Seawater Desalination Applications Research Articles

Towel‐Inspired Fabric‐Based Evaporator for Highly Efficient Water‐Evaporation Desalination

AbstractSolar‐driven interfacial evaporation is an environmentally friendly and sustainable freshwater‐production technology with substantial market potential. Nonetheless, it encounters significant challenges related to energy‐conversion efficiency and resistance to salt crystallization. Thus, a towel‐inspired fabric‐based evaporator (TFE) containing various functional layers using carbon and cotton‐polyester‐blended fibers is designed and woven. The surface of the TFE is woven into a towel‐ring structure, which affords a high sunlight‐contact area and a superior sunlight absorption rate of 96.2%. In contrast, the hydrophilic layer at the bottom of the TFE delivers superior water‐molecule storage and conduction due to its multilayer corner‐interlocking fabric structure. Compared to commercial fabric‐based evaporators, the loop structure of the towel fabric enables water molecules to flow rapidly under the influence of wind, which effectively enhances the evaporation rate of the TFE. The optimal TFE can reach a high water‐evaporation rate of 3.72 kg m−2 h−1 under 1 kW m−2 sunlight and a wind speed of 2 m s−1, which is ascribable to sunlight/wind synergy. No precipitated salt is detected on the TFE surface after continuously evaporating a 3.5 wt.% NaCl solution for 8 h. These exceptional attributes position the TFE as a highly suitable candidate for diverse seawater desalination applications.

A Study on the Current Application of Seawater Desalination to Secure Living Water in the Islands of Jeollanam-do

A Study on the Current Application of Seawater Desalination to Secure Living Water in the Islands of Jeollanam-do

Revolutionary solar evaporation system: Harnessing the power of bacterial cellulose/Ag NPs/polypyrrole with its promoted antibacterial applications

Extensive research is being conducted on a promising technology that utilizes solar energy and photothermal materials to address the global challenges of freshwater scarcity and energy shortage. Real-world applications of this technology require materials with specific properties such as mechanical flexibility and antimicrobial characteristics. Herein, a self-supporting membrane for interfacial photothermal water evaporation is developed, incorporating bacterial cellulose (BC) as a resilient and hydrophilic backbone material, along with Polypyrrole（PPy）loading and silver nanoparticles (Ag NPs) doping. The addition of Ag NPs not only enhances the antibacterial properties of the material, but also improves light absorption through plasma resonance, resulting in enhanced photothermal conversion efficiency. Experimental results demonstrate that the BC/Ag/PPy hybridized membrane exhibits an outstanding photothermal evaporation efficiency of 91%. Additionally, the membrane maintains a stable evaporation rate and favorable mechanical properties. With its exceptional performance, this BC/Ag/PPy membrane offers a practical solution for long-term seawater desalination applications.

Interfacial Water-Dictated Oil Adhesion Based on Ion Modulation.

Oil adhesion on ionic surfaces is ubiquitous in organisms and natural environments and is generally determined by surface chemical component and texture. However, when adhesion occurs, water molecules at the solid-liquid interface, acting as a bridge not only influenced by the structure and composition of the solid surface but also interacting with the neighboring oil molecules, play a crucial role but are always overlooked. Herein, we investigate the oil adhesion process on a carboxyl-terminated self-assembled monolayer surface (COOH-SAM) in ionic solutions and observe the interfacial water structure via surface-enhanced Raman scattering (SERS) in this system. It is found that the lower the tetracoordinated water content, the stronger the oil adhesion. Compared to monovalent ions, the strengthened binding of multivalent ions to the COOH-SAM surface makes the interfacial water more disordered, which eventually leads to a stronger oil adhesion. Notably, the amount of oil adhesion decreases with an increase in the thickness of the interfacial water region. The interfacial water-dictated oil adhesion has been demonstrated in capillary to simulate the water-driven oil recovery, providing a molecular-level explanation for enhanced oil recovery from low salinity water flooding and also indicating potential applications in intelligent microfluidic and seawater desalination.

Environmental-friendly biomass-based Janus ink/urushiol modified cotton fabric for efficient solar-driven interfacial evaporation

Much attention has been paid to the interfacial solar-thermal conversion method for water resource purification. According to the hydrophilicity of ink carbon particles and the amphiphilicity of urushiol molecules (the main compound of Chinese lacquer), a novel environmentally friendly biomass Janus ink/urushiol modified cotton fabric was successfully prepared and exhibited one hydrophilic side and one hydrophobic side through simple immersion and spraying treatments. The Janus fabric displayed excellent water transport behavior, mechanical stability, thermal conductivity, and photothermal conversion performance. Under one stimulated solar radiation, the temperature of the Janus fabric increased to 85 °C in 2 min. Additionally, a photothermal vapor device prepared using a polyethylene ring and the Janus fabric demonstrated a high conversion efficiency of 94.3% with an impressive evaporation rate of 1.64 kg m−2h−1, which was 3.35 times the rate of water evaporation in the absence of the modified fabric. The Janus fabric showed satisfactory resistance to ultraviolet radiation and pH values. After 8 cycles (every 10 h) of exposure to outdoor sunlight, the modified fabric showed a slightly decreased evaporation rate, which could be restored to the previous level by re-spraying ink on the modified fabric. In the concentrated salt solutions, the solar-driven evaporator displayed excellent salt rejection capacity. During the desalination of high-concentration saline water, the Janus fabric showed acceptable diurnal correspondence. After desalination, the water quality reached the required standards for drinking water. In particular, the B3+ content droppingto 0.33 mg L−1(below the thresholdof 0.5 mg L−1). The solar steam generator also showed remarkable purifying capabilities for wastewater containing heavy metals and organic dyes. The Janus ink/urushiol fabric, prepared in an easy way, has a wide range of applications in seawater desalination and sewage treatment, which can be applied for mitigation of freshwater crises and environmental remediation.

Nb2CTX/graphene aerogels for efficient solar-driven steam generation

The development of high-efficiency photothermal conversion materials for seawater desalination is crucial to mitigating the global freshwater shortage crisis. The present investigation is aimed to prepare three-dimensional cylinder Nb2CTX/graphene aerogels (Nb2CTX/GAs) by a combined hydrothermal and freeze-drying process as a photothermal conversion material for solar-driven steam generation. The broad adsorption spectrum, porous microstructure, and excellent hydrophilicity account for the superior photothermal conversion performance of Nb2CTX/GAs. A high evaporation rate of 1.423 kg·m2h−1 was achieved as well as an exceptional solar steam conversion efficiency of 89.6% under one sun irradiation. Furthermore, Nb2CTX/GAs exhibited excellent cyclic stability of photothermal conversion. This work attempts to reveal the great prospect of Nb2CTX/GAs in seawater desalination applications.

Effect of Polydopamine/Sodium Dodecyl Sulfate Modified Halloysite on the Microstructure and Permeability of a Polyamide Forward Osmosis Membrane.

Mine water cannot be directly consumed by trapped people when a mine collapses, so it is difficult for people to carry out emergency rescues to ensure their safety. Therefore, a water bag made of a forward osmosis (FO) membrane has been designed that can efficiently filter coal mine water to meet the urgent needs of emergency rescue. Before interfacial polymerization (IP), sodium-dodecyl-sulfate-modified halloysite (SDS-HNT) was added to an MPD aqueous solution to prepare an SDS-HNT polyamide active layer, and then the prepared membrane was placed into a polydopamine (PDA) solution formed by the self-polymerization of dopamine and a PDA/SDS-HNT composite film was prepared. The results showed that the original ridge-valley structure of the polyamide membrane was transformed to a rod-, circular-, and blade-like structure by the addition of SDS-HNTs. Subsequently, a dense PDA nanoparticle layer was formed on the modified membrane. The polyamide/polysulfone forward osmosis membrane modified by co-doping of PDA and SDS-HNTs displayed both the best water flux and rejection rate, confirming the synergistic effect of compound modification. Therefore, the high-performance permeability of the polyamide membrane modified by SDS-HNTs and PDA provides great convenience for the emergency filtration of coal mine water, and also has potential applications in wastewater treatment and seawater desalination.

3D wood-based evaporator for highly efficient solar steam generation

Abstract Interfacial solar-driven steam generation is one of the most promising techniques used to produce clean water. However, achieving rapid water evaporation using solar steam generation devices is challenging because of their two-dimensional (2D) planar structures and confined evaporation areas. The three-dimensional (3D) structural design of evaporation devices improves water evaporation rates, thereby enhancing solar-driven steam generation. This study developed a 3D wood-based evaporator through 3D structure shaping and the flexible treatment of wood that involved coating photothermal materials with tannic acid. Because of the ampliative evaporation area and outstanding absorption, the water evaporation rate of the prepared 3D wood-based evaporator was as high as 2.5 kg m−2 h−1, and the efficiency of energy transformation was up to 101 % under simulated 1-sun irradiation; the evaporation rate and efficiency of energy transformation were considerably higher than those of 2D planar wood evaporators. Furthermore, the effective seawater desalination performance and good durability of the 3D wood-based evaporator were demonstrated. This study provides different insights into the fabrication of high-efficiency wood-based solar steam generators with high prospects for application in seawater desalination.

PEI-GOs/PVA photothermal sponge with enhanced interfacial solar steam generation and seawater desalination

Solar water evaporation technology based on photothermal materials is regarded as one of green and critical technologies for addressing freshwater scarcity. However, practical application of photothermal materials is limited by their high preparation cost, low evaporation efficiency, and poor photothermal conversion. In this study, a facile sponge with excellent photothermal and mechanical properties has been fabricated by mechanical-mixing and chemical-crosslinking of polyethyleneimine modified graphene oxide nanosheets (PEI-GOs), formaldehyde, polyvinyl alcohol (PVA) and sulfuric acid catalyst. The as-prepared PEI-GOs/PVA sponge shows excellent light absorption (95.1 %) under standard sunlight intensity of 1.0 sun (1 kW m−2) and a wide wavelength range of 200–2500 nm. The achieved high evaporation rate (1.80 kg m−2 h−1) is 4.7 times those of pure water (0.38 kg m−2 h−1). Moreover, the simulated seawater desalination experiment shows that the sponge has a good long-term stability and an average photothermal conversion efficiency of 88.5 %. The water purified by the sponge exceeds the quality of urban daily water. Therefore, this study offers a new facile route for fabricating a kind of photothermal sponge with good light absorption capacity, and water evaporation properties, which has potential application in seawater desalination.

Robust and versatile polypyrrole supramolecular network packed photothermal aerogel for solar-powered desalination

Solar-powered desalination is an emerging and sustainable water purification technology, that extends accessible clean water to relieve global water scarcity. Although great achievements have been made to develop interfacial photothermal materials, it is still challenging to simultaneously achieve high-level evaporation rates (>3 kg·m−2·h−1, 1 sun) and high-efficient energy conversion (>95 %) under 1 sun illumination. Herein, a polypyrrole supramolecular network-packed photothermal aerogel is designed and developed as solar-thermal evaporator to boost highly efficient solar-powered desalination. The photothermal aerogel integrates the photothermal, hydrophilic, and nanostructured polypyrrole supramolecular network to intensify solar-thermal energy utilization and reduce evaporation enthalpy, and the heat-insulating polysiloxane aerogel to enable mass transfer and suppress heat loss. The combined merits of the polypyrrole supramolecular network-packed photothermal aerogel promise outstanding evaporation rate of 3.61 kg·m−2·h−1 and remarkable solar-to-vapor conversion efficiency of 97.1 % under 1 sun illumination. Furthermore, polypyrrole supramolecular network imparts reliable salt resistance, cyclic stability, and environment tolerability for potential applications in solar seawater desalination. The comprehensive performance has considerable advantages over state-of-the-art materials. The study provides a new paradigm for the design of solar-thermal composites to advanced solar-powered desalination and contributes to future sustainable environmental and energy applications.

Compressible polyaniline-coated sodium alginate-cattail fiber foam for efficient and salt-resistant solar steam generation

Solar steam generation has attracted widespread attention because of its ability to produce clean water through desalination and wastewater treatment without conventional energy consumption. In this work, a polyaniline (PANI)-coated sodium alginate (SA)/cattail fiber (CF) foam for photothermal evaporator is prepared via directional freezing and oxidative polymerization. The SA/CF foam displays desirable water pumping capability because of the lamellar sandwich structure interconnected by porous networks. More importantly, the directional porous network architecture ameliorates the mechanical and salt-resistant performances of the SA/CF foam. The as-prepared PANI@SA/CF foam shows inferior heat conductivity of 0.047 W m−1 K−1 and outstanding light absorption over 96% in solar window. A vapor evaporation rate of 2.04 kg m−2 h−1 under 1 sun illumination is achieved for the PANI@SA/CF evaporator. Furthermore, the PANI@SA/CF foam could be employed in solar-driven freshwater generation from seawater and wastewater with high ion and dye removal rates. The combination of water evaporation and cleaning capabilities of the PANI@SA/CF foam as photothermal materials provide a framework for the exploration of next-generation evaporators in seawater desalination and wastewater treatment applications.

Design and optimization of a unique pilot scale forward osmosis integrated membrane distillation system for seawater desalination

The integration of forward osmosis (FO) and membrane distillation (MD) technologies for seawater desalination applications is recently gaining more importance since the system can be easily integrated with renewable energy resources. In this study a pilot scale FO integrated air gap membrane distillation (FO-AGMD) system is designed, commissioned, and tested for the desalination of the Arabian Gulf seawater (AGS) using 70,000 ppm solution of NaCl as the draw solution (DS). During the FO-AGMD operation, the FO feed-in conductivity decreased from 66.45 mS/cm to 63.31 mS/cm while the FO feed-out conductivity decreased from 62.92 mS/cm to 60.17 mS/cm. The DI water dosing system connected to the feed loop of the FO module decreased the feed-in and feed-out conductivities to maintain a uniform Δπ across the FO membrane. As the MD flux increased, to maintain the FO-AGMD system equilibrium the FO flux was also increased by raising the DS concentration using the dosing tank containing the stock solution of NaCl. Under the optimized operating conditions, the average system water recovery stabilized at 33% at the operating temperature of the MD at 85 °C. The water flux was stable between 6.3 and 7.3 L/m2h for the FO and 3.75 and 4 L/m2h for the MD. The major power consumption by the FO-AGMD system is the heating and cooling powers for heating the feed to ∼85 ºC and cooling the permeate to ∼10 °C in the MD section which varied in the similar range of 10–12 kW/h.

Comparative analysis of associated cost of nuclear hydrogen production using IAEA hydrogen cost estimation program

The interest in non-electric applications of nuclear energy is rising ranging from hydrogen production, district heating, seawater desalination, and various industrial applications to provide long-term answers for a variety of energy issues that both present and future generations will confront. Hydrogen is a dynamic fuel that can be used across all industrial sectors to lower carbon intensity. This study, therefore, aims at estimating the cost of nuclear hydrogen production from some light water reactors using International Atomic Energy Agency (IAEA) Hydrogen Calculator (HydCalc) program and comparing the result with similar existing studies conducted by other scholars using the Hydrogen Economic Evaluation Program (HEEP) program. The study employs six existing Light Water Reactors (LWRs) comprised of Korea Advanced Power Reactor 1400 MW electricity (APR1400), Russian VVER-1200, Davis-Besse Nuclear Power Plant in Ohio, Prairie Island NPP in Minnesota, Nine Mile Point NPP in New York, and Arizona Public Service's Palo Verde NPP to evaluate the Levelized cost of nuclear hydrogen production. Estimation of hydrogen demand was performed without carbon dioxide (CO2) tax since nuclear power has zero CO2 emission. The Levelized costs obtained using IAEA HydCalc and HEEP Programme were compared as follows; APR1400 cost are 2.6$/kg and 3.18$/kg, VVER1200 cost are 3.8$/kg and 3.44$/kg; Exelon cost are 1.7$/kg and 4.85$/kg; Davis Besse cost are 3.9$/kg and 3.09$/kg; Parlo Verde cost are 3.5$/kg and 4.77$/kg; Xcel Energy cost are 3.63$/kg and 0.69$/kg. The cost of hydrogen production using HEEP for Xcel Energy's Prairie Island NPP is 0.69 $/kg. This is because the reactor utilizes High Temperature Steam Electrolysis, method of hydrogen production, while the other methods employs Low Temperature Electrolysis. The results shows that the final price of the hydrogen for each reactor technology depends not only on the production method but also on the cost of the nuclear power plant and the production rate of the hydrogen plant.

Covalent organic framework membrane with sub-nano pores for efficient desalination

Covalent organic frameworks (COFs) have emerged as advanced membrane materials for molecular separations, but it is rarely used for desalination due to the mismatch between the COFs pore size (1−5 nm) and the diameter of hydrated ions (<1 nm). Herein, we designed and fabricated an imide-linked TbTG COF membrane (COFM) with intrinsic sub-nano pores. The TbTG nanosheets were prepared by interfacial polymerization, and then self-assembled into COFMs on the porous PAN substrate. The sub-nano pore size (∼0.4 nm by simulation) conferred excellent size sieving capacity to the TbTG COFM with the molecular weight cut-off of only 180 Da, which was the lowest among COFMs ever reported. Moreover, the positive charge on the skeleton of TbTG COFM greatly fortified the Donnan effect. The TbTG COFM exhibits excellent salt rejections of 98.7% to Na2SO4, 99.1% to MgSO4, 99.5% to MgCl2 and 93.3% to NaCl, respectively. The TbTG COFM also maintained high salt rejections under both high salt concentration up to 10000 ppm and high pH value of 9.4, showing great potential in seawater desalination applications.

Novel Amino Acid Derivatives for Efficient Methane Solidification Storage via Clathrate Hydrates without Foam Formation

Although anionic surfactants are considered the most efficient kinetic gas hydrate promoters for gas storage applications, gas recovery and reuse of surfactants are difficult due to high foam formation during hydrate melting. Additionally, most anionic surfactants are toxic, which has an intense environmental effect. In this study, novel amino acid derivatives (ACDs) were developed as the first class of superior promoters compared to surfactants without foaming during the formation and recovery of gas hydrates. The results of high-pressure autoclave experiments indicated that all ACDs significantly enhanced the kinetics of methane hydrate formation at 500 ppm. ACD5 derived from leucine showed the best promotion effect in distilled water by providing a total mole consumption of 436.1 mmol. ACD5 increased the degree of water-to-hydrate conversion from 39.6% in pure water to 94.3%, which was higher than in sodium dodecyl sulfate (SDS) solution (87.8%). Moreover, differential scanning calorimetry experiments demonstrated that ACDs could form methane hydrates at relatively lower temperatures than pure water. They increased the onset temperature of methane hydrate formation from −15 °C in pure water to −12 °C at 500 ppm. A higher promotion activity than SDS was also observed for ACDs in salt water, suggesting that seawater can be used to produce methane hydrate instead of pure water to reduce gas storage costs. Besides, visual observations revealed that no foam was formed during melting hydrates and releasing methane in the presence of ACDs. These findings show that a slight modification of amino acids makes them efficient candidates for improving gas hydrate formation for seawater desalination and gas storage applications.

Vacuum-Dried and Intrinsic Photothermal Phenolic Carbon Aerogel from Coal Tar Rich in Polycyclic Aromatics for Efficient Solar Steam Generation

Solar steam generation has been proven to be an efficient way for obtaining clean water from seawater or polluted water with solar energy as the only energy input. Due to the high porosity and light absorption, tunable micro–nano structure, and excellent thermal insulation, carbon aerogels as photothermal materials have attracted much attention. However, requirements of freeze drying and additional light absorbers as well as low strength restrict the large-scale utilization of carbon aerogels. Herein, self-floating and low-cost coal tar-based phenolic carbon aerogels (CPCAs) were fabricated using a facile method, that is, polymerization/gelation, vacuum drying, and carbonization. CPCAs with comparable light absorption (96.6%) to carbon nanotube can be used as intrinsic photothermal materials owing to the existence of considerable polycyclic aromatics in coal tar. In addition, CPCAs possess hierarchical porous architectures and abundant polar functional groups, delivering fast water transportation. Moreover, the latent heat is obviously reduced due to the regulation of the water state. Therefore, the evaporation rate can reach up to 2.23 kg m–2 h–1 with an energy efficiency of 92.5% under 1 sun employing a CPCA as a photothermal material. Additionally, CPCAs with high strength (more than 4 MPa under 90% compressive strain) have versatile applications in seawater desalination and industrial wastewater for long-term stability. The excellent performance of CPCAs was tentatively revealed by density functional theory and COMSOL calculation.

A flexible, high-efficiency, and low-cost FeS2@CTS hydrogel film for solar interface water evaporation

Solar interfacial water evaporation to obtain pure water has attracted extensive attention in recent years. In this work, based on the excellent optical property of FeS2 and the cross-linking nanostructure of chitosan (CTS), a FeS2@CTS hydrogel composite film for solar interfacial water evaporation was developed by hydrothermal synthesis and the following composite coating technology. The prepared FeS2@CTS presented high solar absorptivity of 95.27% and fast optical response capability. Under the optimized condition, the evaporation rate of pure water reached 3.34 kg m−2 h−1 and the photothermal conversion efficiency was 103.06% under one sun irradiation. In five runs, the evaporation rate of the FeS2@CTS was stable, indicating the excellent cycle stability. Also, in the desalination test, the stable evaporation rate of 1.74 kg m−2 h−1 was obtained in five runs. Due to the simple preparation method, low cost, and outstanding interfacial evaporation property, this FeS2@CTS indicates great potential for the seawater desalination or other photothermal conversion applications.

Controllable synthesis of nickel–cobalt-doped Prussian blue analogs for capacitive desalination

The unique framework structure of Prussian blue imparts excellent sodium storage capacity and cycling stability, thus making it an ideal capacitive deionization (CDI) electrode. Herein, Prussian blue analogs were prepared by the controlled doping of nickel–cobalt bimetallic ions to improve their desalination capacity and stability. Process parameters such as cell potential, current, inlet flow rate, and solution concentration were investigated to determine the optimal conditions for Prussian blue desalination, and a high-performance Prussian blue analog (CNF-4) was successfully synthesized by accurately controlling the nickel–cobalt doping ratio. The desalination capacity and rate of CNF-4 (Ni:Co=1:2) reached 65.31 mg g−1 and 4.38 mg g−1 min−1, respectively, and 98% of the capacity retention rate was maintained after 50 cycles of desalination. The excellent capacity and performance of the CNF-4 material indicate its superiority to conventional PBA CDI electrodes and its prospective applications in seawater desalination.

Architecting the Water State of Polypyrrole/Polyvinyl Alochol‐Wood Evaporator to Enhance Water Yield in Multistage Solar Stiller

Solar desalination is one of the most promising ways to produce freshwater. Interfacial solar steam generation system is especially studied for its high solar–thermal conversion efficiency. However, the phase transition process of water evaporation is energy intensive and a salt cluster is easily accumulated at the surface of the evaporator, which limits the water yield and stability of the distiller. Herein, a hybrid design involving tuning the water state, recycling latent heat, and spatial localizing low‐concentration zone to distill for stable and efficient solar‐water harvesting is demonstrated. In a two‐stage distiller, the water yield can reach 1.62 kg m−2 h−1 under one sun irradiation, corresponding to the solar‐to‐vapor conversion efficiency of 110%. The scale‐up device can also steadily operate for 1 week outdoors. This work provides an effective strategy for high‐efficiency solar distillation, holding the promise of application in seawater desalination and domestic water supply.

3D carbonized grooved straw with efficient evaporation and salt resistance for solar steam generation

Solar steam generation (SSG) is considered an effective solution to the global shortage of freshwater resources. To solve the practical application challenges of SSG in remote outdoor environments where electricity is scarce, it is of great importance to developing new solar evaporators. In this study, a three-dimensional (3D) biochar solar evaporator based on carbonized grooved straw was prepared from agricultural waste corn straw, which had high solar energy conversion efficiency and excellent salt resistance. The existence of grooves increases the surface area to absorb more sunlight and makes the light multilevel reflection improve the evaporation rate. The excellent light absorption, super hydrophilic, and heat shielding properties of 3D carbonized grooved straw resulted in a good evaporation rate (1.57 kg⋅m−2·h−1) and energy efficiency (85.9%) under 1 sun irradiation. The 3D grooved biochar solar distiller also demonstrated efficient formation evaporation performance and excellent salt resistance in practical applications in seawater desalination and surface water purification. The 3D grooved biochar solar distiller prepared from agricultural waste has the advantages of being economical and environmentally friendly, with good application prospects.