Seawater Desalination Technology Research Articles

Synthesis of CuO/Fe3O4 Nanocomposite for enhanced solar thermal desalination

Nanoparticle (NPs) have attracted the attention of scientists and researchers in water remediation due to the improvement in its processability, and its cost effectiveness. The present work analyzed the synergistic effect of CuO (NPs) with different ratios (0, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 wt %) on the structural, and optical properties of Fe3O4 (NPs), that can be used in water desalination process. The general methodology for preparation and structural properties of CuO (NPs), Fe3O4 (NPs) and CuO/Fe3O4 (NCs) were analyzed by (XRD) and (TEM) measurements. The morphological combination of (SEM) with (EDX), were used for determining the elemental identification of CuO/Fe3O4 (NCs). The characterization topography was found to be strongly affected by the change of the CuO concentration. Furthermore, the Urbach energy (EU), steepness parameter (σ), electron-phonon interaction (Ee-p), optical band gap (Eg), refractive index (n) and optical conductivity (σopt) were calculated. The optical absorption studies in the UV–Visible region, revealed that the CuO/Fe3O4 (NCs) was found to be direct allowed transition, and the energy bandgap value decreased from 2.52 eV to 2.15 eV based on the percentage change of CuO (NPs) in CuO/Fe3O4 (NCs). Moreover, the value of thermal conductivity (k), and thermal efficiency (η), showed an increase with the increase of the ratio of CuO (NPs), which may be an indication for opening an innovation way that can satisfy the need of seawater desalination technology.

Energy and exergy analysis of a novel solar-powered passive multi-stage osmosis desalination system for sustainable water production

Climate change and population growth constantly exacerbate global water scarcity, and seawater desalination technology is crucial to addressing this crisis. Conventional fossil-fuel desalination poses environmental and economic challenges, especially in remote, water-scarce regions. Renewable energy offers sustainable options for seawater desalination; however, most related technologies face challenges in flexible deployment. Among passive technologies, interfacial evaporation still confronts issues of salt accumulation impacting desalination efficiency. Therefore, this study investigates a novel solar-powered passive multi-stage osmosis device that emulates mangroves’ transpiration and natural osmosis processes. Harnessing solar energy, it employs hydrophilic nanoporous membranes for water movement and evaporation and an osmosis membrane for solute retention, aiming for efficient seawater desalination without external power and pressure. Energy and exergy analyses reveal key efficiency factors. Results reveal significant pressure gradients across the osmosis membrane as a challenge. Optimizing salinity and adjusting the area ratio of the nanoporous membrane to the osmosis membrane is vital for stability and performance. Moreover, potential increases in water production from 0.97 kg/m2/h to 3.53 kg/m2/h with a five-stage setup, though benefits diminish with additional stages due to heat/exergy losses. The exergy efficiency increases from 0.14 % for a five-stage device to 0.18 % for a ten-stage system. This study demonstrates the solar-powered passive multi-stage osmosis device’s dependence on solar flux and highlights the importance of optimizing the air gap thickness and insulation to boost efficiency.

Floating graphite felt-cellulose multilayer sandwich evaporator for solar salt-resistant seawater desalination: Mechanistic role of incorporated super water holding layer

Solar-to-steam generation (SSG) for seawater desalination is emerging process which faces several technology challenges for successful scaling up. Floating solar-to-steam generation (SSG) sandwich-based systems using hydrophilic water bridges have been proved to be fascinating technology for seawater desalination. However, the mechanistic pathways of heat dissipation, mass diffusion and convection are still the key bottlenecks for reliable scaling up. To solve the heat loss and surface salt deactivation, we demonstrate herein the performance of novel SSG structure for seawater desalination via the incorporation of cellulosic sponge as water holder to play a role of water transit between hydrophilic bridge and the top surface. Two systems using low-cost materials were compared, namely graphite felt/hydrophilic paper/polystyrene (GF-HP-PS) and Graphite felt/Water receiver/hydrophilic paper/polystyrene (GF-HP-WR-PS). The process of heat generation and localization was maximum in the GF-WR-HP-PS system, reaching 68.2 °C under 0.5 sun. The photothermal conversion efficiency was found to be 92 and 114 % under 0.5 sun for GF-HP-PS and GF-HP-WR-PS, respectively. On top of that, GF-HP-WR-PS shows effective steadily salt rejection during the desalination of seawater. The WR layer plays a crucial role to govern the confined water, which boosts the dissolution of salt and its convection without significant heat downward convection. As a practical consideration, the cost of used components to fabricate this SSG system is very acceptable and without major restrictions.

Interface Structure Strengthening of a Mesoporous Silicon/Expanded Perlite Microevaporator for Efficient Solar-Driven Interfacial Evaporation.

Solar-driven interfacial evaporation is one of the cutting-edge technologies for seawater desalination and wastewater purification. Herein, a floating carbon-coated silica microsphere/expanded perlite integrated interfacial microevaporator (HEPCL) is reported. The carbon nanolayer allows the HEPCL to have better broadband light absorption performance than natural graphite and graphene oxide. Through the low density of expanded perlite, HEPCL particles can self-float on the water surface and self-aggregate into an integrated whole under surface tension, which enhances the heat collection capacity. The hierarchical porous structure of the HEPCL has a continuous water absorption capacity. Notably, water molecules adsorbed in the HEPCL have a high desorption energy, which reduces the water evaporation enthalpy (1621 kJ/kg), making it easy to remove with external energy. Thanks to the design merits, the HEPCL achieves a water evaporation rate of 1.551 kg m-2 h-1 (efficiency of 94.85%) under 1 sun irradiation and may inspire a practicable solution of water scarcity.

Salt Resistant PPy/MXene Flexible Waffle Type Fabric for Efficient Solar Evaporation and Water Purification Production.

In recent years, with the development of solar seawater desalination technology, many solar evaporators are affected by precipitated salts during the evaporation process, which can reduce efficiency. In this work, flexible fabrics made of polypyrrole (PPy)/MXene are obtained by impregnating the prepared PPy ink onto waffle like fabrics. The combination of PPy and fabric greatly improves the water absorption and evaporation performance of the fabric. The average evaporation rate of this structure is 1.43kg m-2 h-1, and the average evaporation efficiency under a single light source is 85.13%. After a 15-h testing cycle and a total of 8 cycles, lasting nearly 120 h, the performance of the device remained stable. The structural characteristics of waffle fabric, based on the Marangoni thermal effect, make it possible to suppress salt precipitation during evaporation, avoiding large salt particles covering the evaporation surface and reducing efficiency. This experiment successfully demonstrated long-term stable water evaporation, providing new ideas for the development of fabric evaporators.

Tree rings-inspired 3D solar evaporator fabricated by rolling polypyrrole decorated waste cotton fabric for efficient desalination

Interfacial solar steam generation (ISSG) has drawn considerable interest as an emerging technology for seawater desalination. However, designing simple and cost-effective solar evaporators with high salt resistance and impressive evaporation rates remains a significant challenge. Inspired by tree rings, a three-dimensional (3D) solar evaporator (PPy-RWCF) was fabricated by rolling polypyrrole-decorated waste cotton fabric (PPy-WCF) into a cylinder. The synergistic effect of polypyrrole (PPy) and interstices within the waste cotton fabric (WCF) allows the PPy-RWCF to absorb around 99.00 % of sunlight. The PPy-RWCF, with an exposure height of 3 cm, achieves an excellent evaporation rate of 2.36 kg m−2 h−1 under 1-solar intensity. Besides, the vertical water channels within PPy-RWCF allow rapid solution transport, enabling it to withstand 20 wt% brine with an evaporation rate of 2.05 kg m−2 h−1. Prolonged outdoor desalination testing has demonstrated that a 1 m2 PPy-RWCF can generate approximately 10 kg of freshwater daily. This study proposes a sustainable approach to the development of solar evaporators utilizing WCF for desalination of high-salinity water.

Multiscale MXene Engineering for Enhanced Capacitive Deionization via Adaptive Surface Charge Tailoring.

Capacitive deionization (CDI), renowned for its eco-friendly and low-energy approach to water treatment, encounters challenges in achieving optimal deionization efficiency and cycle stability despite recent advancements. In this study, the CDI electrodes were crafted with multilevel pore structures using modified cellulose (MCNF) and porous activated MXene (PAMX), aiming to the impact of surface modification on adsorption efficiency, stability, and overall performance. The experimental results demonstrated the superiority of the electrode, specifically the formulation integrating sulfonic acid-treated cellulose and PAMX (SCNF@PAMX). This configuration exhibited remarkably a higher desalination rate (3.91 mg·g-1·min-1) and enhanced desalination capacity (31.24 mg·g-1), with cycling performance exceeding 90%. Density functional theory calculations underscored the formidable adsorption energy of SCNF for Na+ (2.15 eV), surpassing that of other modified electrodes. The enhancement of deionization performance and efficiency through surface charge modification, altering Na+ electrostatic adsorption, lays a solid foundation for advancing more efficient and durable seawater desalination technologies.

Seawater desalination of arid regions: comparing the policy of the Kingdom of Saudi Arabia and Indonesia

Problems with clean water in coastal areas alongside an increase in population and community economic activities have diversified community activities. Coastal settlements bordering the high seas are characterized as arid areas with a lack of clean water. Here, the use of the range groundwater supply against seawater intrusion means that the water consumed by the community tastes salty and brackish. The availability of abundant seawater, processed through desalination technology, can be used to meet the daily clean water needs of coastal communities. Sustainable development goal (SDG) 6 Water and Sanitation is concerned with ensuring that everyone has access to clean water and sanitation. In this regard, desalination technology is considered viable to achieve the SDGs in the environmental sector. Some countries have focused on using desalination technology to achieve target 6.4 by 2030. This goal aims to improve the efficiency of water use to reduce the number of people experiencing clean water scarcity by ensuring a sustainable supply of fresh water. The objective of this study is to examine the application of seawater desalination technology for clean water in the Kingdom of Saudi Arabia (KSA) and Indonesia, and identify the implications of desalination policies in these countries. Comparative studies were conducted using secondary data and literature studies on transforming seawater into clean water with technology. KSA applies seawater desalination technology to meet water needs. However, in Indonesia, policymaking has not holistically examined the potential of using seawater desalination technology for clean water. Until now, unlike in the KSA, Indonesia has not addressed the importance of the use of desalination technology in state policy.

Optimal configuration of low‐grade waste heat driven seawater desalination using data envelopment analysis: A case study of industrial application

AbstractWater supply challenges are caused by population growth, industrialization, as well as the scarcity of freshwater resources. Low‐grade waste heat‐driven seawater desalination technologies may improve the water‐energy nexus issues of desalination systems by different configurations. The data envelopment analysis is used to determine the best final decision to achieve a better comparison of different parameters. The optimal configuration of low‐grade waste heat driven seawater desalination is studied using flue gas waste heat in heat recovery boilers of an industrial oil refinery. Nine different types of multistage flash and multi‐effect distillation (MED) desalination plants have been considered. The results show that the multistage flash brine recirculation may produce more desalinated water while the multi‐effect distillation with three stages (3‐stage MED) has the best payback period. Using 3‐stage MED with a production of approximately 19,630 kg/h of water from 5.3 MW exhaust gas is more suitable for this design. Thus, the proposed strategy guides us toward the best decisions to configure low‐grade waste heat‐driven desalination plants for better design considering rigorous simulations for the plants. Moreover, this framework enables us to consider different criteria of technical, economic, and environmental issues for optimal configuration.

Carbonized sawdust based solar absorber in a solar still for seawater desalination

AbstractCurrent industrial technologies for seawater desalination involve high cost and energy consumption, that is, distillation and reverse osmosis, where these technologies are difficult to implement especially in developing countries. A cost‐effective, environmental‐friendly, and sustainable technology is essential in providing alternative methods for generation of clean water. Solar vapor generation is one of the potential green technologies in generating clean water, where the production and collection of clean water is made possible by using a solar absorber in a solar still. The practicality and performance of the carbonized sawdust based solar absorber in a solar still for the seawater desalination towards clean water generation was conducted outdoors with gradual enhancement on the solar still setup. The enhanced solar still with reflective surface and external thermal insulator improved the solar absorber performance, in contrast to the evaporation of the bulk seawater only and using solar absorber in the solar still without any enhancement. The average efficiency and evaporation rate of the solar absorber in the enhanced solar still was recorded at 61.5% and 0.98 kg m−2 h−1, respectively. The pH (7.52) and salinity (10 ppm) of the collected clean water meets the standard of safe water by the World Health Organization.

Molecular heterostructured interlayer for fabrication of high-performance thin film composite reverse osmosis membranes

To solve the scarcity of fresh water, reverse osmosis (RO) technology for seawater desalination and wastewater reuse has been developed rapidly. However, the performance of RO is limited by poor selectivity towards certain harmful small molecule constituents (e.g., boron in seawater and N-nitrosodimethylamine in wastewater) and the permeability-selectivity trade-off. Herein, a metal polyphenol network interlayer including both hydrophobic zone and monomer adsorption zone is proposed to optimize interfacial polymerization (IP) process for fabrication of RO membrane. This heterogeneous characteristic is endowed by well-chosen phenol (i.e. TTSBI) and metal (Ni). The physicochemical properties of the substrate are also optimized. An ultra-selective RO membrane with thinner separation layer, higher crosslinking degree and larger surface area is obtained. The RO membranes exhibit separation performance beyond the upper selectivity limit for NaCl and hazardous small molecules. The membrane water permeance is 3.50 L m−2h−1bar−1while the NaCl rejection is 99.5 %. Meanwhile, the mechanism of the interlayer influencing IP process is investigated by combining molecular simulation and experimental methods. Our work provides a novel design direction of substrate used for fabricating RO membrane with outstanding performance.

MoS2 supported hydrophilic porous membrane for solar water evaporation

Solar powered interfacial water evaporation has become one of the most direct and sustainable technologies for seawater desalination. However, developing an efficient, stable evaporator with good salt resistance is a critical and challenging. In this work, MoS2-CNT@C membranes synthesized by loading 1T/2H MoS2 flower spheres on the CNT@C hierarchically porous membrane by hydrothermal method are used as solar water evaporators. MoS2-CNT@C membranes, as photothermal conversion materials, have broadband solar absorption capacity and good hydrophilicity. The porous structure of CNT@C membrane can provide great water transport channels, and the decoration of flower spheres MoS2 enhances the internal reflection which can increase the sunlight absorption capacity, resulting in a jump in water evaporation properties. The membrane has a high evaporation rate of 2.53 kg m−2h−1 under one sun illumination. In addition, the evaporation rate of the sample in seawater reaches 2.51 kg m−2h−1, similar to that in the pure water, and remains stable after several evaporation cycles, ensuring that high quality fresh water can be produced during the desalination.

Predicting the boron removal of reverse osmosis membranes using machine learning

Reverse osmosis (RO) is a key technology for seawater desalination, but boron removal remains challenging due to the relatively low and varying boron rejection of RO membranes. This study explored the use of machine learning (ML) to develop predictive models for boron removal of RO membranes. Data of 11 features encompassing membrane properties, testing conditions and membrane performance were collected from journal articles. Missing data were recovered using data imputation algorithms. The predictive models were developed using five regression algorithms: linear, ridge, decision tree, random forest and XGBoost regressors, and the tree-based XGBoost regressor performed the best (R2 = 0.84). Feature importance analysis and tree diagrams revealed that membrane type, feed pH and NaCl rejection as key factors in influencing boron rejection, while membrane surface properties showed minimal impact. Partial dependence plots were generated to further analyze each feature. High NaCl rejection of >99.6 % is highly desirable for SWRO membranes to achieve high boron rejection. For BWRO membranes at pH >9, a looser structure with a NaCl rejection >95 % could be applied. The study successfully applied ML to a dataset with large portion of missing values, and the results provide valuable insights for future membrane design and boron removal processes.

Research on the application of hydrophilic modified covalent organic framework membranes in seawater desalination

Given the global challenge of freshwater scarcity, the importance of seawater desalination technology has grown. This study examines the efficiency and role of hydrophilic-modified covalent organic framework (COF) membranes in seawater desalination through molecular simulations. Incorporating hydrophilic groups like -SO3H into N2COF membranes and optimizing their structure significantly improved water permeability and salt ion retention. Non-equilibrium molecular dynamics (NEMD) simulations showed that hydrophilic modifications enhance water permeability while preserving salt ion interception efficacy. Furthermore, adjusting the membrane's stacking method could further enhance its seawater desalination performance. The simulations confirm the high-efficiency desalination capability of hydrophilic-modified COF membranes and offer crucial theoretical guidance for designing and preparing high-performance desalination materials.

Wind Power Coupled with Seawater Desalination Technology for Hydrogen Production Promotes Sustainable Development of Economy and Environment

In order to guarantee the economies and the environment’s sustainable growth, the development of new energy is essential. This paper discusses and analyzes development and disadvantages of wind power and hydrogen energy, as well as development status and advantages of wind power coupling technology. The technology combines the advantages between the wind power and hydrogen energy. Wind power coupled hydrogen production technology is currently developing rapidly all over the world. It can successfully address a few issues with hydrogen manufacturing and wind energy generating. It can also supply electricity and water. Wind power generating has the potential to gradually refocus development toward offshore wind energy and reliable wind power generation, as well as far-reaching marine wind energy.Green hydrogen can be produced simultaneously using wind power linked hydrogen manufacturing technologies. To reduce the world’s dependence on fossil energy, reduce carbon emissions, and protect the ecological environment.

Carbon Footprint of Seawater Desalination Technologies: A Review

Abstract As an important and effective way of mitigating water shortages, desalination has steadily and rapidly increased its global capacity over the decades. This raises concern about its environmental impacts, especially its carbon footprint (CF). Although the CF of desalination has been extensively studied, the existing literature lacks reviews exclusively for it. To help fill the research gap, this study presents a comprehensive and up-to-date review of the CF of seawater desalination technologies, including the conventional reverse osmosis (RO), multi-stage flash (MSF), multi-effect distillation (MED), electrodialysis (ED), and mechanical vapor compression (MVC), and the emerging membrane distillation (MD) and humidification–dehumidification (HDH). To our knowledge, this is the first review that focuses on the CF of seawater desalination. A general procedure for assessing the CF of a desalination system is discussed. The CF data of 211 scenarios from 34 studies published from 2004 to 2023 are reviewed and analyzed, with special focuses on the CF of different technologies, the roles of different life-cycle phases and material/energy flows, and the mitigation measures. The results highlight the CF advantage of RO and low-carbon heat-driven MSF, MED, and MD, and emphasize the dominant role of the operational energy consumption (the amount, the form, and especially the source of the energy) in the CF of desalination. This review improves the understanding of the CF of seawater desalination technologies and of the ways to reduce it.

Technical analysis of seawater desalination

As the population grows and the economy thrives. The amount of edible water has decreased, and this phenomenon is raising awareness about water supply. Dumping salt into a bucket of water may seem like no big deal, but reversing the process is a lot more complicated than people might think. Seawater desalination technology is also a hot topic of research. There are two major techniques for desalting. One is distillation, and the other is reverse osmosis filtration. This essay mainly discusses how the two techniques work and what benefits human beings can possibly obtain from the future development of such technology based on existing literature and statistical data, namely prosperity. The result shows that the reverse osmosis process uses less energy in comparison to thermal distillation. However, desalination is not as easy as we expected. Regarding energy consumption and cost efficiency, scientists have to maintain high productivity while reducing the impact on the environment.

A PAM hydrogel surface-coated hydroponic bamboo evaporator with efficient thermal utilization for solar evaporation

Solar-driven interfacial water purification emerges as a sustainable technology for seawater desalination and wastewater treatment to address the challenge of water scarcity. Currently, the energy losses via radiation and convection to surrounding environment minimize its energy efficiency. Therefore, it is necessary to develop strategies to minimize the heat losses for efficient water purification. Here, a novel evaporator was developed through the in situ gelation of PAM hydrogel on the surface carbonized hydroponic bamboo (PSC) to promote energy efficiency. The inherent porous and layered network structures of bamboo, in synergy with the functional hydration capacity of PAM hydrogel, facilitated adequate water transportation, while reducing evaporation enthalpy. The PAM hydrogel firmly covered on the photothermal layer surface effectively minimized the radiation and convection heat losses, while further harvesting those thermal energy that would otherwise dissipate into the surrounding environment. The reduced thermal conductivity of PSC served as a thermal insulator as well, obstructing heat transfer to bulk water and thus diminishing conduction losses. Consequently, the rational designed PSC could efficiently convert solar energy to purified water, leading to the evaporation of 2.09 kg m−2 h−1, the energy efficiency of 87.6 % under one sun irradiation, and yielding 9.6 kg m−2 fresh water over 11 h outdoor operation. Moreover, the PSC also performs excellent salt rejection, and long-term stability at outdoor experiment. These results demonstrated high and stable solar evaporation performance could be achieved if turning heat losses into a way of extra energy extraction to further enhance the evaporation performance. This strategy appears to be a promising strategy for effective thermal energy management and practical application.

Optimization of Desalination Efficiency and Exploratory Applications of TiO2 Active Site Electrode Enhanced by Activated Carbon and Tween 80 in Capacitive Deionization Technology.

Capacitive deionization (CDI) is an emerging desalination technology for seawater desalination. The development of high-desalination and long-life electrode materials is a research focus in the global water treatment field. In this experiment, Tween T80 was used as a surface activator, and a modified electrode was prepared by facilitating the deposition of TiO2 active sites onto the surface of activated carbon through a sol-gel/hydrothermal two-step synthesis strategy. The morphology and specific surface area of the composite material were analyzed through scanning electron microscopy, specific surface area measurements, and contact angle tests. The results indicated that the sol-gel/hydrothermal two-step synthesis strategy played a crucial role in the homogeneous combination and performance enhancement of the composite material. Under constant voltage mode, when the working voltage was 1.2 V, the desalination capacity of this composite material in a NaCl solution with an initial conductivity of 3000 μS·cm-1 reached 23.8 mg·g-1 (26% higher than materials prepared by conventional sol-gel methods). After 150 cycles, the capacity retention rate was 78%, and the retention capacity was significant (87%). Overall, the results demonstrate the potential of the sol-gel/hydrothermal two-step synthesis strategy in preparing high-performance CDI electrode materials. The modified electrode prepared using this method offers enhanced desalination capacity and durability, making it a promising candidate for seawater desalination and other water treatment applications.

Integration of Renewable Energy Systems in Desalination

Desalination plants, which provide drinking water for residents, rely on electricity generated by fossil fuels. However, the excessive use of fossil fuels leads to their rapid depletion and has detrimental effects on the environment. Thus, the use of renewable energy resources in water desalination has gained popularity. The current research investigates the integration of renewable energy systems with seawater and brackish water desalination technologies. In this regard, three primary renewable energy sources—wind, solar, and geothermal—are selected. Accordingly, a thorough investigation of the related research published and the trend of evolutions between 2013 and 2023 is carried out for Reverse Osmosis (RO), Multistage flash (MSF), and Multi-effect distillation (MED)-based water desalination facilities coupled with renewable energy sources. In our investigation, we particularly focus on performance indicators, energy efficiency, economic factors, and environmental effects. Also, the associated challenges of these hybrid systems, such as technological complexity, unpredictability, and intermittency, are addressed. Prospects for the future that address these issues and the prospects of using renewable energy in water desalination technologies are also covered.