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Nanoplastics (NPs) are emerging pollutants that are effectively adsorbed by magnetic biochar (MBC). However, in complex aquatic environments, other carbon substances such as dissolved organic matter (DOM) considerably affect the microinterface interactions between NPs and MBC, but the interaction mechanism remain unclear. This research investigates the effects of different DOM types—fulvic acid (FA) and humic acid (HA)—on the adsorption behavior of polystyrene NPs (PSNPs) by MBC. Both FA and HA were found to decrease the adsorption affinity of MBC for PSNPs, with reductions of 80.3 % and 53.2 %, respectively, compared to systems without DOM. It was inferred that MBC preferentially complexes and forms ligands with the aromatic and hydrophobic substances in the FA structure, inhibiting the attachment of PSNPs. Environmental factors, such as ionic strength and high-valence cations could reduce the adverse effects of DOM on MBC–PSNP interaction via ion bridging in multi-solute systems. The type of DOM also influences the sequential arrangement of functional groups during the adsorption of PSNPs by MBC. In different water media, seawater exhibited minimal impact on the interactions among PSNPs, MBC and DOM. Overall, these findings provide new insights into the fate and transport of PSNPs in multi-solute systems. [Display omitted] • DOM inhibits the attachment of nanoplastics (NPs) by magnetic biochar (MBC). • The inhibitory effect of fulvic acid was stronger than that of humic acid. • Ionic strength and high-valence cations reduced the DOM inhibitory. • DOM significantly increased the electrostatic repulsion between NPs and MBC. [ABSTRACT FROM AUTHOR]

Solar evaporators not only convert absorbed solar energy into heat and steam but also generate osmotic energy. Through meticulous interface engineering and water transmission strategies, a photothermal gel consisting of MXene, liquid metal, and polyvinyl alcohol was applied to cotton thread surfaces in this study, resulting in photothermal hydrogel cotton threads with strong hydrophilicity and excellent light absorption rates (> 95 %). These cotton threads were then arranged into an arc, with one end immersed in low-salinity sea water and the other in high-salinity brine, creating a solar evaporator setup. By combining a high-salinity brine collector with a permeation tank equipped with electrodes, commercial Nafion membranes, and simulated saltwater, a series of solar-evaporator-based permeation energy generators was established. The solar evaporator achieved a high evaporation efficiency of up to 4.62 kg m−2 h−1 when exposed to 1 kW m−2 of sunshine, producing high-salinity brine and stable water vapor without the formation of surface-bound solid salt crystals during extended use. The permeation generator demonstrated a current of 160 μA and maximum power density of 1.17 W m−2 after 11 h of illumination. This combination of solar evaporators and osmotic energy generation offers a novel approach to seawater desalination and permeable energy generation. • A novel Photothermal gel composed of MXene, liquid metal and polyvinyl alcohol. • A unique combination of solar desalination evaporator and osmotic energy generator. • The higher evaporation efficiency reaches up to 4.62 kg m−2 h−1. • The evaporator exhibits a continuous solar desalination capacity. • The osmotic energy generator demonstrates remarkable power density (1.17 W/m2). [ABSTRACT FROM AUTHOR]

The present study demonstrates the feasibility of gas hydrate technology for effective desalination of salt water without requiring pre- or post-treatment. The research highlights two main aspects: the thermodynamic and comparative kinetic properties of hydrofluorocarbon (HFC) gases, and the novel concept of hydrate pelletization enhanced by an induced pellet melting procedure. The thermodynamic viability of HFC gases such as HFC-125a, HFC-134a, and HFC-152a for hydrate formation in both saline and non-saline conditions is underscored. For the first time, a comparative analysis of the gas uptake kinetics for these three gases is presented under 0, 3.5, and 8.0 wt% NaCl conditions. Results indicate that HFC-134a and HFC-152a exhibit rapid gas uptake kinetics, while HFC-125a shows sluggish kinetics, attributed to the effective pressure driving force and subcooling temperature. Regardless of the guest gas, the chosen experimental conditions achieved salt removal efficiency of ~70 % in 3.5 wt% NaCl and ~ 75 % in 8.0 wt% NaCl. The novel induced hydrate pellet melting approach significantly improved salt removal efficiency, exhibiting a nonlinear behavior where the rate of salt removal efficiency increases asymptotically as more hydrate melts. New insights into salt distribution within the hydrate pellet reveal that the core contains higher salinity, than the outer layer. • Gas hydrate technology desalinates seawater efficiently without the need for pre- or post-treatment processes. • First comparative analysis of gas uptake kinetics for HFC-125a, HFC-134a, and HFC-152a at varying salinity levels. • Hydrate-based desalination removes ~70 % salt in 3.5 wt% NaCl and ~75 % in 8.0 wt% NaCl in a single-stage process. • A novel hydrate pelletization and induced melting method enhance salt removal to ~95 % and ~97 % for 3.5 and 8.0 wt% NaCl. • Mechanical compaction during pelletization creates a higher salt concentration in the core than in the outer layers. [ABSTRACT FROM AUTHOR]

Environmentally friendly and efficient solar-driven interfacial evaporation (SDIE) has been increasingly applied to seawater desalination, and the easy-to-operate electrospinning technology has attracted more and more attention. However, photothermal materials such as MXene are often combined with polymers suitable for spinning through ordinary blending. The inherent difficult dispersion of it may lead to the instability of spinning and decrease the performance of evaporators, further hindering their production and application. To address these challenges, this work designs a covalent bonding PVDF@MXene composite as the spinning raw material. Using the electrospinning technology, the high-efficiency membrane-based evaporator with well-dispersed internal materials and strong homogeneity is successfully fabricated. The membrane performance is optimal when the MXene content is 25 %, achieving an evaporation rate of 1.88 kg·m−2·h−1 and an efficiency of 94.06 % under one sun. Besides, it exhibits remarkable salt resistance, maintaining an evaporation rate of 1.81 kg·m−2·h−1 even at the salinity of up to 20 wt%. More importantly, the membrane can be immersed in oxidative reagents for 24 h without degradation or reduced performance, demonstrating its good environmental stability. Overall, this research not only provides a rational idea for addressing the dispersion issue of MXene, but also presents a potential solution to deal with the global freshwater shortage emergency. • PVDF@MXene composite linked by covalent bond was prepared for electrospinning. • The membranes with strong homogeneity were spun using electrospinning technique. • The membrane evaporation rate reached 1.88 kg·m−2·h−1 when its MXene content was 25 %. [ABSTRACT FROM AUTHOR]

Free-piston batch RO achieves excellent energy efficiency at high recovery, but current systems have outputs <25 m3/day. Designing larger systems poses challenges like designing an appropriate work exchanger and optimizing membrane arrangements in series and/or parallel. This study calibrates a batch RO model against brackish and seawater experiments up to 112 bar and uses the model to predict performance on scale-up. Modelling up to 6 membranes in series predicts SEC of 1.11–1.5 kWh/m3 at recirculation flow Q r / Q f = 4 with brackish water, with SEC becoming more sensitive to Q r / Q f as the number of membranes increases. Using a 500-L work exchanger, a batch RO system with twelve 8-in. membranes is designed. For brackish water (3000 mg/L) this system gives outputs of 165 and 128 m3/day with SEC of 0.69 and 1.19 kWh/m3 at recoveries of 0.93–0.97 with low- and high-pressure RO membranes, respectively - representing SEC reductions of 33 and 45 % compared to semi-batch RO. For seawater, it gives 105 m3/day with SEC of 2.37 kWh/m3 at recovery of 0.66. High-permeability membranes would significantly enhance batch RO performance; for example, increasing permeability from 0.8 to 2 L/m2/h/bar would boost output to 320 and 207 m3/day in brackish and seawater desalination respectively. [Display omitted] • Detailed model validation using brackish and seawater experiments up to 112 bar • Batch RO scale-up: 12 membranes (N S = 4 and N P = 3) with a batch volume of 500 L • 165 and 105 m3/day output with brackish and seawater, respectively • SEC of 1.2 and 2.4 kWh/m3 at r = 0.97 and 0.66 with brackish and seawater at scale • Improved permeability can nearly double output. [ABSTRACT FROM AUTHOR]

The economic challenges arising from resource depletion and uneven distribution of Mg in land reserves have spurred interest in technologies for Mg extraction from seawater. Thus, this study introduces a novel method to recover high-purity magnesium carbonate, specifically hydromagnesite, from seawater through carbonation using Ca(OH)₂ as an alkali source. A significant achievement of this method is the production of high-purity hydromagnesite despite the presence of large amounts of Ca, realized only through carbonation without the need for expensive additives such as NaOH. Experimental results reveal that the Ca(OH)₂ content predominantly influences the Mg dissolution efficiency during carbonation and the overall Mg recovery rate. Maximizing the efficiency of this technology relies on using an appropriate amount of Ca(OH)₂. Notably, the appropriate amount of OH− supply enhances CO₂ dissolution, facilitating Mg dissolution. Conversely, an excess of Ca(OH)₂ impedes Mg dissolution. The overall Mg recovery rate reaches a peak of 67 %, enabling the recovery of 3.4 kg of hydromagnesite from one ton of seawater. The findings highlight the effectiveness of the proposed technology as a promising and cost-effective method for extracting high-purity Mg from seawater, utilizing Ca(OH) 2 , previously considered an impurity, as a cost-effective alkali source. • Recovered high-purity hydromagnesite from seawater via carbonation using Ca(OH) 2 • Used Ca(OH)₂, previously deemed an impurity, as a cost-effective alkali • Optimal amounts of Ca(OH)₂ enhanced Mg dissolution but excess content inhibited it • Mg recovery peaked at 67 %, yielding 3.4 kg hydromagnesite per ton of seawater [ABSTRACT FROM AUTHOR]

Uranium is the basic ingredient for nuclear energy production, but its terrestrial resources are limited. The efficient extraction of uranium from natural seawater can greatly alleviate the current shortage of uranium resources. Herein, biomass material collagen fibers (CFs) were grafted by hyperbranched polyethyleneimine (HPEI) and amidoxime (AO) groups, and a novel anti-fouling uranium extraction adsorbent (CFs-PEI-AO) was successfully prepared by the chemical cross-linking method. The construction of molecular-level uranyl-specific nano-pocket through hydrogen-bond interaction between amino and amidoxime groups provided efficient extraction and ultra-high selectivity to uranium. This fibrous adsorbent displayed a remarkable uranium adsorption capacity of 561.80 mg g−1, with a notable K d value (4.57 × 105 mL g−1) in co-existing ions solution. In addition, the Schiff base structure formed by the chemical cross-linking process endowed CFs-PEI-AO with excellent reusability and effective anti-biofouling activity. In the fixed-bed adsorption system, CFs-PEI-AO achieved a total uranium capture capacity of 1.042 mg g−1 after continuously flowing 30 L natural seawater for 15 days, and an impressive uranium removal ratio of 97.4 %, making it a promising candidate for uranium extraction from natural seawater. [Display omitted] • A novel eco-friendly fibrous adsorbent (CFs-PEI-AO) was facilely fabricated for uranium extraction from seawater. • The construction of molecular-level uranyl-specific nano-pocket endowed the adsorbent with ultra-high selectivity. • Schiff bases (C=N) endowed the adsorbent with superior anti-biofouling properties. • The adsorbent exhibited exceptional reusability with a desorption ratio of 84.93 % after 10 cycles. • This adsorbent is demonstrated as a high-performance and low-cost filler material for fixed-bed adsorption systems. [ABSTRACT FROM AUTHOR]

Extracting uranium from seawater, which contains hundreds of times more than terrestrial ores, furnishes a sustainable energy resource while curbing carbon emissions. Nanofibrous-based amidoxime is the most reliable uranium adsorbent due to its abundant chelating sites and large surface area. However, the amidoximation (AO) of polyacrylonitrile nanofiber (PAN NFs) produces brittle and shrunk AO-PAN NFs, and the spinning of pre-amidoximed PAN produces sub-micro stiff poly amidoxime (PAO) NFs, restricting their applicability. Herein, pre-cyclization (210 °C) and optimized amidoximation are applied to construct a hydrogel shell layer from PAO on cyclized electrospun PAN NFs. Among different amidoximation ratios, AO10-CPAN mats (10 g/L) with a thin hydrogel PAO shell layer exhibit excellent mechanical strength, high uranium adsorption capacity reached 380 mg/g at pH 8, and maintained their structure and 89 % of their initial adsorption capacity after six adsorption-desorption cycles. Furthermore, a 20.6 mg/g uranium adsorption capacity is reached after 15 days of circulating spiked (300 ppb uranium) natural seawater through the AO10-CPAN mats, proving their excellent selectivity and the open-chain amidoxime is the main compound of PAO shell. The surface amidoximed cyclized PAN (AO10-CPAN) mats satisfy the mechanical and physiochemical requirements for effectively extracting uranium from seawater. [Display omitted] • Optimize the construction of surface amidoximed cyclized PAN nanofibrous mats • Cyclized PAN NFs showed high flexibility and structure stability after the amidoximation. • Amidoximed cyclized PAN mats showed high mechanical strength and hydrophilicity. • AO10-CPAN mats exhibited a high uranium adsorption capacity (380 mg/g) and selectivity. • After 6 cycles, AO10-CPAN mats preserved their structure and adsorption efficiency. [ABSTRACT FROM AUTHOR]

In order to search for new desalination technologies to meet the growing water needs, this paper presents a parametric study of a novel, high-vacuum multiple-effect desalination system with barometric ejector-condensation activated with solar thermal energy, to demonstrate its technical feasibility. Aspen Plus simulation software was used for the parametric study, which was validated with the results reported in the literature. The high-vacuum multiple-effect distillation system has 14 effects, Top Brine Temperature of 68 °C and produces 96,033.6 L/d of water. The increase in the range of the pressure cascade (28.6–0.8 kPa), as well as of the temperature (68–4 °C), increases the capacity and efficiency of the desalination system. This is possible due to the implementation of an ejector that pumps, drags, and compresses vapor at 4 °C from the last effect of the system in order to condense it. In comparison to a conventional multiple-effect distillation, the Gain Output Ratio increases in 34.1 % because 25.4 % less energy from the generator is consumed. Furthermore, the system has a Recovery Ratio of 0.83, which corresponds approximately to a 120 % increase. Hence, the proposed desalination system significantly increases the potentiality of multiple-effect distillation systems. • A new MED system configuration that operates at high-vacuum; • A barometric ejector-condensation process is proposed to condense the vapor at 4 °C; • New operating conditions, which increase the efficiency of the system, are set; • The maximum sea-water pre-heating level is reached using less pre-heaters; • A variable-flow pump is used in order to ensure the proper functioning of ejector. [ABSTRACT FROM AUTHOR]

This study aims to assess feedwater, brine, and drinking water quality related to eight full-scale Egyptian seawater desalination plants. Collected water quality records from plants on the Mediterranean and Red Seas were monthly analyzed to identify different physical, chemical, and biological parameters during 2022. Statistical analysis and water quality indices (WQIs) approaches were applied to evaluate the various water quality states based on the available international and Egyptian guidelines. Analyzed seawater quality properties showed compliance with the most operating permissible limits except for high concentrations of turbidity, fats, oils, and greases, total bacteria in one plant, and iron, manganese, and silica in another plant. The monthly measured Weighted Arithmetic WQI classified 71 % and 100 % of desalination plants as having "Excellent" water rank according to the standard limits of the World Health Organization and the Egyptian Water Quality Standard, respectively. However, 65 % and 52 % of desalination plants were projected into the "good" water quality rank based on the Canadian Council of Ministers of the Environment WQI for the same guidelines. The results indicate that the feed intake type and the location of a desalination plant can optimize its performance efficiency, minimize contamination sources, and mitigate the potential environmental impacts of brine. • Eight full-scale desalination plants have been investigated considering two distinct feedwater sources and two intake types. • Potential environmental impacts of the brine from SWRO desalination plants have been explored. • The desalinated water quality has been assessed by developing two WQIs based on the drinking WHO and national standards. • RO membrane performance for large-scale desalination plants has been evaluated using one-year real data. • The suitable location for current or new desalination plants has been investigated and discussed [ABSTRACT FROM AUTHOR]

Solar-driven water evaporation has attracted widespread attention for its extensive applications in the production of clean water from seawater and wastewater. However, most of the designed evaporators focus on evaporation performance but ignore the antifouling ability, particularly the evaporator used for wastewater treatment. Herein, a cellulose acetate (CA)/polyaniline (PANI)/copper sulfide (CuS) nanofiber membrane with a core-shell structure was designed as an evaporator. The super-hydrophilic CA nanofiber membrane was obtained by deacetylation, which could provide sufficient water for water evaporation. Meanwhile, the in situ polymerization of PANI on CA nanofiber facilitates the growth of a uniform CuS layer on the fibers. Consequently, the synergistic effect between PANI and CuS not only improved the light absorption and photothermal conversion ability but also enhanced the photocatalytic ability of composite membranes. The d-CA/PANI/CuS evaporator exhibited a high evaporation rate of 1.45 kg m−2 h−1 under one solar radiation. Due to the excellent photocatalytic self-cleaning ability, the average evaporation rate of d-CA/PANI/CuS nanofiber membrane for methylene blue (MB) solution remained at 1.42 kg m−2 h−1 in a long-term evaporation experiment. This work may shine a new light on the design of novel antifouling evaporators with photocatalytic self-cleaning capability for seawater desalination and wastewater treatment. [Display omitted] • The d-CA/PANI/CuS membrane exhibited excellent light adsorption and satisfactory photothermal conversion capability. • The prepared d-CA/PANI/CuS membrane showed a high solar-driven water evaporation rate. • The d-CA/PANI/CuS membrane evaporator possessed a high efficiency for seawater desalination and wastewater treatment. • The synergistic effect of PANI and CuS resulted in an excellent photocatalytic ability of d-CA/PANI/CuS evaporator. [ABSTRACT FROM AUTHOR]

We report the pilot scale fabrication of thin film composite seawater reverse osmosis membrane (TFC-SW-RO) with low fouling propensity and improved permeate flux. In situ incorporation of poly(ethylene glycol) (PEG) into the polyamide (PA) network simultaneously improves the permeate flux (effect of hydrophilic channels) and antifouling property of the membrane. The PEG chains exhibit good stability during desalination of SW (NaCl = 33,000 mg L−1, applied pressure = 55.2 bar). The mechanism of PEG stabilization into the PA layer has been elucidated on the basis of hydrogen bond formation between ether linkage of PEG and carboxylic acid group of the PA network as well as steric hindrance posed by the network. The TFC-SW-RO membrane (no PEG) in several 100 m2 batches show pure water permeance of 1.4 L m−2 h−1 bar−1 and 98.5–98.8 % NaCl rejection during SW desalination. On the other hand, TFC-SW-RO-PEG shows pure water permeance of 2.2 L m−2 h−1 bar−1 with marginal drop in NaCl rejection (98.4–98.6 %). The TFC-SW-RO-PEG membrane exhibits improved antifouling (flux recovery ratio = 87 %) property during desalination of SW as compared to that of the pristine membrane (flux recovery ratio = 67 %). This work provides an important strategy for the fabrication of SW TFC RO membrane with improved performance. [Display omitted] • Pilot scale fabrication of SW TFC RO membrane was demonstrated. • PEG chains were incorporated during roll-to-roll membrane fabrication. • H-bond and steric restriction by the PA network stabilized the PEG chains. • PEGylation improved the membrane permeate flux and antifouling property. • NaCl rejection of about 98.5 % during seawater desalination. [ABSTRACT FROM AUTHOR]

Solar energy-driven interfacial evaporators are promising candidates to produce fresh water from seawater and wastewater. However, the photothermal layer of the evaporators under water and the homogeneous water transport layer cause undesired heat loss and inadequate water pumping, reducing the evaporation efficiency. Herein, we report on an advanced aerogel-based interfacial evaporator with self-floating photothermal layer and gradient structured water transport layer. The photothermal aerogels are prepared by assembling phenolic nanoparticles with increasing sizes from the bottom to the top, followed by surface hydrophobic modification and photothermal layer deposition on the large-pore side of the aerogels. The hydrophilic gradient phenolic matrix provides sustained water supply and facilitates water pumping by gradient capillary effect. Meanwhile, the large-pore and hydrophobic photothermal layer can enhance light absorption by multiple scattering and self-float above water for thermal localization. Thus, the obtained aerogels achieve high light absorption of 96.8 %, excellent evaporation rate of 1.64 kg m−2 h−1 under 1 sun irradiation and good long-term stability for at least 30 cycles without solute accumulation. Moreover, the produced distilled water from seawater and acidic/alkaline wastewater is in high quality and meets the World Health Organization's stipulated safe drinking water standards. [Display omitted] • Gradient phenolic aerogels with self-floating photothermal layer are prepared. • The aerogels possess high photothermal conversion and enhanced water pumping. • Highly efficient and stable water evaporation performances are achieved. • Fresh water can be produced from seawater and acidic/alkaline wastewater. [ABSTRACT FROM AUTHOR]

The powder structure, poor surface wettability and biofouling significantly limited the application potential of ZIFs (zeolitic imidazolate frameworks) in uranium extraction from seawater. Herein, a superhydrophilic polyethyleneimine assisted zeolitic imidazolate frameworks foam embed silver (CPEZ8A) was successfully prepared by simple chemical cross-linking and in-situ growth methods to explore the effects of hydrophilic matrix and silver antimicrobial agent on the uranium adsorption properties of ZIFs materials. The mechanical property and water contact angle test of CPEZ8A foam were performed to confirm its higher compression stress (with 1.314 MPa) and surface superhydrophilic. Moreover, CPEZ8A foam displayed an excellent resistance to biological attachment after 7 days in algae solution. Importantly, CPEZ8A showed the maximum U (VI) uptake capacity (775.19 mg/g) with 4.37 times of pure ZIF-8 at nearly seawater pH and retained relative high U-uptake amount during the broad pH range (4.0–9.0). Ion competition experiments were also investigated to verify the CPEZ8A foam excellent selectivity (K d = 15,072.1 mL/g). Notably, the removal rate of CPEZ8A foam reach 81.31 % in natural seawater and remain nearly 80 % in simulated contaminated seawater. Therefore, this work provides an effective strategy to develop highly efficient ZIFs adsorbents for uranium capture. [Display omitted] • A ZIFs composite foam was prepared for uranium uptake with anti-bioadhesion. • The co-effect of hydrophilicity and anti-fouling agent on uranium uptake of ZIFs was explored. • The foam demonstrates the high U-uptake amount during the broad pH range. • The maximum U(VI) uptake amount of foam is 4.37 times of ZIF-8 powder. • The foam exhibits the highly selective uranium adsorption in actual seawater. [ABSTRACT FROM AUTHOR]

Herein, novel sodium alginate/Cyphos IL101–loaded reduced graphene oxide/polyethyleneimine (SPGO; Cyphos IL101 = trihexyl (tetradecyl) phosphonium chloride) gel beads were prepared for highly selective extraction of uranium (U) resources from seawater. Results revealed that seawater pH (pH = 8) was the best adsorption condition for SPGO usage, and the adsorption rate of U reached >97 %. Further, in simulated seawater adsorption tests, the distribution coefficient of U was considerably higher than those of coexisting ions. In addition, U adsorption by SPGO, which was chemical adsorption, occurred via a spontaneous endothermic reaction. Mechanism studies revealed that carboxyl, hydroxyl, amino, and phosphate groups on the SPGO surface were involved in U adsorption. The addition of Cyphos IL101 significantly improved the selective adsorption performance of SPGO for U in seawater, and SPGO demonstrated excellent recycling capabilities. Thus, SPGO shows great potential for extracting U from seawater. • The optimum adsorption pH of SPGO for U after Cyphos IL101 loading was 8. • Loading of Cyphos IL101 improved the adsorption selectivity of SPGO for U. • The maximum distribution coefficient ratio of SPGO to U–vanadium was 15.6. [ABSTRACT FROM AUTHOR]

This study proposes a novel integration of seawater bittern and waste seashell recovery processes for CO 2 and SO x utilization. Furthermore, simultaneous optimization of waste seashells and Ca(OH) 2 separated from seawater bittern as an SO x absorbent was conducted to derive the blending ratio using a genetic algorithm (GA). The GA-based optimization process consists of four steps: (1) data generation using process model and data preprocessing, (2) DNN-based surrogate model development to predict the gypsum purity, CaCO 3 yield, and CO 2 emissions, (3) mathematical model development for TAC calculation, (4) GA-based optimization to derive the cost-optimal blending ratio and TAC. As a result, the derived cost-optimal blending ratios were scallop shells (0.03 %), cockle shells (0.03 %), clam shells (13.66 %), oyster shells (40.31 %), mussel shells (28.80 %), and Ca(OH) 2 (17.18 %), reducing the TAC by up to 10.88 % compared to conventional CO 2 and SO x capture processes. At the optimal blending ratio, the recycling efficiency of each seashell in the Republic of Korea was achieved from a minimum of 2.72 % to a maximum of 99.15 % annually. Therefore, this work makes a significant contribution to the chemical engineering field, providing an environmentally friendly, economical process and an efficient simultaneous optimization framework applied to the proposed model. • The research proposes a novel process integrating seawater bittern and waste seashells for CO 2 and SO x utilization. • A genetic algorithm is used to optimize the blending ratios of seashells and Ca(OH) 2. • The optimized process significantly reduces the total annualized cost by up to 10.88 %. • This approach provides a sustainable technique, utilizing waste resources effectively. [ABSTRACT FROM AUTHOR]

Uranium extraction from seawater is critical for the development of nuclear energy, but the progress is still seriously limited by the performance and cost of current adsorbents. Herein, a convenient and general co-condensation process is designed to prepare amidoximated multi-shelled hollow mesoporous organosilica adsorbent (AO-HMO), which exhibits a high uranium extraction capacity of 862.07 mg·g−1 in uranium-spiked simulated seawater and 9.67 mg·g−1 in natural seawater. The run-through mesoporous structure and multi-shelled surface provide fast diffusion channels and more active sites for uranium adsorption. Moreover, AO-HMO exhibits a long service life due to its robust structure, maintaining an ideal adsorption capacity over 10 adsorption-desorption cycles. Coupled with the synthesis-cost advantage, AO-HMO will surely show great application potential in uranium extraction form seawater in future. [Display omitted] • A novel organosilica-based adsorbent for uranium extraction is developed. • T-AO-HMO exhibits ultrahigh adsorption capacity both in simulated and natural seawater. • The run-through pore structure and multi-shelled active surface allows excellent selectivity for uranium. • Robust organic-inorganic hybrid framework enables outstanding reusability. [ABSTRACT FROM AUTHOR]

Batch RO technologies can help fulfil the growing need for high-recovery desalination. Several experimental studies have given results for batch and semi-batch RO processes individually, but under differing conditions. There is a lack of side-by-side comparisons. Here we report, for the first time, experiments with a high-pressure RO system that can be operated in batch, semi-batch, or hybrid semi-batch/batch mode. Using the same membrane and supply pump at pressures up to 110 bar, we compare performance against semi-batch mode which is used as the baseline throughout. With seawater feed, batch RO reduces electrical SEC by 10 % at recovery of 0.655. With brackish water feed, we use hybrid mode to avoid an excessively large work exchanger volume. Working at recovery of 0.94, a work exchanger volume of 20 L reduced SEC by 23 %. A work exchanger volume of 40 L reduced SEC further, resulting in SEC of 1.81, 1.89 and 2.02 kWh/m3 at recoveries of 0.9, 0.92 and 0.94 respectively, thus representing a 22–32 % reduction against the semi-batch baseline. The results also showed permeate conductivity reduced by up to 50 %. The study confirms the advantages of batch and hybrid RO over semi-batch RO, especially for brackish water desalination at high recovery. [Display omitted] • First direct experimental comparison among batch, semi-batch and hybrid RO • First experimental investigation of seawater desalination with 120 bar batch RO • Tests also included brackish water feed. • Effect of work exchanger volume investigated. • Hybrid mode achieved up to 32 % saving in SEC over semi-batch mode. [ABSTRACT FROM AUTHOR]

Various hybrid desalination systems have been proposed during the last two decades to improve the produced water quality, energy efficiency, water production rate and sustainability among others, receiving therefore a rapid industrial implementation. Desalination processes are energy intensive and this energy is mostly provided by fossil fuels, especially for large scale commercial plants. No doubt, the use of renewable energy (RE) sources is a way forward to decrease the environmental and related health impact to produce and supply freshwater in remote regions with severe water shortage and an unfavourable or unfeasible connection to the public electrical grid. However, most installed renewable energy desalination plants have small capacities, yet facing several issues for long term operation. Therefore, this study restricts to the use of fossil fuel based energy source for desalination and provides a thorough analysis summarising the design, operation, and performance, techno-economic and associated challenges of hybrid seawater desalination systems based on several experimental/real plant and simulation studies reported since 2000. It includes mature membrane-based and thermal-based desalination technologies, namely Reverse Osmosis (RO), multistage flash (MSF), and multi-effect distillation (MED), and a number of emerging hybrid membrane-thermal water desalination technologies. Future opportunities in hybrid systems, including RO/MSF and RO/MED are also highlighted. • Challenges and opportunities membrane and thermal seawater desalination processes are highlighted. • Fossil fuel based energy sources will continue to dominate in coming decades. • Application of renewable energy based energy sources is getting the momentum. • Several hybrid processes have potential for future commercial applications. • Hybrid processes can mitigate fouling/scaling problems and can be more energy efficient. [ABSTRACT FROM AUTHOR]

A diafiltration-nanofiltration-reverse osmosis (DiaNF-RO) process is introduced to achieve solutes fractionation of divalent/monovalent ions, i.e., Mg/Na, to enable resource recovery in seawater desalination and brine management. The diafiltration process is applied at the NF stage (i.e., DiaNF) to enhance the Mg/Na fractionation performance of NF (i.e., SF1 Mg-Na), while the RO is incorporated to produce desalinated water as well as diluent required by the DiaNF. By initiating the ion fractionation at the pre-treatment rather than post-treatment (i.e., RO-NF), the DiaNF-RO mitigates challenges of high concentration in RO brine management, which includes limitation of maximum allowable operating pressure and high energy requirement. The semi-empirical model, with at least 77.4 % accuracy, is first applied to simulate the performance of DiaNF-RO at different operating conditions and configurations (i.e., multi-stage and recycling). The sensitivity analysis then suggests that dilution should only occur in the last NF stage and without any retentate recycling, while NF pressure and element number should be optimized. Using NF membrane with SF Mg-Na of 1.28 at 10 bar and feed seawater of 35 g/L TDS, the optimal 4-stage DiaNF-RO design achieves maximum SF1 Mg-Na of 12.19 at 5.72 kWh/m3, or a minimum energy consumption of 5.41 kWh/m3 at SF1 Mg-Na of 7.04. Schematic diagram of a DiaNF-RO process. [Display omitted] • DiaNF-RO initiates divalent-monovalent ion fractionation at pre-treatment stage. • DiaNF-RO amplifies separation factor of nanofiltration membrane by 12 times. • DiaNF-RO achieves 12.2 Mg-Na fractionation at a competitive 5.72 kWh/m3. • Practical simulations are validated to analyse the design in continuous mode. • Optimal operating conditions are identified for ion fractionation. [ABSTRACT FROM AUTHOR]

The securing of lithium (Li) from resources containing low concentrations of Li+, such as brines and seawater, is receiving a lot of attention due to the rapid increase in demand for lithium-ion batteries. In this respect, the adsorption process is regarded as the most appropriate method for the direct extraction of Li+ from low-concentration solutions. However, for practical application, the adsorbent materials need to be shaped into granules, spheres, or foams using binding materials, which can reduce the adsorption performance by blocking adsorption sites. To overcome this drawback, an alternative method is proposed herein whereby the adsorbent lithium manganese oxide (LMO) powder is loaded into a multi-stage column (MSC) system equipped with a fabric filter. The optimum conditions for the fabrication of the LMO powder are found to be an Li/Mn molar ratio of 0.8 with a heating temperature of 500 °C for 4 h, and its delithiated product giving a maximum adsorption capacity of 23.9 mg g−1 from Li-spiked seawater (2–60 ppm). By comparison, stirring the adsorbent powder in solution for the same adsorption time yielded 22.8 mg g−1. The MSC adsorption process fits well with the Langmuir isotherm and pseudo second-order kinetics. To confirm the feasibility of the proposed method, its performance is also evaluated in the extraction of Li+ from natural seawater, giving Li+ recoveries ranging from 4 to 4.9 mg g−1 during repeated adsorption/desorption runs. Thus, the proposed method provides a practical Li+ extraction approach that can recover Li+ with a good adsorption performance. [Display omitted] • Synthesis of spinel LMOs by controlling Li/Mn ratio (from 0.5 to 1.0) • High Li+ extraction (up to 100 %) and Low Mn dissolution using delithiated LMO 0.8 • Utilization of highly efficient multi-stage column (MSC) system for Li+ extraction • Li+ sorption capacity of 23.9 mg g−1 from Li-spiked seawater using delithiated LMO 0.8 • Li+ extraction of 4 to 4.9 mg g−1 natural sea water using delithiated LMO 0.8 [ABSTRACT FROM AUTHOR]

Utilizing solar energy for interfacial solar steam generation and wastewater remediation is regarded as one of the sustainable approaches for alleviating clean water shortage. However, it is still a great challenge to comprehend all the requirements of efficient evaporation, salt resistance and wastewater treatment as well as low cost in one evaporator, thus hindering its large-scale practical application. Herein, in this work, an environmentally friendly and low-cost hierarchical porous architecture (APC@TMF) was prepared by assembling potassium citrate activated poplar catkin derived porous carbon (APC) into the porous structure of thermalized melamine formaldehyde resin sponge (TMF) by a simple dipping method. The APC@TMF integrates the advantages of APC and TMF, thus leading to good light absorption, low thermal conductivity, high hydrophilicity and fast water transport. As expected, APC@TMF exhibits a high evaporation flux of 2.28 kg m−2 h−1 with energy conversion efficiency of 96.3 % in seawater, which outperforms TMF, PVA/TMF, PVA/APC and recently reported evaporators. Beyond that, it demonstrates good performance for seawater desalination and wastewater remediation as well as high cost-effectiveness. APC@TMF hierarchical porous architecture, assembled by filling poplar catkin (APC) derived carbon into the porous structure of thermalized melamine formaldehyde resin sponge (TMF), is successfully prepared by a simple dipping method, exhibits outstanding solar-driven interfacial seawater evaporation and wastewater purification performance. [Display omitted] • APC@TMF was prepared by assembling biomass-derived carbon into thermalized sponge. • APC@TMF shows good performance in seawater desalination and wastewater remediation. • The hierarchical porous structure of APC@TMF helps reduce the evaporation enthalpy. [ABSTRACT FROM AUTHOR]

Interfacial solar desalination (ISE) emerges as a promising strategy to tackle the worldwide freshwater shortage. However, developing cost-effective solar evaporators that demonstrate exceptional evaporation rates while maintaining high salt-resistance is a tremendous challenge. This study introduces a three-dimensional (3D) solar evaporator, referred to as PPy-WMS, which is developed by employing a straightforward solution reaction to decorate polypyrrole (PPy) onto a waste mop sponge (WMS). The 3D PPy-WMS solar evaporator can capture ambient energy. When the exposure height is 6 cm, the PPy-WMS achieves an exceptional evaporation rate of 3.66 kg m−2 h−1 under 1-solar intensity. The macropore structure in WMS promotes water transport and facilitates salt ions backflow, resulting in high salt-resistance. The evaporation rate maintains at 2.91 kg m−2 h−1 when desalinating simulated seawater (20 wt%). Outdoor desalination experiments exhibit that 1 m2 of PPy-WMS can extract about 15 kg of freshwater per day. This economical and straightforwardly designed solar evaporator exhibits outstanding salt-resistance, presenting a viable remedy to address global freshwater scarcity. [Display omitted] • PPy-WMS with an exposure height of 6 cm achieves an excellent evaporation rate of 3.66 kg m−2 h−1. • PPy-WMS with a macroporous structure can resist 20 wt% simulated seawater with an evaporation rate of about 2.91 kg m−2 h−1. • 1 m2 PPy-WMS-6 can extract about 15 kg of freshwater per day. • PPy-WMS is cost-effective, performance-stable and durable. [ABSTRACT FROM AUTHOR]

With the scarcity of freshwater resources, solar desalination of seawater is a promising strategy for freshwater production. Compared to 2D evaporators with limited evaporation area, 3D evaporators can increase the evaporation area. However, traditional 3D evaporators cannot fully utilize the internal space of the evaporator for evaporation. In this study, a 3D trapezoidal multi-interface evaporator (Evap1), which composed of superhydrophilic sponges and superhydrophobic sponges arranged by alternate permutation for making full use of the inside structure of the evaporator to expand the actual evaporation area and achieve effective thermal management, were developed. The selective water transport channels and heat transfer channels were constructed by alternate permutation of hydrophilic and hydrophobic sponges in Evap1, while the top trapezoidal structure prevented heat from accumulating on the top surface of Evap1, which can enhance the efficiency of photothermal conversion. The Evap1 exhibited excellent evaporation rate of 3.6 kg m−2 h−1 under 1 sun illumination, and the evaporation rate was almost unchanged in brine with 20 wt% concentration for 8 h working. In addition, the Evap1 can achieve efficiently purificaiton of waste water containing dye, and the potential practical application of Evap1 was further proved by repeated and outdoor evaporation experiments. • Multiple evaporation surfaces were constructed to enlarge evaporation area. • The 3D trapezoidal arrangement improved sunlight utilization. • The macro-structure design of the evaporator achieved good thermal management. • The evaporation showed excellent performance in high concentration seawater. • Providing a effective strategy for constructing 3D solar evaporation devices. [ABSTRACT FROM AUTHOR]

The diafiltration-nanofiltration-reverse osmosis (DiaNF-RO) is an innovative process that aims to achieve ion fractionation of divalent/monovalent ions, i.e., Mg/Na (SF1 Mg-Na), an important step towards resource recovery, while producing clean water in seawater desalination at a reasonable specific energy consumption (SEC). Firstly, the novelty of DiaNF-RO process is compared with the RO-DiaNF process where ion fractionation is performed at the pretreatment stage (i.e., seawater) in the former and post-treatment stage (i.e., SWRO brine) in the latter. DiaNF-RO outperforms RO-DiaNF in many aspects, including higher Mg recovery, higher SF1 Mg-Na , lower scaling risk, and more efficient cost utilization, which emphasizes the benefits of initiating ion fractionation at low salinity in brine management. Secondly, the process practicality is reiterated by showing how desirable performance is achievable at low number of stages with some modifications. One possible adjustment is to improve NF membrane performance in the priority order of higher water permeability, lower Na rejection, and higher Mg rejection, which enables the 2DiaNF-RO to achieve the desirable SF1 Mg-Na of 13.7 at 5.71 kWh/m3. Another possible adjustment is to integrate the 2nd RO stage for more product water recovery to achieve a competitive net SEC (4.01 kWh/m3). These results further solidify the industrial implementation possibility of the DiaNF-RO process. Comparison between DiaNF-RO and RO-DiaNF, and enhancement of the 2DiaNF-RO process with improved NF membrane performance or 2nd RO integration. [Display omitted] • Pre-treatment is more preferred than post-treatment for Mg/Na fractionation. • Pre-treatment has better cost utilization for ion fractionation. • Higher NF permeability triples the Mg/Na fractionation. • 2nd RO stage integration reduces energy by 30 % at lower water cost. • Desirable 2DiaNF-RO performance emphasizes process practicality. [ABSTRACT FROM AUTHOR]

Pressure retarded osmosis (PRO) harnesses salinity gradient energy through the mixing of freshwater and saltwater, addressing the demand for sustainable energy sources. PRO typically utilizes river water or secondary wastewater as the feed solution, paired with seawater reverse osmosis (SWRO) brine as the draw solution. However, the limited availability of low-saline water presents a significant obstacle to energy generation. Therefore, the feasibility of a high-pressure PRO process utilizing seawater as the feed solution and hypersaline water as the draw solution was assessed to generate sustainable blue energy. Seawater has the potential to achieve the maximum extractable Gibbs-free energy through high-pressure PRO by maximizing the feed/draw ratio. The performance of the high-pressure PRO was theoretically evaluated, resulting in a tenfold increase in specific energy production compared to conventional SWRO-PRO due to the higher feed/draw ratio. However, high hydraulic pressure increased the membrane structural parameter and further reduced water flux and power density due to significant internal concentration polarization. Nevertheless, the high-pressure PRO process can achieve a power density exceeding 84 W/m2 when the structural parameter remains below 100 μm. The implications of the high-pressure PRO were further discussed to advance the concept of a blue circular economy, enhance environmental resilience, and promote sustainability. [Display omitted] • Feasibility of high-pressure PRO was investigated using seawater/hypersaline water. • Higher feed/draw ratio boosted energy production in the PRO process. • Seawater was assessed as a feed for high-pressure PRO for blue energy generation. • High-pressure operation raised the structural parameter reducing power density. • High-pressure PRO achieved >80 W/m2 at structural parameter <100 μm. [ABSTRACT FROM AUTHOR]

Seawater desalination plants using reverse osmosis (RO) in high temperature and high-salinity conditions, such as in the Middle East, face challenges such as limited achievable recoveries and high energy costs. This study evaluated the economic feasibility under seawater and high-salinity conditions by introducing a forward osmosis/crystallization/reverse osmosis (FO/Cry/RO) hybrid process. The optimization results were then used to compare the specific water cost (SWC), specific energy consumption (SEC), recovery, and permeate quality of the hybrid process with two different draw solutes and a conventional seawater RO process. In addition, a sensitivity analysis was conducted to determine how individual process parameters and operating conditions affect the economic feasibility of the proposed process under seawater and high-salinity conditions. The FO/Cry/RO hybrid process achieved a higher recovery with a lower SWC and SEC as the feed concentration increased compared to the conventional RO process. Utilizing waste heat further increased the economic advantages of the proposed process. In addition, much higher permeate quality can be obtained depending on the type of draw solute. The results of this study revealed that the proposed hybrid system outperformed the conventional RO process in terms of both energy efficiency and cost-effectiveness for seawater desalination under high-temperature and high-salinity conditions. [Display omitted] • Developed cost estimation models for an FO/Cry/RO hybrid process. • The hybrid process was found to be cost-competitive under high salinity conditions. • The hybrid process achieves higher recovery compared to conventional RO processes. • The hybrid process stably produces high-quality water in high-salinity conditions. • Utilizing waste heat markedly reduces the specific water cost of the hybrid process. [ABSTRACT FROM AUTHOR]

Herein, we present a new three-step route to prepare a covalently doped polyaniline (PANI) -based photothermal fabric with high evaporation capacity. In which, polyacrylamide (PAM) was covalently grafted onto the cotton yarns coupling with poly(glycidyl methacrylate) via electron beam irradiation induced co-graft polymerization as primary graft layer, while PANI was subsequently grafted onto the primary graft layer in situ, which was pre-functionalized by 2-(4-aminophenyl)ethylamine, as secondary graft layer. It has been found that the PAM-doped PANI-based photothermal fabric achieved high evaporation rate 1.60 kg m−2 h−1 from pure water, 1.54 kg m−2 h−1 from 3.5 wt% NaCl solution, and 1.49 kg m−2 h−1 even in 10 wt% NaCl solution under 1 sun irradiation. Furthermore, the evaporation-induced salt crystallization did not appear on the surface of fabric, but preferentially occurred on the area of supporting platform off the fabric. This characteristic endowed the doped fabric with average recovery rate of freshwater at 1.54 kg m−2 h−1 and salt at 0.03 kg m−2 h−1 from simulated seawater. This work provides a novel strategy to the enhancement of conductive polymer based photothermal materials via covalently doping, which could popularize the application of solar-driven evaporation to resource recovery from saline waters. • PANI-based photothermal cotton fabric was covalently doped. • Doped PANI-based photothermal fabric with higher photoelectric response. • 1.60 kg m-2 h-1 of water evaporation rate obtained from PAM-doped fabric under 1 sun. • Doped fabric achieved 1.54 kg m-2 h-1 of freshwater and 0.03 kg m-2 h-1 of salt from simulated seawater. [ABSTRACT FROM AUTHOR]

Parallel operation is a significant and feasible method to compensate the insufficient capacity of single reciprocating-switcher energy recovery device (RS-ERD) in membrane desalination system. To grasp the operating characteristics in capacity expansion, three parallel schemes of RS-ERD, single-operation scheme, two-parallel scheme and three-parallel scheme, are investigated through the numerical simulation, experimental verification and theoretical parameterization. Results indicate that, the two-parallel scheme and three-parallel scheme achieve the flowrate continuity of low-pressure seawater and the flowrate fluctuation amplitudes in parallel RS-ERDs decrease by 50 % and 83 % respectively when compared with single-operation scheme. Parallel operation schemes also broaden the flowrate range with high efficiency for RS-ERD. To ensure the 95 % energy recovery efficiency, two-parallel and three-parallel schemes expand the maximum flowrates to 140 m3/h and 210 m3/h in contrast with the 70 m3/h of single-operation scheme. In addition, the two-parallel and three-parallel schemes of RS-ERD realize the much lower specific energy consumption (SEC) of 2.11 kWh/m3 and 2.09 kWh/m3 than the 2.23 kWh/m3 in single-operation scheme which contributes to the operating costs savings about 63,830 CNY and 75,778 CNY in one year. This research provides a new perspective in capacity expansion through the parallel operation of energy recovery devices. [Display omitted] • Three parallel schemes of RS-ERD are investigated in simulation and validation. • A parameterization method is introduced to evaluate the operating characteristics. • The flow continuity of LP fluids is achieved in the parallel operating schemes. • The parallel schemes broaden the flowrate range with high efficiency for RS-ERD. • The SEC and operating costs are quantified and evaluated for desalination system. [ABSTRACT FROM AUTHOR]

The RO process cannot be operated in a thermodynamically ideal state, and in general, additional pressure is required. In addition, multi-stage RO involves an increased number of design factors compared to single-stage RO, and the feed pressure and SEC of multi-stage RO have a complex correlation with the design conditions. In this study, a comprehensive assessment was conducted to evaluate the advantages of multi-stage RO over single-stage RO. Specifically, we found ranges where the multi-stage process loses its energy advantage over the single stage depending on the total recovery rate and suggested a break-even point in terms of energy, theoretically and practically. Furthermore, we investigated the impact of design factors such as stage recovery rate, number of elements per vessel, and total number of membranes applied to each stage on energy consumption, and we also presented the optimal conditions for the design factors with theoretical support. Finally, we compared all configurations of single and multi-stage RO processes under optimal conditions and suggested an energy-efficient process. These investigations could offer valuable design heuristics for optimal multi-stage RO setups and provide insights into the advantages of multi-stage RO processes over single-stage RO processes. [Display omitted] • A comprehensive assessment of the multi-stage RO process was conducted. • In terms of energy, the break-even point between the multi-stage and single-stage RO processes is quantified. • The effect of design factors on energy consumption has been investigated and the optimal conditions are presented. • Design heuristics of practical RO systems for seawater desalination are provided. [ABSTRACT FROM AUTHOR]

Seawater desalination based on air-water interfacial solar heating has attracted significant attention in recent years. However, the "high temperature, high salinity, sunlight irradiation and enrichment of photosensitive substances" environment formed at the evaporator surface unavoidably enhances the photochemical reaction, which in the next step may lead to the production of active species and by-products. In this work, H 2 O 2 , as an important reactive oxygen species and a transit substance for reactive oxygen species such as ·OH, 1O 2 , and ·O 2 −, was monitored during solar evaporation. The average H 2 O 2 concentration at the evaporator surface was 2.24 mg·L−1 with a maximum concentration of 5.0 mg·L−1, which is significantly higher than the average H 2 O 2 concentration in the ocean. The effects of the nitrate ions, halogen ions, iron ions, dissolved organic matter, and solar intensity on the generation of H 2 O 2 concentrations were explored. Finally, halogenated by-products were detected at the evaporator surface when phenol, a model pollutant, was present in the feedwater. This work fills the knowledge gap in understanding the generation of H 2 O 2 and the formation of halogenated by-products at the evaporator surface during solar evaporation. [Display omitted] • Photochemical reaction at the evaporator surface was enhanced. • H 2 O 2 with max concentration of 5.0 mg/L was generated at the evaporator surface. • H 2 O 2 concentration could be adjusted by tunning the solar evaporation conditions. • Halogenated by-products were detected at the evaporator surface. [ABSTRACT FROM AUTHOR]

The current study detailed the impact of the qualitative and quantitative addition of biopolymers, besides the influence of the drying method on the efficacy of the prepared photothermal membranes in seawater desalination using the direct solar steam generation (DSSG) strategy. Three natural polymers (NP) (i.e. , cellulose acetate (CA), gum Arabic (GA), and sodium alginate (SA)), one synthetic polymer (i.e. , polyvinyl alcohol; PVA) were used in membranes' preparation at different (NP/PVA) weight ratios, while graphene oxide (GO) and silica aerogel (SG) were added as a photothermal absorber and to enhance membrane floatability, respectively. The solar-driven evaporation experiments revealed that the evaporation rates (ER) were enhanced by increasing the NP/PVA ratio. Freeze-dried photothermal membranes demonstrated higher performances (ER = 1.59–3.62 kg/m2/h) compared with the freezing-thawed membranes (ER = 1.36–2.95 kg/m2/h) under 1-sun illumination when the NP/PVA ratio increased from 1:1 to 2:1. Interestingly, among all freeze-dried membranes, SA-based membranes at (SA/PVA = 3:1) ratio reflected the highest performance (ER = 4.33 kg/m2/h) at 1-sun illumination. The recorded high ER can be interpreted by several features: increasing the hydrophilic character of the composite membranes at high NP/PVA ratios, the high microporous structure of the internal channels when applying the freeze-drying method; the high GO content which effectively converts light to thermal energy; adequate membrane thickness (∼0.5 mm); besides the presence of SG to maintain the membrane floatability inducing heat localization. Thus, the study provided low-cost freshwater production at affordable rates using biopolymers-doped graphene oxide for desalination using DSSG systems. [Display omitted] • Photothermal biopolymeric membranes for desalination by direct solar steam strategy • Freeze-drying method provided more efficient membranes than freezing-thawing. • Graphene oxide (i.e., photothermal absorber) enhanced the membranes' performance. • Low-cost freshwater production at affordable rates using green protocol [ABSTRACT FROM AUTHOR]

Processes for separating solutes from water, including desalination, are based on synthetic membranes using the forward osmosis (FO) technique. The industrial-level success of these membrane techniques has been astounding. Modern desalination membranes, however, cannot extract a single metal ion with precision from a commingled ion solution. Lithium, cobalt, uranium, and other energy-critical elements will soon be in greater demand than they can meet, thus elevating their importance as geopolitical resources. Critical metals can be found in seawater, an essential yet unconventional supply. Gold mining and ore processing are activities of great economic importance. However, they are related to generating extremely polluted effluents containing high concentrations of heavy metals and low pH. The review highlights the most recent design and deployment of FO desalination technologies, their application in sea mining, and the remaining challenges and prospects. This work also highlights the enormous potential of FO sea mining and how it is crucial to optimize the operating parameters, including draw solutions and energy consumption, and raise attention toward the economic aspect and market diffusion of FO sea mining. [Display omitted] • The advantages of using FO technology in sea mining are highlighted and discussed. • Several investigations, including FO energy consumption, and draw solute choice, are described in depth. • Draw solution characteristics, properties and choice criteria are highlighted and discussed. • Challenges and prospects using FO in sea mining have been proposed. [ABSTRACT FROM AUTHOR]

Water evaporation systems driven by solar energy delivers great potential for seawater desalination and sustainable energy generation, which is of great significance to relieve the worldwide shortage of fresh-water and energy. However, the achievement of well-designed materials and configuration for water evaporation systems remains a great challenge, hindering the realization of high evaporation rates and stable energy output. Herein, conductive coal-based nanocarbon material was creatively fabricated to assemble a novel multifunctional membrane based evaporation system for simultaneous solar thermal desalination of seawater and power generation. The coal-based multifunctional membrane (CBMM) possesses a permanently asymmetric wetting structure, which can ensure high photothermal evaporation efficiency and stable energy output. The constructed device unit demonstrate a long and stable operation in seawater under one sun irradiance for 100 h, achieving a high evaporation rate of 1.81 kg m−2 h−1 and a large voltage output of 410 mV. Especially, multiple units of the devices can be easily connected in series or parallel to power small electronic devices. This work provides a cost-effective and large scale method for the fabrication of coal-based nanomaterials and the creative application in high-perforamnce water evaporation systems for seawater desalination and sustainable energy generation. This study proposes a multifunctional membrane of conductive coal-based nanocarbon based on an asymmetric wetting structure for simultaneous solar thermal desalination of seawater and power generation. Devices assembled using this technology demonstrated a stable operation in seawater under one sun irradiance for 100 h, achieving an high evaporation rate of 1.81 kg m−2 h−1 and a large voltage output of 410 mV. [Display omitted] • Green and conductive coal-based nanocarbon was synthesized for a multifunctional membrane. • The multifunctional membrane possesses an asymmetric wetting structure. • The assembled evaporation system delivers desirable photothermal evaporation and energy output capability. [ABSTRACT FROM AUTHOR]

Previous studies on the utilization of seawater and brine have focused on either recovering Mg from seawater/brine using alkalis or extracting Ca from industrial byproducts using solvents. Therefore, the present study was aimed at recovering Mg and Ca simultaneously from simulated seawater/brine and slaked lime [Ca(OH) 2 ] using a simple process, with seawater/brine employed both as a Mg source and as a solvent for extracting Ca from the Ca source. Manipulating the concentration of the sucrose additive and the ionic strength of seawater/brine enabled Mg and Ca recovery with high efficiency and purity. The highest Mg recovery from brine was 75 %, and ~ 100 % pure MgSO 4 was produced; specifically, ~28 kg of MgSO 4 •7H 2 O was produced from 1 ton of brine. The impacts of sucrose concentration and seawater ionic strength on the Ca elution, carbonation efficiency, and size and shape of the resulting vaterite particles were analyzed. The purity of the vaterite produced was 94 %–100 %, and the maximum CaCO 3 yield per ton of the Ca(OH) 2 was estimated as 770 kg, with a carbonation efficiency of up to 92 %. Therefore, our cost-effective method—featuring the use of seawater/brine and Ca(OH) 2 —can concurrently produce economically demanding minerals such as MgSO 4 and vaterite, thereby facilitating resource conservation. • MgSO 4 and CaCO 3 are produced simultaneously from seawater and Ca(OH) 2. • The sucrose content and seawater ionic strength affect the mineral yield and form. • The Mg recovery efficiency is 75 %, and the MgSO 4 •7H 2 O yield is 28 kg/ton of brine. • The carbonation efficiency is 92 %, and the CaCO 3 yield is 770 kg/ton of Ca(OH) 2. • The MgSO 4 and vaterite powders obtained through the devised process are ~100 % pure. [ABSTRACT FROM AUTHOR]

A multi-stage nanofiltration (NF) system was developed with an inter-stage dilution feature for efficient magnesium (Mg) harvest from seawater or brine. The CaMg/NaCl and Mg/Cl ratios at each stage were used to design and evaluate its performance, while keeping the CaSO 4 scale deposition risk within the controllable range using anti-scalant. The pilot experiment was conducted using commercial-size 8-inch NF membranes, demonstrating its performance of divalent ions concentration while lowering the concentration of monovalent ions. This new NF system (NF-Mg) was then firstly introduced on a commercial scale in the Shoaiba Ph.4 SWRO desalination plant in Saudi Arabia, to supplement ≥15 mg/L Mg in the Shoiaba Ph.4 product water of 400,000 m3/d. During the NF-Mg commissioning period, the CaMg/NaCl, Mg/Cl, and stage-wise ion rejections by the NF membrane were evaluated, and operating conditions were identified to meet the desired Mg supplementation level. Finally, the Shoaiba NF-Mg system could demonstrate successful performance through its long-term operational data from Jun. to Dec. 2022. A techno-economic study shows the cost-effective supplement of Mg (13.2–23.4 (average 18.3) mg/L) in drinking water at the cost of 0.009–0.019 USD/m3. • A multistage NF system with an interstage dilution (NF-Mg) is proposed to utilize magnesium ion from seawater. • A 4-stage design could help to achieve the target ≥150% ratio of CaMg/NaCl and Mg/Cl indices. • A commercial-scale Shoaiba NF-Mg system has been producing concentrated and purified Mg brine since May 2022. • The cost of adding 13.2-23.4 mg/L of Mg to the product water of the 400,000 m3/d was evaluated as 0.009-0.019 USD/m3. [ABSTRACT FROM AUTHOR]

Hydrothermal liquefaction (HTL) employs subcritical water as a reaction medium for the conversion of biomass into biocrude, however, most research relies on freshwater as the reaction medium, posing a critical resource challenge. Although preliminary investigations have demonstrated the viability of seawater as an alternative medium for HTL, the mechanistic role of sea salt in HTL of biomass remains poorly understood. In the present study, individual biomass components—carbohydrate, lignin, protein, and lipid—were subjected to HTL under varying sea salt concentrations and temperatures. Sea salt exerted an inhibitory effect on biocrude yield during carbohydrate HTL process, but no inhibitory effect was observed in HTL of lignin, protein, and lipid. As for the impact of sea salt relative to that of sodium chloride (NaCl), it was found that at a moderate sea salt concentration (13.5 wt% relative to feedstock mass) and temperature (270 °C), the minor constituents in sea salt were favorable for HTL of protein and lipid in terms of biocrude yield, energy recovery, and carbon recovery. Our findings offer valuable insights into the benefits and challenges of employing seawater as a reaction medium and illuminate the complex roles that sea salt and its minor constituents play in HTL processes. [Display omitted] • Seawater viable for biomass-to-biocrude HTL, aiding freshwater conservation. • Sea salt impacts HTL yields differently across biomass model components. • Minor sea salt constituents influence HTL yields under specific conditions. • Seawater-based HTL holds promise for sustainable biofuel production. [ABSTRACT FROM AUTHOR]

The optimization of a membrane seawater desalination system is used to be a very complicated and time consuming process because tedious calculations are required to determine permeate recovery of the membrane system. This process can be greatly streamlined when the ideal reverse osmosis model is used to calculate the recovery of the membrane system. With this model, the pressure for a designated recovery can be determined conveniently and accurately from the basic parameters of a membrane system. Then the specific cost under various conditions can be calculated for the recovery. Finally, the recovery that minimized the specific cost for the permeate production can be easily determined graphically. The impacts of energy, membrane, feed water pretreatment, and concentrate handling on the optimal recovery of a membrane desalination process are demonstrated. The avoidance of a large number of equations and numerical integration in the determination of permeate recovery can greatly facilitate the optimization of design and operation of seawater desalination processes. • An efficient optimization method to minimize the cast of seawater desalination • Optimization of membrane system with the use of ideal RO model • The driving pressure for a given recovery determined graphically • Demonstrated of the method with three cases at different levels [ABSTRACT FROM AUTHOR]

Energy shortage severely impedes the advancement of human society and economy. The vigorous development of nuclear energy is a viable solution to address this issue. The escalating depletion of uranium resources necessitates prioritizing the selective extraction of uranyl from seawater and wastewater to ensure the prosperity of nuclear power. A bismuth-based MOF, CAU-17, was synthesized by the one-step solvothermal method for targeted selection of uranyl in the first time. The uranium adsorption tests demonstrated that CAU-17 exhibited a high adsorption capacity of 421.9 mg g−1 (T = 25 °C, pH = 7), exceptional selectivity, outstanding salt tolerance, and favorable stability with 83.6 % of the initial capacity retained after 5 cycles. Through the utilization of XPS and theoretical calculations, it was elucidated that the carboxyl oxygen that connects the Bi played a pivotal role in the binding process between CAU-17 and uranium ions, with bismuth acting as an electron regulator through its bridging effect with carboxyl oxygen. This work not only presents an exceptional uranium adsorption material but also elucidates the role of core metal atoms in MOFs during the binding to uranium process, thereby offering a novel perspective for future advancements in MOFs-based adsorbents. [Display omitted] • A bismuth-based MOF, CAU-17, was synthesized by the one-step solvothermal method for targeted selection of uranyl. • CAU-17 exhibited a high adsorption capacity (421.9 mg g-1), outstanding salt tolerance, and favorable stability with 83.6% of the initial capacity retained after 5 cycles • CAU-17 formed a complex coordination with uranium through carboxyl oxygen atoms while bismuth played a role in charge regulation. [ABSTRACT FROM AUTHOR]

Inadequate access to clean water and wasteful resource consumption during production pose significant challenges in global development. To combat these issues, interfacial solar steam generation (ISSG) has emerged as an energy-efficient solution to mitigate the ongoing water scarcity crisis. However, the application of ISSG is hindered by high costs and intricate fabrication processes associated with synthetic functional materials. In response, this study introduces an innovative approach that repurposes abundant by-products generated from hemp fiber production. Hemp fiber noil are transformed into a nonwoven fabric substrate, onto which hemp stem-derived biochar is seamlessly integrated using a straightforward spray-coating technique, establishing an efficient solar-to-heat conversion evaporator. Leveraging the durability of hemp fibers, this system achieves an impressive seawater evaporation rate of 1.47 kg m−2 h−1 under 1 sun condition, making it highly competitive in seawater desalination research. This pioneering strategy combines waste green materials and their functional counterparts, unlocking practical applications, addressing resource scarcity, and mitigating environmental pollution. This research highlights the potential of sustainable material utilization to tackle pressing global challenges. [Display omitted] • Repurposing hemp fiber by-products for the creation of a nonwoven evaporator • Employing hemp stem-derived biochar as efficient solar-heat conversion material • Seawater evaporation rate reached 1.47 kg m−2 h−1 with hemp evaporation system. • Absence of noticeable salt sediment on the surface of evaporator • Utilizing scalable needle-punching and straightforward airbrush processing [ABSTRACT FROM AUTHOR]

Due to the impact of freshwater shortage on coastal areas, coastal factories have gradually chosen seawater circulation cooling towers for industrial cooling. The circulating seawater easily generates thick scales, obstructs pipes, and affects heat transfer. Different from the development of scale inhibitors and membrane treatment, there are few fundamental researches on scale formation in seawater pretreatment. In this study, the effects of seawater concentration on scaling time and crystal shapes were investigated through on-line monitoring scaling experiments and scale collection. When the concentration of seawater increased (0.5–2.5 times), the scaling time was delayed, and the formation of large aggregates decreased. Subsequently, the scale delay of calcium carbonate caused by high ion concentration was confirmed by sodium and potassium ion gradient tests and the Visual MINTEQ model. The dynamic simulation further revealed that high ion saturation inhibits calcium and carbonate ions' collision, binding, and agglomeration. Sodium ions inhibit scale formation through electrostatic repulsion with calcium ions, while potassium ions occupy spatial sites around calcium ions. Furthermore, the aragonite formation tendency in highly ion-saturated solutions provides a theoretical basis for industrial carbon capture technology at the end of cyclic cooling. [Display omitted] • High concentration ratio of seawater inhibits scale formation. • Concentration of sodium or potassium solution affects the scaling time and the crystal form. • Collision, combination, and agglomeration process of scale-prone ions are hindered by other ions. • Seawater with a high circulation ratio is favorable for the formation of aragonite. [ABSTRACT FROM AUTHOR]

Climate change has prompted an increasing focus on responsible resource recovery, environmental sustainability, and the need for resilient infrastructure. Using a comprehensive review of literature and case studies, this article examines the design, impact, and resilience of coastal and offshore infrastructure for sustainable seawater mining. The findings reveal that: the integration of innovative engineering solutions improves operational efficiency and sustainability in coastal and offshore infrastructure for seawater mining; effective mitigation strategies lead to enhanced ecosystem health and water quality; resilient infrastructure incorporating adaptive design, nature-based solutions, and multi-hazard risk assessments increases the capacity to withstand climate change and sea-level rise impacts; incorporating sustainable practices positively contributes to overall sustainability and environmental performance. This research provides insights into the design, impact, and resilience of coastal and offshore infrastructure for sustainable seawater mining. It extends existing knowledge by presenting case studies and identifying managerial and policy implications. The originality of this research lies in its holistic approach, considering engineering solutions, environmental considerations, and resilience strategies, while emphasizing the importance of sustainability in seawater mining infrastructure. [ABSTRACT FROM AUTHOR]

Increased water extraction led to accelerated shrinkage of the Dead Sea, seriously damaging the environment and posing an economic risk for industry and tourism. The surrounding countries are willing to avert this looming crisis; however, previous approaches became infeasible due to economic, political and ecological hurdles. Motivated by this issue, we propose an alternative sustainable concept based on nanofiltration. We carried out basic design and cost estimations, showing that nanofiltration permeate produced from seawater allows environmentally friendly Dead Sea recharge, minimising gypsum precipitation, algae blooms and groundwater contamination potential on the conveyance routes. Dead Sea level stabilisation with nanofiltration permeate from Med Sea water costs between 0.54 and 0.7 $/m3 at 7 % weighted average cost of capital, significantly lower than treating Red Sea water (0.76 to 0.86 $/m3). Furthermore, providing NF permeate at the Dead Sea in transboundary exchange with Israel allows Jordanian and Palestinian inland desalination for regional potable water production. In the Jordan case, potable water costs at the major demand center, Amman, range between 1.56 and 1.76 $/m3, significantly lower than the national supply from the Red Sea. This study promises a new, feasible solution for trilateral research and implementation cooperation on the Dead Sea issue. [Display omitted] • A new concept of softening seawater for Dead Sea recharge has been evaluated. • NF permeate transfer from Med to Dead Sea has economic and environmental benefits. • Combination with inland desalination efficiently provides a new potable water source. • Renewable energy potential arises from differences in elevation and salinities. [ABSTRACT FROM AUTHOR]

Salt accumulation severely impacts the performance of solar desalination systems and hinders their long-term application in practice. Herein, we report a tilted 3D evaporator with high-performance salt-rejecting feature based on carbon nanodots (CDs)/luffa composite. The tilted 3D evaporator was designed by immersing one edge of CDs/luffa composite in a seawater tank and tilting at an angle to the horizontal plane. Upon solar irradiation, seawater was transferred through CDs/luffa composite at the bottom surface and wicked to the top surface for evaporation. Meanwhile, salt at the top surface was rejected back to the bottom surface and further taken away from the evaporator by the flowing seawater, thus avoiding salt accumulation for long-term solar desalination. Furthermore, the evaporator demonstrated effective thermal localization and absorption of environmental energy, possessing high evaporation rates of 2.05 and 1.50 kg m−2 h−1 when evaporation with water and real seawater, respectively (under one sun irradiation). Our study provides a promising strategy for salt rejection and enhancing the performance of solar desalination in practice. [Display omitted] • High-performance salt-rejecting feature based on carbon nanodots/luffa composite • Maintaining effective thermal localization and environmental energy absorption • High evaporation rate of 2.05 kg m−2 h−1 under one sun irradiation [ABSTRACT FROM AUTHOR]

A novel photoreceiver composed of black titania (BT) matrix with biochar for efficient steam production was investigated to measure the desalination efficiency under the illumination of one sun (1 kW m−2). The density of localized hotspots on the surface of the photothermal system is enhanced by the incorporation of AgCu core-shell that promotes photothermal activity and improves the degradation of methyl orange (MO) dye. Assemblages of AgCu nanoparticles on the surface of BT generated a strong stochastic plasmonic coupling and therefore broad-band absorption for much better solar energy consumption. The nanocomposite exhibited an excellent vaporization flux of 1.4 kg m−2 h−1 with high efficiency reaching 95.7 % under the illumination of one sun. AgCu@BT/BC exhibited an excellent surface temperature of 41 °C after only 5 min compared to other prepared photothermal systems. Furthermore, the prepared composites revealed superb degradation of MO dye under UV–vis light with a percentage of 96 %. The band gap energy of white titania decreased from 3.2 eV to 1.86 eV in the case of AgCu@BT/BC nanocomposite. Moreover, the crystalline AgCu@BT/BC demonstrates outstanding photocatalytic performance because of boosted charge migration, reduced electron-hole pair recombination rate, and identifiable shift to the red region. [Display omitted] • Green synthesis of eco-friendly biochar based on corn cobs waste • Facile transformation of white titania to black by molten salt method • Investigate the performance of black materials for solar steam generation under the illumination of one sun • Rejection of salts due to the presence of PVDF in the fabricated photothermal device • Study the photocatalytic activities of the prepared composites for degradation of MO dye [ABSTRACT FROM AUTHOR]

The solubility feature of redox electrolyte is a key factor to influence the performance of salt removal in redox flow electrode capacitive deionization. Herein, a novel redox flow desalination using ionic liquid (IL) as the eco-friendly solvent is proposed, i.e., 1-ethyl-3-methylimidazolium acetate. The high salt removal rate of 4.82 μg·min−1·cm−2 was obtained at the current density of 11 mA·cm−2. The low energy consumption of 254.12 kJ·mol−1 was achievable in IL, compared with 466.3 kJ·mol−1 in aqueous solution and 317.86 kJ·mol−1 ethanol. In addition, a long-term test with 11 cycles was conducted, and the real seawater was desalinated to a freshwater standard in batch mode. This work is significant for development of low-energy consumption in redox flow desalination via the usage of novel ionic liquids as solvent. An ionic liquid redox flow desalination device is proposed with the excellent solubility of redox couples, low energy consumption, high removal rate, long-term stability, and environment friendliness. [Display omitted] • A novel redox desalination system using ionic liquid (IL) as the eco-friendly solvent is proposed. • The energy consumption in IL-based FCDI system is significantly reduced. • Ionic liquid showed environmental friendliness and excellent stability as FCDI solvent. • Seawater is desalinated to freshwater. [ABSTRACT FROM AUTHOR]

A novel double-layered hydrogel based on the polyacrylamide matrix, pen ink, and phase-change microcapsules was developed to construct a hydrogel-based evaporator for efficient and continuous seawater desalination. The n -eicosane (core)@crystalline TiO 2 (shell) phase-change microcapsules were fabricated through interfacial polycondensation, and the resulting phase-change microcapsules obtained a considerably high latent-heat capacity of 187 J·g−1. The upper layer of the hydrogel exhibits a high solar absorptivity of over 90 % due to the introduction of pen ink as a solar absorber, which helps the hydrogel-based evaporator to gain an excellent photothermal energy conversion capability. A high evaporation efficiency of 93.89 % was obtained for the developed hydrogel-based evaporator along with a high evaporation rate of 1.85 kg·m−2·h−1 under one-sun illumination. The phase-change microcapsules dispersed in the lower layer of the hydrogel can act as a latent heat-storage unit to store a great quantity of photothermal energy through melting phase change by the phase change material core. This imparts a consecutive evaporation capability to the developed hydrogel-based evaporator. As a result, its water production was increased by 11 % under 50-min one-sun illumination and 50-min non-illumination. [Display omitted] • We developed a new double-layered hydrogel based on polyacrylamide, phase-change microcapsules, and pen ink. • The hydrogel was used to fabricate a solar-driven evaporator for continuous and efficient desalination. • Pen ink and phase-change microcapsules enhance the solar energy utilization efficiency of the evaporator. • The hydrogel-based evaporator exhibits an improved yield in clean water under intermittent solar illumination. [ABSTRACT FROM AUTHOR]

The world's water resources predominantly comprise salt water. In the face of forecasts of increasing demand for hydrogen obtained by electrolysis, it is becoming important to investigate the feasibility of seawater desalination. As part of a research project, the possibility of using a hybrid zero liquid discharge (ZLD) desalination system to desalinate seawater from the Baltic Sea was examined. In addition to analysing the operating parameters of the system, a detailed physico-chemical examination of the process water was carried out at each stage of treatment. It was found that the reverse osmosis (RO) and multiple-effect desalination (MED) systems allow sufficient water parameters to be obtained to feed the ion exchange (IX) system, and after deionisation it is possible to achieve the water parameters required by proton exchange membrane (PEM), anion exchange membrane (AEM) and alkaline water (AWE) electrolysers. Furthermore, the possibilities of concentrating brine in the multiple-effect desalination system and extracting salt in solid form in the ZLD system were verified. [Display omitted] • Hybrid ZLD system for Baltic Sea water desalination is studied. • Three different desalination systems: RO, MED and IX are considered for this analysis. • Two samples of salt after spray drying were tested. • Physicochemical analysis of the water after each treatment stage was carried out. • Deionised water obtained has parameters suitable for feeding PEM, AEM and AWE type electrolysers. [ABSTRACT FROM AUTHOR]

When graphene oxide (GO) based membranes are used to filter high concentration salt ion solutions at atmosphere pressure, flow of water molecules is easily blocked by the narrow spaces of graphene oxide membrane (GM), thus causing severely reduced permeability. To solve this problem, in this study, multilayer and composite framework membranes with multiple scale porous channels of sub-nanometer to tens of nanometers was designed and synthesized to promote effective flow of water molecules. These nanocomposite membranes were fabricated by crosslinking, condensation and self-assembly of polyacrylic acid (PAA), nanosized silica (SiO 2) and GO onto nylon membrane substrates using a vacuum filtration method. Their permeance obtained using 35 g·L−1 NaCl solution at a pressure of 0.98 bar was 38.6 L ∙ m−2 ∙ h−1 ∙ bar−1, about 1400 times of that using GM only, and their average retention rate was 27 %. The mechanisms of effective salt removal using these nanocomposite membranes were identified. Firstly the nanoscale SiO 2 increased the permeated flux of water by increasing the spacings and defects of GO sheets. The barrier structures and nanochannels formed by adding nanoscale SiO 2 effectively block the salt ions. Finally electrostatic adsorption of GO sheets and PAA provided more ion adsorption and rejection rates using the GO sheets. [Display omitted] • Polyacrylic acid (PAA) and nano-silica (SiO 2) were applied to prepare PAA@SiO 2 were applied to prepare. • PAA@SiO 2 -GM separated 35 g·L-1 salt solution with a permeability of 38.6 L∙m−2∙h−1∙bar−1 and ion removal rate of 27%. • Separation performance of PAA@SiO 2 -GM is attributes to fold barrier obstruction, gap defects and charge adsorption repulsion. [ABSTRACT FROM AUTHOR]