Search Results (474)

Membrane distillation (MD) technology has become an effective solution to freshwater scarcity due to its low energy consumption, high separation efficiency, and ability to handle highly concentrated saline wastewater. Nevertheless, issues such as membrane wetting, membrane fouling, and low membrane flux severely limit its large-scale application. Composite membranes prepared using metal–organic framework (MOF) materials as fillers have become a research hotspot due to their advantages, such as permeable microporous channels, customizable pore structures, and modifiable active sites. These properties enable them to effectively reduce temperature polarization and concentration polarization phenomena. This article describes the characteristics of MOF materials and their current applications in the field of MD, with a comparative analysis of the applicability of MOF polycrystalline membranes and MOF composite membranes in MD, and discusses the working principle of MOFs in enhancing the performance of MD. Finally, the problems and challenges associated with the use of MOFs in MD applications are analyzed. This study aims to provide theoretical guidance for the application of MOF materials in the field of MD seawater desalination. Full article

Desalination is an urgent response to global freshwater shortages, serving more than 300 million people by 2025. However, it is a technology that still raises several sustainability concerns. Through this study, we aim to propose a systematic review based on the PRISMA methodology, analyzing 45 studies published between 2015 and 2026. Quantitative synthesis of 45 studies showed brine salinity ranging from 40 to 75 g/L, boron and bromate concentrations of 1.8 mg/L and 25 µg/L, respectively, and energy consumption of 3–5 kWh/m³ for membrane systems, reaching 15 kWh/m³ for thermal technologies. Economically, the levelized cost of desalinated water remains high (USD 0.5–2.0/m³) due to the high energy consumption of up to 15 kWh/m³ in thermal processes. This study proposes several mitigation strategies, including diffuser optimization, integration of renewable energies, and brine recovery through the extraction of strategic minerals. The originality of this study lies in its integrated approach, combining health, environmental, energy, and economic dimensions, all addressed together in previous reviews. These results demonstrate the need for regional governance and consistent international standards to achieve sustainable water desalination that combines water security and ecosystem conservation. Full article

To address the high energy demand and product losses associated with separating taurine from sodium sulfate (Na₂SO₄) in the ethylene oxide route to taurine, electrodialytic desalination of a simulated taurine/Na₂SO₄ mother liquor was investigated. The effects of applied voltage, circulation flow rate, and initial feed concentration on the desalination rate, product purity, taurine recovery, current efficiency, specific energy consumption, and membrane productivity were evaluated. Ion-transport behavior was further examined using COMSOL Multiphysics^® 6.3. At 14 V, a circulation flow rate of 200 L/h, and initial taurine and Na₂SO₄ concentrations of 100 and 68 g/L, respectively, the process achieved a taurine purity of 99.8% and a recovery of 98.9%. The specific electrical energy consumption of the electrodialysis unit was 0.56 kWh/kg Na₂SO₄, and the membrane productivity was 0.49 kg Na₂SO₄/(m²·h). One of the key findings of this work is that the low-salt stage plays a dominant role in process economics. This observation led to a simple endpoint-control strategy. The ED operation is stopped when the Na₂SO₄ concentration in the dilute compartment drops to about 2 g/L. This avoids prolonged operation under inefficient conditions and reduces ED energy consumption by 16.5%. Within the binary simulated system and the defined cost boundary, the proposed process provided a higher taurine recovery and a lower estimated separation cost than the conventional crystallization route. These results demonstrate the laboratory-scale feasibility of electrodialysis for desalting simulated taurine mother liquor. Full article

Dissolved bio-essential trace metals (Cu, Zn, Co, Ni, and Fe) in seawater and 17 elements in surface sediments were studied to assess the metal contamination and associated ecological risks in the Sulaibikhat Bay Marine Protected Area (MPA) in the northwestern Arabian Gulf. Dissolved metals were mostly at low to moderate levels and within the limits of most international water quality standards. However, dissolved Cu concentrations (0.54 to 4.73 µg L⁻¹) in the MPA stations (MPA-1 and MPA-2) exceeded the Oslo–Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) ecotoxicological assessment thresholds, suggesting possible adverse ecological effects. Sediment showed higher levels of Cd, Cr, Ni, V, Cu, and Zn at stations within the MPA, with Principal Component Analysis (PCA) linking these enrichments to nearby industrial and desalination discharge sources. The calculated enrichment factor (EF) and geoaccumulation index (I_geo) values confirmed moderate to substantial anthropogenic contributions for Cd, Cr, and Ni, while the major lithogenic elements were derived from natural mineralogical inputs. A pollution load index (PLI) > 1 at stations MPA-1, MPA-3 and MPA-4 in Sulaibikhat Bay indicated cumulative metal contamination. Ecological risk assessment criteria classified sediments within the MPA and Sulaibikhat Bay as having a moderate level of ecological risk, with Cd identified as the principal contributor. The toxicological indices, namely mean Effect Range Median Quotient (m-ERM-Q) and mean Probable Effect Level Quotient (m-PEL-Q), indicated a low-to-moderate probability of adverse biological effects due to Cu and Ni exposure in the MPA. In contrast, the reference station in the Kuwait Bay showed very low contamination and negligible ecological risk. These findings stress the need for continuous monitoring and effective source control to protect the ecosystem of this newly established MPA in Kuwait. Full article

Saudi Arabia is a water-stressed nation and meets much of its daily demand through desalination, an energy-intensive process with a significant carbon footprint. As a Muslim-majority country, residents perform ablution before five daily prayers, making this activity a substantial yet under-quantified component of residential water use. This study focuses on household-level ablution water savings across 13 regions for both Saudi and non-Saudi households by replacing standard taps with a flow rate of 5.7 L/min with a proposed Saudi Standards, Metrology and Quality Organization (SASO)-compliant ultra-low-flow tap (1.9 L/min). Moreover, this study evaluates this ultra-low-flow tap as an environmental technology capable of reducing ablution water consumption and found that per capita savings are identical for both demographic segments, but the total household savings differ because Saudi households are larger, supporting sustainable water management. Results show that under the stated assumptions, full national adoption of the proposed tap would reduce monthly ablution water use from 27 million m³ to 9 million m³, conserving 212.14 million m³ annually with 67% efficiency and offsetting 702,198 tonnes of desalination-related carbon emissions. This highlights the effectiveness of deploying a simple water-saving technology in a water-stressed environment. Conservation potential is concentrated in Riyadh, Makkah, and the Eastern Province due to their high household counts. A four-year phased implementation roadmap is proposed, beginning with 25% adoption in year one (53.01 million m³ annual savings), expanding to moderate-impact regions in year two, and reaching 75–100% adoption nationwide by years three and four. The findings demonstrate how simple and commercially available water-efficient technology can contribute to sustainable resource management by simultaneously reducing water demand, energy consumption associated with desalination, and related greenhouse gas emissions. This study supports Saudi Arabia’s Vision 2030 water strategy and can potentially support UN-SDGs 6, 7, and 13 by demonstrating the substantial water, carbon, and economic benefits of a simple, commercially available tap of 400 SAR. In addition, the study develops a regionally prioritized technology deployment framework that can support decision makers in planning large-scale implementation. The analysis assumes that household members perform ablution five times daily for approximately one minute, based on field measurements, and they require validation of projected gains through actual implementation. Full article

The decarbonization of essential water supply infrastructure is a critical challenge for water-stressed and geographically constrained regions, particularly islands where both water and electricity systems are highly dependent on external or fossil-based resources. In Northern Cyprus, approximately 70% of domestic water demand is met through imported water via pipeline, while electricity generation relies predominantly on fuel oil, resulting in high greenhouse gas emissions and environmental burden. This study evaluates an integrated renewable energy-based supply system using a medium-scale concentrating solar power (CSP) plant with parabolic trough collectors coupled to thermal desalination. The proposed configuration is assessed as an alternative energy-driven infrastructure option for reducing dependence on imported water and fossil-based electricity. System performance was evaluated by estimating electricity and freshwater production under local climatic conditions, demonstrating that the proposed configuration can meet both the associated electrical energy requirements and domestic water demand in the selected region. A cradle-to-gate life cycle assessment (LCA) was conducted to quantify the environmental impacts of the integrated system and support sustainability-oriented decision-making. The LCA results identify residual fossil-based electricity, phosphoric acid consumption, and brine discharge as the main environmental hotspots. Overall, the findings show that CSP-driven desalination can provide a viable and more sustainable option for integrated energy and water supply in water-scarce coastal regions with high solar potential, highlighting its relevance for renewable energy integration, water-energy nexus planning, and resource-efficient infrastructure development. Full article

Capacitive deionization (CDI) is an environmentally advantageous desalination technology that is particularly suitable for the treatment of low- to medium-concentration saline water. Among different electrode materials, carbon materials are widely used due to their good electrical conductivity and high specific surface area, while they suffer from limited ion adsorption capacity. In this study, a cobalt/nitrogen-doped porous carbon fiber composite with Zn-induced porosity (CoNG@V@CNF), where “V” stands for “volatile pore-forming agent”, has been successfully prepared via electrospinning combined with a high-temperature carbonization process. The introduction of trace Co nanoparticles enhances the stability of porous graphene. In addition, N doping contributes to improved wettability and electronic conductivity, and the carbon fiber structure constructs a three-dimensional conductive network, providing fast channels for ion transport. Electrochemical tests show that the specific capacitance of CoNG@V@CNF reaches 252.76 F g⁻¹, demonstrating its superior charge storage capability. Furthermore, this study achieved a high salt adsorption capacity of 58.28 mg g⁻¹ and a competitive desalination rate performance of 1.94 mg g⁻¹ min⁻¹. After 40 cycles of testing, the salt adsorption capacity (SAC) remains at 56.72 mg g⁻¹, demonstrating its high stability during multiple charging and discharging processes. This work provides a new design strategy for developing high-performance CDI electrode materials. Full article

The optimal control of complex energy systems via Bellman’s principle of optimality quickly becomes difficult for high-dimensional, path-dependent dynamics because the state space grows exponentially with each time step. We propose a computationally tractable framework based on hierarchical path-dependency decomposition: (i) graph compression that reduces multi-layer topologies to a single directed flow network; (ii) a diffusion convolutional recurrent neural network (DCRNN) that maps historical trajectories into a finite-dimensional hidden state, approximating the transport of past states without storing full trajectories; and (iii) multi-agent reinforcement learning (MARL) for decentralized local control. By restricting full-path online optimization to a rolling one-step horizon and using temperature and flow rate as sufficient statistics for thermal dynamics, the framework preserves physical fidelity while enabling real-time execution. This reduction is justified because thermal constraints constitute the primary active failure mode in energy systems. We provide a proof sketch showing that the diffusion convolution operation in the DCRNN approximates the Green’s function of the underlying transport equation. Using weather data from Palm Springs, California (a region with moderate path dependency), initial numerical experiments achieve 98.4% correlation with reference solutions, a temperature forecasting mean absolute error (MAE) of 1.23 °C, and mostly subsecond (<1 s) inference times using consumer-grade hardware. Despite the thermodynamic advantages of concentrated solar thermal (CST) systems over conventional photovoltaic panels—higher conversion efficiency and integrated thermal storage—their deployment on factory rooftops remains elusive due to the continuous, real-time control burden they impose. The proposed framework directly addresses this barrier by delivering accuracy comparable to classical controllers (MPC, PID) with latency sufficient for real-time intervention, positioning CST for transition from remote desert locations to distributed industrial sites. Beyond solar-thermal generation, the same hierarchical architecture is applicable to integrated HVAC system control (e.g., using movable mirrors to both produce renewable energy and reduce cooling loads in data centers), energy storage management, desalination plant control, and chemical production optimization—any domain where thermal-hydraulic transport must be regulated under tight safety and latency constraints. The framework demonstrates that trading exact Bellman optimality for data-driven approximations enables a shift from offline simulation to sensor-driven real-time regulation across this broader class of energy systems. Full article

Many Greek islands host geothermal springs whose waters can be desalinated to produce drinking water. Some of these waters contain meaningful concentrations of the valuable Rb⁺ and Cs⁺ ions, which, when extracted from the desalination brine as RbCl and CsCl salts, can yield revenues exceeding the freshwater production costs. We demonstrate the use of reverse osmosis (RO) to produce freshwater and apply theoretical simulations to assess a proven extraction method applied to the RO retentate of geothermal water from Samothrace, characterized by [Rb⁺] = 2.72, [Cs⁺] = 0.55, [K⁺] = 514, [Na⁺] = 3759 (all in mg/L) and pH 6. The extraction method, developed by the authors, relies on ion exchange using a PES-coated Zn-hexacyanoferrate sorbent with high affinity for monovalent cations (no affinity for multi-valent cations), followed by a unique ion-chromatography separation. We show that the production cost remains <25% of the salts’ market price, with ROI of ~4.5 years. Full article

Water is an indispensable resource for the survival of all living organisms on Earth. However, many coastal villages continue to face challenges in accessing potable water, particularly during extended droughts. This comprehensive study evaluates the implementation and performance of a solar desalination system that employs photovoltaic (PV) panels and a parabolic solar concentrator to meet clean water demand in a drought-prone area of Indonesia. The system harnesses both solar-generated electricity and thermal energy to power an advanced desalination apparatus, effectively converting seawater into safe drinking water. Over a rigorous 4-month testing period, the device maintained an average steam outlet temperature of 105.9 °C, enabling a direct single-stage evaporation and condensation desalination process. Under optimal sunlight conditions, the system produced 1500 mL of purified water every 30 min, resulting in a total daily output of approximately 12 L (1500 mL × 8 cycles over 4 h). Laboratory analysis revealed a decrease in pH from 8.0 in raw seawater to 6.8 in treated water after post-treatment pH adjustment, meeting established safety standards for human consumption. Electrical conductivity measurements fell from 40–50 mS/cm to 480–500 µS/cm, confirming substantial salt removal. These results demonstrate the system’s capacity to generate potable water using sustainable energy sources and support circular economy principles by repurposing renewable resources for water desalination in water-scarce environments. Full article

Saltwater batteries can be made using brine from the desalination of seawater for low-cost energy storage. This study investigates the performance characteristics of saltwater batteries for potential off-grid energy applications. The systematic investigation of 15 electrode pairings from six electrodes (copper, iron, zinc, graphite, aluminium, and tin) across eleven concentration levels, combined with studies on electrode geometry, spacing, and volume, provides comprehensive insights into galvanic cell behaviour for saltwater batteries. Results indicate that the open-circuit voltage (OCV) is primarily determined by electrode potential differences rather than salt concentration, with zinc-carbon and aluminium-carbon pairings producing the highest voltages (1.1–1.2 V). Short circuit current increases with salt concentration up to approximately 30% (0.3 M), which is the saturation point, beyond which ion mobility decreases. This study demonstrates that electrode geometry and surface area significantly affect current density and internal resistance, while increased electrode spacing raises internal resistance and reduces maximum current output. These findings contribute to understanding the feasibility and performance characteristics of saltwater batteries as accessible energy sources using recyclable materials. Full article

Strontium (Sr) is a valuable metal that is increasingly utilized in many industries. Due to the numerous problems associated with land-based mining, extracting Sr from seawater and seawater desalination brine has become an alternative option. Among the various methods for recovering Sr from seawater and seawater brines, the adsorption process is particularly attractive. Because seawater contains other metal ions (Na⁺, K⁺, Ca²⁺, and Mg²⁺) at much higher concentrations than Sr²⁺, adsorbents that can selectively remove Sr²⁺ are required. This paper presents a comprehensive and critical review of advanced adsorbents used and their mechanisms for selectively adsorbing Sr²⁺ from seawater and brines. Although these adsorbents remove a higher proportion of Sr²⁺ than other metal ions from seawater, other metals are also adsorbed—some in much larger quantities than Sr²⁺. Therefore, it has not been possible to recover only Sr²⁺ through desorption to produce a high-purity Sr product. Because of its similar valence and chemical hardness, Ca²⁺ competes most strongly with Sr²⁺ adsorption. In this review, an improved method is proposed in which Ca²⁺ and Mg²⁺ are first removed by hydroxide precipitation, followed by repeated adsorption/desorption cycles to progressively increase the proportion of Sr²⁺ relative to other ions in the selective adsorbent until only Sr²⁺ remains adsorbed. At this stage, the adsorbed Sr²⁺ can be desorbed to produce a solution containing only Sr²⁺, from which a high-purity Sr salt can be manufactured. Full article

This paper assesses the role of green hydrogen and green ammonia in the low-carbon reconstruction of Ukraine’s energy sector. The country, severely affected by war, has more than 70% of its energy infrastructure damaged or destroyed, which calls for novel solutions for not only reconstructing but also rethinking Ukraine’s energy sector shaped by the Soviet-era planning. In this context, decentralized and renewable energy solutions appear to be one of the best options to achieve this goal. This study combines four novel and mutually reinforcing methods: a Scopus-based literature review of highly cited green hydrogen publications, natural language processing (NLP) and bibliometric network analysis of Ukraine-related hydrogen research, a SWOT assessment, and a geospatial hydrogen production cost model (GEOH2). The novelty of this research lies in this integrated Ukraine-specific framework, which links research trends, wartime reconstruction constraints, hub-level policy choices, and financing risk-sensitive cost modeling. Therefore, the quantitative part of GEOH2 estimates the levelized cost of green hydrogen, while ammonia is treated as a downstream screening-level conversion and export pathway rather than as a full plant-level ammonia model. Our results show that Ukrainian green hydrogen research is concentrated on renewable-energy strategy, wind and solar electrolysis, water and desalination constraints, gas grid blending, underground storage, ammonia derivatives, and decentralized energy systems. The GEOH2 results indicate that southern Ukraine has strong physical potential for competitive green hydrogen production under de-risked financing, while war risk financing can make even resource-rich areas economically unattractive. Odesa and Dnipro emerge as important export-oriented and industrial hubs, whereas Zakarpattia remains strategically relevant as a safer western corridor linked to European markets. Our findings demonstrate that Ukraine’s hydrogen and ammonia development needs to follow a phased pathway: domestic renewable build-out and grid repair, pilot electrolysis projects and screening-level ammonia conversion pathways, targeted de-risking and insurance mechanisms, and only then broader export corridor development. This pathway can support decarbonization, energy security, industrial modernization, and Ukraine’s long-term integration into European clean energy value chains. Full article

Disinfection of drinking water prevents waterborne diseases but can lead to the formation of trihalomethanes (THMs), which are linked to an increased risk of cancer. This study examined the association between water source allocation and THM levels in Israel. A retrospective analysis of water quality reports, published by the Israeli Ministry of Health, was conducted, including only samples collected from the water distribution system between 2015 and 2024. To assess temporal and geographic variability, monthly and annual averages were calculated. Trends were evaluated using interrupted time series regression. Overall, 16,268 samples were included, with a study-wide mean THM level of 30.41 µg/L, mainly due to Bromoform. Elevated THM levels were observed in northern districts, particularly before 2020, with seasonal peaks in the summer months. After 2020, as surface water utilization increased, THM levels also rose in central Israel, with no discernible seasonal pattern. Southern regions, supplied mainly by desalinated water, showed consistently low levels. This analysis indicates that the water source influences THM formation, as increased surface-water use is associated with higher THM concentrations. Mixing surface and groundwater with desalinated water may reduce exposure in areas with high THM levels, highlighting the need for informed water management policies. Full article

The desalination of brackish and seawater has emerged as a critical strategy to address growing water scarcity in regions experiencing water stress, particularly within the context of sustainable water resource management. Among available technologies, forward osmosis (FO) has gained increasing attention due to its potential for lower energy consumption and reduced environmental impact compared to conventional desalination processes. In this study, commercial HFFO₂ (Aquaporin Inside) membrane from FO was used. A complete factorial design with three factors was used: feed solution concentration (1.5 and 3 g/L NaCl), draw solution concentration (15, 25, and 35 g/L NaCl), and feed solution flow rate (600 and 1000 mL/min) on the percentage of recovery and water flux. Tests showed that as the feed concentration decreases from 3 to 1.5 g/L of NaCl, water recovery improves by 23.6%. The results revealed that increasing the concentration of the draw solution from 15 to 25 g/L of NaCl increased water recovery by 22.2%. However, for a concentration variation of 25 to 35 g/L, this increase is insignificant at 0.92%. The results showed that, with a concentration of 1.5 g/L of NaCl, a feed flow rate of 1000 mL/min, and a concentration of 25 g/L of NaCl as the draw solution, a higher water recovery rate (95.4839%) was achieved. Similarly, average water flux values of 2.18, 2.43, and 2.68 $L{m}^{-2}{h}^{-1}$ were observed when using draw solutions of 15, 25, and 35 g/L of NaCl, respectively. In addition, increasing the FS flow rate slightly reduces water recovery (from 76.04% to 74.06%). Consequently, the forward osmosis process has proven to be effective, practical, viable, and environmentally friendly for water desalination, as well as being applicable to the treatment of wastewater with high electrical conductivity. Full article