evaporation performance under intermittent solar irradiation. The developed solar interfacial evaporator exhibits great potential for application in sustainable solar-powered seawater desalination.

Monte Carlo simulation of ultrafast water flow in nanotubes

Water transport through nanostructures, particularly nanotubes, is a critical area of study with significant implications for filtration, desalination, and energy-related applications. This research investigates the dynamics of water molecules within nanotubes, focusing on the mechanisms that enable ultrafast transport along the nanotube axis. By employing Monte Carlo simulations, the effects of key parameters such as lattice spacing, friction, and molecular interactions on water flux are systematically analyzed. Furthermore, a theoretical model is developed to elucidate the underlying principles of water flow, highlighting the role of molecular interactions and external periodic potentials in driving efficient transport. The findings contribute to a deeper understanding of nanoscale water dynamics and offer valuable insights for optimizing nanotube-based systems in advanced technological applications.

A PDA@ZIF-8-Incorporated PMIA TFN-FO Membrane for Seawater Desalination: Improving Water Flux and Anti-Fouling Performance.

Forward osmosis (FO) technology, known for its minimal energy requirements, excellent resistance to fouling, and significant commercial potential, shows enormous promise in the development of sustainable technologies, especially with regard to seawater desalination and wastewater. In this study, we improved the performance of the FO membrane in terms of its mechanical strength and hydrophilic properties. Generally, the water flux (Jw) of polyisophenylbenzamide (PMIA) thin-film composite (TFC)-FO membranes is still inadequate for industrial applications. Here, hydrophilic polydopamine (PDA)@ zeolitic imidazolate frameworks-8 (ZIF-8) nanomaterials and their integration into PMIA membranes using the interfacial polymerization (IP) method were investigated. The impact of PDA@ZIF-8 on membrane performance in both pressure-retarded osmosis (PRO) and forward osmosis (FO) modes was analyzed. The durability and fouling resistance of these membranes were evaluated over the long term. When the amount of ZIF-8@PDA incorporated in the membrane reached 0.05 wt% in the aqueous phase in the IP reaction, the Jw values for the PRO mode and FO mode were 12.09 LMH and 11.10 LMH, respectively. The reverse salt flux (Js)/Jw values for both modes decreased from 0.75 and 0.80 to 0.33 and 0.35, respectively. At the same time, the PRO and FO modes' properties were stable in a 15 h test. The incorporation of PDA@ZIF-8 facilitated the formation of water channels within the nanoparticle pores. Furthermore, the Js/Jw ratio decreased significantly, and the FO membranes containing PDA@ZIF-8 exhibited high flux recovery rates and superior resistance to membrane fouling. Therefore, PDA@ZIF-8-modified FO membranes have the potential for use in industrial applications in seawater desalination.

Mitigating biofouling of polyamide thin-film composite RO membrane modified with AgNPs and pSBMA: an evaluation close to the actual SWRO desalination application scenario

ABSTRACT The long-term sustainability of beneficial effects resulting from the modification of polyamide thin-film composite (PATFC) membranes with zwitterionic poly(sulfobetaine methacrylate) (pSBMA) and silver nanoparticles (AgNPs) in real-world application scenarios remains uncertain. This study used response surface methodology and innovative anti-biofouling evaluation method to optimize the conditions for AgNP- and pSBMA-co-modified PATFC membranes, with reverse osmosis seawater desalination as the test application scenario. A 180-day continuous seawater treatment test was conducted to evaluate the long-term sustainability of anti-biofouling resistance. Results indicated that loading AgNPs before grafting pSBMA enhanced their stability during use and cleaning. Co-modification under optimal conditions led to a 6.3% improvement in membrane flux reduction over long-term operation. The effect of AgNPs was significant for 30 days, while pSBMA remained effective until the end of the test. Water contact angle measurements, confocal laser scanning microscopy, and quorum sensing signal molecule analysis revealed anti-bioflouling improvements due to the hydration layer and electrostatic barrier from pSBMA, as well as quorum sensing inhibition and disinfection from AgNPs. These findings confirm the discount effectiveness and feasibility of the pSBMA and AgNPs co-modification technique during long working time, offering valuable insights into modification operations and anti-biofouling mechanisms.

Efficient Light to Heat Conversion in Sb2Se3 Nanorods and the Role of Macro-channel Imprinted Sb2Se3 Loaded Hybrid Membrane for Superior Desalination Performance.

This report validates Sb2Se3 nanorods (NRs) as a potential contender for solar thermal heat generation. The water droplet experiment shows Sb2Se3's light-to-heat conversion efficiency as ≈57.8% for red (671nm), 58% for green (532nm) lasers. Following this PVDF(M)/ Sb2Se3 NRs hybrid membranes for solar desalination reached ≈59°C in 15 minutes of illumination. The heat generation is dominated by an electron/hole-acoustic phonon scattering mechanism. Despite having superior visNIR absorption and heat localization in Sb2Se3 NRs, the hybrid membranes show an evaporation rate of 1.72 kg m-2h-1 only, even if mass loading is increased. The hydrophobic Sb2Se3 NRs layer restricts water diffusion to hot zones, reducing solar evaporation efficiency. A novel macrochannel imprinting strategy in hybrid membranes speeds up water transport to the hot zone. Consequently, optimized macrochannel membranes achieve ≈2.37kgm-2h-1 mass loss and 148% solar evaporation efficiency under a 1000Wm-2 mercury vapor lamp. Therefore, imprinting macro-channel can be a possible strategy, addressing the hydrophobic materials in desalination applications which can be expanded in other similar materials. Moreover, its outdoor sunlight application achieves impressive solar evaporation efficiency (≈108%). The steam generated effectively removes heavy metals, meeting World Health Organization (WHO) potable water standards.

Calla lily-inspired 3D evaporator: A dual interface design for enhanced solar water evaporation

Due to the exponential growth of the global population, groundwater resources have long been insufficient to meet the escalating demand for potable water. In recent years, interfacial solar stream generation (ISSG) technology has emerged as a pivotal approach in generating clean water. The paramount performance factors of solar thermal evaporators encompass their exceptional light absorption capacity, efficient water transport, and effective thermal management. Among these factors, the 3D interface evaporator stands out due to its inherent advantages and ingenious structural design that enhances overall performance. In this study, the structure of calla lilies was used as inspiration, we propose a novel design featuring a 3D inverted conical double-sided evaporator (3D-ASIE) which effectively traps sunlight within its core, thereby augmenting light absorption capabilities while simultaneously forming a dual-evaporation interface. The inverted conical structure comprises two cellulose/TiN aerogel films with superior light absorption and heat insulation properties along with a polytetrafluoroethylene (PTFE) hydrophilic film that is skillfully bent and assembled together. To ensure continuous water supply during evaporation, the tail end of the hydrophilic membrane is immersed in water. During interfacial evaporation process, activation of the outer photothermal layer of our 3D-ASIE facilitates steam diffusion along both inner and outer surfaces of the inverted cone structure concurrently resulting in an impressive dual-evaporative effect. Under sunlight intensity level at 1 kW m−2, our 3D-ASIE exhibits remarkable performance with an evaporation flux reaching up to 2.97 kg m−2 h−1 alongside an efficiency as high as 94.7 %, thus demonstrating immense potential for large-scale solar desalination applications.

Synergistic photothermal enhancement of the antibacterial activity of fibroin hydrogel by dual-directional crosslink strategy for efficient solar steam generation

Silk fibroin (SF) has attracted wide attention due to its excellent biocompatibility and versatile adjustability. The regeneration and reutilization of silk fibroin can efficiently utilize waste cocoons and silk. However, the regenerated SF hydrogels suffer from inadequate mechanical properties and lack inherent antibacterial capabilities, limiting their application in seawater desalination. This study achieved a novel hydrogel (STS@Fe) with photothermal antimicrobial activity, good mechanical property, and excellent durability using a green dual-directional crosslink and meso-reconstruction strategy. The metal-phenolic networks (MPN) were synthesized utilizing the natural plant polyphenol tannic acid (TA) and Fe3O4 nanoparticles. This research incorporated MPN into dissolved and regenerated silk fibroin and sodium alginate solution, enhanced mechanical properties through cryogenic salt precipitation, and prepared STS@Fe hydrogel. The inherent photothermal properties of Fe3O4 nanoparticles and TA complex, coupled with their synergistic effect under near-infrared radiation, can confer excellent photothermal-enhanced antibacterial activity to the fibroin hydrogel. The tensile strength of STS@Fe hydrogel is enhanced 31 times than that of traditional fibroin hydrogel, and its evaporation rate is 4.77 times higher than that of pure water evaporation. The hydrogel has an efficient seawater desalination rate and outstanding antibacterial properties in real seawater conditions. Moreover, The STS@Fe shows effective treatment capabilities for dyeing wastewater and oily saline water.

Cyrene-Enabled Green Electrospinning of Nanofibrous Graphene-Based Membranes for Water Desalination via Membrane Distillation.

High-performance and sustainable membranes for water desalination applications are crucial to address the growing global demand for clean water. Concurrently, electrospinning has emerged as a versatile manufacturing method for fabricating nanofibrous membranes for membrane distillation. However, widespread adoption of electrospinning for processing water-insoluble polymers, such as fluoropolymers, is hindered by the reliance on hazardous organic solvents during production. Moreover, restrictions on industrial solvents are tightening as environmental regulations demand greener alternatives. This critical challenge is addressed here by demonstrating, for the first time, the fabrication of nanofibrous electrospun membranes of PVDF-HFP, poly(vinylidene fluoride)-co-hexafluoropropylene using a renewable, environment- and user-friendly solvent system containing Cyrene (dihydrolevoglucosenone), dimethyl sulfoxide, and dimethyl carbonate. The same solvent system was further used to produce nanocomposite graphene oxide (GO) and graphene nanoplatelet (GNP)-containing nanofibrous electrospun membranes. When tested for water desalination via membrane distillation, these membranes either outperformed or matched the performance of those produced with hazardous organic solvents, achieving salt rejection rates of >99.84% and long-term stability. The economic viability of the green solvent system was further validated through Monte Carlo simulations. This work demonstrates the potential to move fluoropolymer electrospinning from dimethylformamide-based systems to greener alternatives, enabling the consistent production of high-quality nanofibrous membranes. These findings pave the way for more sustainable manufacturing practices in membrane technology, specifically for water desalination via membrane distillation.

Structural optimization of separation layer and porous PES substrate for enhanced pervaporation desalination performance

Pervaporation membranes with water-selective properties hold great potential for desalination and brine concentration applications. In this study, a modified PES porous membrane with smaller pore sizes and enhanced interfacial support was used as the substrate. Ultrathin selective layers were fabricated on its surface via atomized spray coating, resulting in high-performance pervaporation membranes for desalination analysis. The study compares the effects of PVA and PEI on membrane performance under different crosslinking systems. At 82 °C, using a 3.5 wt.% sodium chloride solution, the PES composite membrane with a PEI/SPTA selective layer achieved a maximum flux of 180.35 ± 13.8 kg m-² h⁻¹, with a salt rejection rate of 99.97% ± 0.2. Even at a higher brine concentration of 20 wt.%, the membrane maintained a flux of 49.77 ± 7.3 kg m-² h⁻¹ at 72 °C. The membrane's high salt rejection and stable performance under complex operating conditions demonstrate that pervaporation composite membranes prepared with low-surface-porosity substrates offer enhanced cycle stability and industrial potential in real-world desalination and concentration applications.

Electrochemical Synthesis with Flow Electrodes: An Innovative Process Concept from Biobased Ressources to Polymers

Electrochemical production of chemicals aims to enable the direct use of renewable electricity and sustainable resources such as biomass. A promising biobased product is the polymer furan-2,5-dicarboxylate (PEF). This polymer is synthesized from hemicellulosic biomass via the intermediates 5-hydroxymethylfurfural (HMF) and 2,5-furandicarboxylic acid (FDCA). The synthesis step from HMF to FDCA can take place via an electrochemical route, which is focus of this work.The main limitation of electrochemical processes is restricting the active area to the electrode surface. We aim to overcome this limitation by suspending catalyst-coated particles in the electrolyte - a so-called slurry electrode or flow electrode. Flow electrodes have already successfully found applications in desalination or energy storage, but we want to show that electrochemical synthesis can also benefit from flow electrodes. This is why, in this work, we show that the electrochemical production of FDCA with flow electrodes is possible. For that we deposit the catalyst NiOOH/Ni(OH)2 on a particle substrate. The coated particles, suspended in 0.1M KOH solution, compose the flow electrode. The flow electrode flows through an electrochemical flow cell, where the catalyst coated particles contact the external current supply at the anodic current collector. This current collectors consists of pure nickel, which does not catalyze the electrochemical oxidation of HMF to FDCA. Our results show that the process concept works, and the synthesis of FDCA happens on the particles within the flow electrode.We investigated the impact of the particle substrate on the reaction. For that we coated the catalyst on different particle substrates (graphite, glass, and nickel) and used them in a flow electrode. The highest conversion can be achieved with graphite particles, whereas the reaction performs significantly worse on glass particles.We also explore the reaction mechanisms taking place. The results indicate that the reaction mechanism covers two steps: The catalytic oxidation of HMF to FDCA and the electrochemical catalyst regeneration. These steps in the reaction mechanism do not necessarily have to take place simultaneously. The particles can be pre-charged by applying electrical current without reactant HMF in the solution. When HMF is added after the pre-charging step, the catalytic conversion to HMF increases compared to non-pre-charged particles.Our findings have significant implications for the practical application of the FDCA production process. Flow electrodes allow the process to operate even with fluctuating substrate concentrations. Without HMF, the particles can be charged, converting the inactive nickel species to the active one. Once HMF becomes available again, the particles' catalytic capacity can convert it to FDCA directly. This dynamic operation of the process enhances its efficiency and makes it more adaptable to real-world conditions, potentially paving the way for its large-scale implementation.

Direct Formation of Todorokite Mn Oxide Via Electrodeposition

Todorokite, a manganese oxide with a 3 × 3 tunnel structure (~1 nm), has attracted interest for its potential application in energy storage, desalination, sensor, and catalyst, owing to its reversible ion exchange capacity and catalytic activity. However, conventional synthesis of todorokite involves a time- and energy consuming three-step process: (1) precipitation of a layered Mn oxide, (2) intercalation of Mg2+ into the layer, and (3) transformation to todorokite via hydrothermal reaction. In this study, we propose a novel method for the direct formation of todorokite within 30 minutes using 1 M MgCl2 electrolyte with Mn2+(aq) at pH 8.5 via electrodeposition. Our electrochemical approach enabled the formation of todorokite by stabilizing structured Mn(III), which induces Jahn-Teller distortion and structural rearrangement to form tunnel, through precise adjustment of pH and concentration of Mg2+. Notably, we confirmed, through computational calculations and experimental results, the significant changes in Mn(III) within Mn oxides approximately pH 7.4, as well as range of Mg(OH)+ concentrations that stabilize Mn(III) for todorokite formation. Our electrochemically mediated method not only facilitates the synthesis of todorokite but also provides specific insights into the mechanisms of its direct formation.

Robust and Antifouling Composite Hydrogels Enhanced by Directional Freeze-Casting and Salting-Out for Highly Efficient Solar Evaporation.

Hydrogels have been identified as a promising material platform for solar-driven interfacial evaporation. However, designing durable hydrogel solar evaporators that can combine effective photothermal conversion, superior water transport, salt resistance, and robust mechanical properties to ensure stable and efficient evaporation remains a significant challenge. Herein, a robust and antifouling hydrogel-based solar evaporator composed of poly(vinyl alcohol), sodium alginate, and MXene is successfully constructed through directional freeze-casting and salting-out processes. The directional freeze-casting aids in forming vertically aligned, well-interconnected channels within the hydrogel that facilitate rapid upward water transfer and effective salt ion discharging, while the optimized salting-out process promotes the cross-linking of polymer chains, creating a sponge-like porous structure that enhances key mechanical properties such as high elasticity and exceptional flexibility. The developed hydrogel evaporator achieves an impressive evaporation rate of 2.53 kg m-2 h-1 with an energy efficiency of 93%, as well as excellent salt resistance and long-term evaporation stability even when desalinating high-concentration brines. These exceptional characteristics make this composite hydrogel evaporator highly suitable for practical applications in seawater desalination and wastewater purification.

Conformal Conductive Polymer Deposition on Carbon Nanotube Forests

Carbon nanotube (CNT) forests are highly conductive and possess a large surface area, making them promising as electrode support materials for electrochemical applications including energy storage and water desalination. However, these forests often suffer from mechanical collapse when exposed to liquids, limiting their effectiveness in wet environments. In this study, we explore the use of vapor-phase oxidative molecular layer deposition (oMLD) to deposit thin, redox-active polymer films onto CNT forests to enhance their mechanical and electrochemical properties. We evaluate the mechanical behavior of the polymer-coated CNT forests using nanoindentation compression tests and solvent evaporation tests. The modulus and buckling stress of the forests increase with the thickness of the polymer coating, indicating enhanced mechanical strength conferred by the oMLD process. Furthermore, solvent evaporation tests demonstrate that the morphology of the polymer-coated CNT forests remains undisturbed by surface tension forces, in contrast to uncoated CNT forests which collapse and densify. This preservation of morphology underscores the effectiveness of the polymer coating in protecting the CNT forests from structural degradation in liquid environments. To gain deeper insights, finite element simulations analyze the mechanical properties of both coated and uncoated CNT forests. The simulations reveal that the increase in buckling load scales with the bending stiffness of individual CNTs and their coatings, highlighting the synergistic effect of the polymer coating on the overall forest structure. Finally, electrochemical characterization in aqueous electrolyte indicates an increase in charge capacity with polymer thickness for thin films, and a decrease in charge capacity at high film thicknesses arising from restricted pore volume. This work indicates that oMLD polymer coatings enhance the mechanical strength and electrochemical activity of CNT-based substrates. The findings from this study contribute to the development of more efficient and durable CNT-based electrodes for water desalination and energy storage applications.

High-performance polyester composite nanofiltration membrane fabricated by interfacial polymerization of ribitol and trimesoyl chloride: Dye desalination performance and mechanisms

A loose nanofiltration (LNF) membrane with high permeance and excellent dye/salt selectivity is highly desirable for dye/salts recovery from textile wastewater. Herein, commercial and green ribitol (RT) was employed to fabricate the LNF membrane for dye desalination. The hydroxyl in the RT reacted with acyl chloride under the catalysis of sodium hydroxide, forming a polyester film structured with microspheres, negative charge, and hydrophilic networks. The resultant RT-M membrane possessed a smooth and thin active layer with numerous polar groups. The dye desalination performance of the RT-M membrane was tailored by controlling various IP fabrication conditions. The optimized membrane (RT-M1.0) had superior water permeance (100.3 L m−2h−1 bar−1) and satisfactory CR/Na2SO4 selectivity (281.3). Additionally, the RT-M membrane had favorable stability and antifouling properties, demonstrating excellent potential for application in dye desalination. Therefore, a novel approach for fabricating membranes with outstanding dye desalination properties by using RT was proposed to achieve resource recycling.

RuO2−MXene nanocomposite coated on bio-degradable loofah sponge for enhanced rate of evaporation in interfacial solar desalination

Worldwide pure drinkable and usable water demand is increasing such as in the regions of Middle East, North Africa, and South Asia majority of the population are facing extreme water scarcity. Among numerous types of solar desalination technologies, interfacial solar steam generation (ISSG) has the potential practical applications on wastewater treatments, power generation, sterilization, and soil remediation beyond the application of only on desalination. In this research, MXene@RuO2 nanocomposite coated on bio-degradable luffa sponge is harnessed where the synthesis of MXene-RuO2@LS is done hydrothermally. As ruthenium oxide (RuO2) is a metal oxide with having the capability of ensuring effective surface area by preventing the restacking of MXene which happens due to their inherently high interfacial van der Waals interactions and surface energy. Bio-degradable luffa sponge is the best example of an evaporator with large pore spaces and rigid structure. As a result, the novel MXene-RuO2@LS absorber exhibited the rate of evaporation about 1.5 Kgm−2h−1 under 1 sun illumination for about 1 h. Furthermore, the prepared sample achieved the total energy consumption of 90.85 % with total heat loss of only 9.15 %. UV–Vis characterization was performed with improved absorptivity of 1.2, enhancement of transmittance by FTIR analysis of about 95 %, XRD analysis, SEM image analysis and water contact angle are evaluated as well. In addition, the collected desalinated water is tested where noticeable reduction of major ion concentrations and salinity achieved. All these enhanced results indicate the practical application of interfacial solar desalination.

Durable TiO2@Cu-alginate hydrogel membrane with rapid in-situ cleaning for high-performance dye desalination applications

Nanofiltration (NF) membrane filtration has garnered significant attention for the desalination of high-value-added molecules due to its exceptional selective separation performance. In this study, CuCaAlg/TiO2 membranes were synthesized by physically incorporating nanoparticles into the natural alginate polymer network through dual cross-linking. The synthesis process was rapid, straightforward, and environmentally friendly, with no organic waste discharge. The interaction between rigid inorganic nanofillers and polymer networks not only enhances the mechanical strength of the hydrogel but also modulates the degree of topological defects within the membrane structure. This modulation facilitates overcoming the selective separation-permeation trade-off effect in the separation process. The resulting membrane exhibited outstanding dye/salt separation performance, including high permeability and efficient dye/salt selectivity separation. Additionally, the membrane demonstrated excellent hydrophilicity, swelling resistance, and anti-fouling properties. Furthermore, combined with a simple cleaning strategy (UV-H2O2-cross flow filtration), this composite functional membrane enabled rapid in-situ cleaning in high-concentration dye application scenarios. Such cleaning procedures contribute to maintaining the stability of the hydrogel membrane during dye desalination and separation applications. We anticipate that this composite membrane holds great promise for resource treatment of dye wastewater across various scenarios.