Search Results (244)

Seawater desalination has become a critical approach to mitigating the global scarcity of freshwater resources. This study aims to comprehensively review desalination methods based on thermal and electromagnetic methods, examining their processes, benefits, and limitations. Thermal methods include multi-stage flash distillation, multi-effect distillation, thermal vapor compression, and mechanical vapor compression. These techniques rely on evaporation and distillation to remove salts and are effective in treating highly saline water. However, they consume large amounts of energy and are prone to problems such as limescale and corrosion. In contrast, electromagnetic-based technologies represent a novel, promising approach for enhancing desalination performance. Electromagnetic fields contribute to improved membrane performance and equipment longevity by modulating ionic behavior and mitigating surface fouling. Empirical studies suggest that such interventions can lead to reduced energy usage and lower rates of mineral deposition. The findings reviewed here suggest that integrating thermal and electromagnetic techniques may offer a viable pathway toward more sustainable, efficient, and reduced environmental impacts. Full article

Soil salinity poses a major challenge to agricultural productivity, especially threatening food security in arid and semi-arid areas. Traditional soil reclamation methods, such as leaching, chemical amendments, and drainage engineering, usually need large amounts of water, involve high costs, and can lead to environmental problems. This review compiles existing knowledge on innovative strategies for managing saline soils, focusing on buried interlayer systems that use materials like straw, sand, gravel–sand mixtures, and biochar. These interlayers improve soil hydraulic properties by preventing capillary rise, encouraging salt leaching, and reducing surface salt buildup. Biochar stands out as a particularly useful material because of its stability, large surface area, porosity, and high cation exchange capacity. These features help improve soil structure, increase water retention, and effectively retain sodium. Evidence from lab and field tests shows that buried biochar layers can stop salt from moving upward, aid in desalinating the root zone, and boost crop yields. While straw and sand interlayers show potential in reducing salinity, biochar is noted for its multifunctionality and long-term effectiveness in addressing salinity problems. The success of buried biochar systems depends on several factors, including the properties of the biochar, how much is used, how deep it is buried, and the specific soil and climate conditions. This review highlights how these systems work, compares their performance, and points out research gaps, advocating for their potential as a sustainable, resource-efficient way to manage salinity and improve soil health over the long term. A substantial proportion of the existing evidence is derived from controlled laboratory studies, and the buried biochar layer approach remains an emerging technique that requires further validation under field conditions. Still, significant knowledge gaps persist regarding long-term performance and water-salt dynamics, while site-specific soil variability and scalability challenges may limit the effective implementation of biochar interlayer systems under field conditions. Full article

The rising demand for clean water has reinforced the importance of thin-film composite TFC polyamide membranes in desalination and wastewater treatment. While improvements often target the selective layer, these can sometimes reduce stability or selectivity. An alternative approach is to tailor the porous support, particularly through the incorporation of nanomaterials such as metal oxides, carbon-based nanomaterials, metal–organic frameworks (MOFs), zeolites, and cellulose-based materials, to improve overall membrane performance. The modification of membrane substrates through the incorporation of nanofillers has demonstrated notable advantages, including enhanced hydrophilicity, improved mechanical stability, and increased porosity. These improvements collectively contribute to higher permeability, reduced internal concentration polarization and enhanced separation performance in FO, NF, and RO applications. The review starts by clearly distinguishing substrate modification, in which nanomaterials are localized in the porous support, from interlayer modification, which involves constructing a distinct layer between the support and selective layer. This concise review highlights current developments in the nanomaterial-based support modification of polyamide TFC membranes; it summarizes nanomaterials selections, incorporation techniques, and resulting property changes. Current challenges and potential research opportunities are also discussed. Full article

Membrane fouling remains a major obstacle to the performance of the reverse osmosis (RO) desalination processes. Artificial intelligence (AI) is now a promising approach for the reliable modeling of these complex systems. This study evaluates three modeling techniques—multiple linear regression (MLR), artificial neural networks (ANNs), and support vector regression (SVR)—for predicting transmembrane pressure (TMP) at the Boujdour desalination plant, based on five input parameters: temperature, turbidity, pH, conductivity, and feedflow. The analysis is based on an original dataset of 195 daily measurements, and due to the absence of timestamps, the study focuses on state-to-TMP prediction rather than chronological forecasting, with no temporal generalization claimed. Approximately 2000 augmented training samples generated using a conservative SMOGN approach were used for model development, while performance evaluation relied exclusively on 39 independent real test observations. Two modeling strategies were adopted: (i) a minimalist approach based on significant variables identified by an ordinary least squares (OLS) model (pH and conductivity), and (ii) a multivariate approach integrating all parameters to capture non-linear interactions. A rigorous validation framework was put in place to avoid information leakage and ensure the robustness and generalizability of the models. Performance was evaluated using R², RMSE, and MAE metrics, supplemented by robustness and significance analyses including bootstrap confidence intervals, paired statistical comparisons, and interpretability analyses based on permutation importance, partial dependence plots (PDPs), and individual conditional expectation (ICE) curves. The results indicate that the SVR model achieves the best average predictive accuracy among the tested models, albeit with moderate explanatory power. Full article

Desalination is an increasingly important element in the sustainable supply of potable water. To accurately predict costs, the efficiency of such systems requires accurate knowledge of seawater’s thermodynamic properties. Four models have been proposed for determining the thermophysical properties of salt water, pure water, an ideal mixture, and an aqueous sodium chloride solution, and empirical correlations, as would be expected, provide the precision necessary for accurate exergy calculations. This research began with a study of the most recent and accurate empirical investigations of the thermodynamic properties of seawater. It then employed AI techniques to develop a simpler, more accurate model for density, Gibbs free energy, specific enthalpy, and specific entropy for pressures extending up to 12 MPa, salinities from 0 to 80 g/kg, and the temperature range of 10 °C to 120 °C. The AI-based correlations achieved absolute errors of 1.5 kg/m³ for density, 0.185 kJ/kg for specific enthalpy, 0.005 kJ/kg·K for specific entropy, and 0.214 kJ/kg for Gibbs free energy. These values demonstrated at least equivalent, and even superior, accuracy to the existing state-of-the-art formulations, with the advantage of significantly reduced computational complexity, enhanced computational efficiency, and a more user-friendly implementation. Validation against experimental data demonstrated the exceptional accuracy of the predicted values for all the stated thermodynamic properties. In addition, an exergy-based assessment was conducted of the performance of a recently commissioned desalination plant in Kuwait. This was a large-scale multi-effect distillation plant with thermal vapour compression (MED-TVC), showing a second-law efficiency of 8.9%, with the primary source of exergy destruction identified as the evaporator units. Comparative assessment with a more conventional approach showed differences of less than 0.4% in total exergy destruction and less than 5% in exergetic efficiency. This is taken as a validation of the accuracy, reliability, and practical usefulness of the proposed AI framework for the performance evaluation of desalination systems. Full article

Arid zones, such as the MENA regions and the Sahara countries, are experiencing significant water stress. To address this global challenge, desalination technologies provide a crucial solution, particularly the reverse osmosis (RO) technique, which is widely used to treat Seawater or Brackish water. Mauritania is among the countries facing a scarcity of potable water resources and relies on desalination technologies to meet its water demand. In this work, a numerical and experimental study was carried out on the functional and productive parameters of the Nouadhibou desalination plant in Mauritania using MATLAB/Simulink (R2016a). The study considered two operating scenarios: with and without the energy recovery unit. The objective of this paper is to perform an analytical study of the operating procedures of the Nouadhibou RO desalination plant by varying several parameters, such as the pressure exchanger, and the feed water mixing ratio in the pressure exchanger unit, etc., in order to determine the system’s optimal operating point. This paper analyzes the system’s performance under different conditions, including recovery rate, feed water temperature, and PEX splitter ratio. In Case No. 1 (without a pressure recovery unit), and with a recovery rate of 20%, doubling the plant’s productivity from 400 to 800 m³/d requires 400 kW of power. In contrast, in Case No. 2 (with a pressure recovery unit), achieving the same productivity requires only 100 kW, with a 75% of energy saving. When the desalination plant operates at a productivity of 400 m³/d@40%, the SPC decreases from 6 kWh/m³ (Case No. 1) to 2.7 kWh/m³ (Case No. 2), resulting in a 55% specific power consumption saving. The results also indicate that power consumption increases with both feed water temperature and PEX splitter ratio, while variations in these parameters have a negligible effect on permeate salinity. Full article

The area of robot autonomous navigation has become essential for reducing labor-intensive tasks. These robots’ current navigation systems are based on sensed geometrical structures of the environment, with the engagement of an array of sensor units such as laser scanners, range-finders, and light detection and ranging (LiDAR) in order to obtain the environment layout. Scene understanding is an important task in the development of robots that need to act autonomously. Hence, this paper presents an efficient semantic mapping system that integrates LiDAR, RGB-D, and odometry data to generate precise and information-rich maps. The proposed system enables the automatic detection and labeling of critical infrastructure components, while preserving high spatial accuracy. As a case study, the system was applied to a desalination plant, where it interactively labeled key entities by integrating Simultaneous Localization and Mapping (SLAM) with vision-based techniques in order to determine the location of installed pipes. The developed system was validated using an efficient development environment known as Robot Operating System (ROS) and a two-wheel-drive robot platform. Several simulations and real-world experiments were conducted to validate the efficiency of the developed semantic mapping system. The obtained results are promising, as the developed semantic map generation system achieves an average object detection accuracy of 84.97% and an average localization error of 1.79 m. Full article

To scientifically address the low productivity issue of traditional solar desalination systems, the current review intends to investigate the effect of design changes and performance improvement of solar stills with external and internal condensers. This review highlights that elements such as coolant techniques, the geometry of the condenser, and material features (e.g., nanofluids or surfaces of wettability) have a pivotal impact on maximising output. The results show that the combination of external condensers in solar stills is remarkably effective, where the efficiency ranges between 24% and 165% in distillate yield depending on the design modifications, which include the use of nanofluids, reflectors, and phase change materials (PCMs). In this regard, internal condensers explicitly display significant performance advances, with water production improvements of more than 150% in improved stepped designs and 60% in capillary film designs. To guarantee the maximum production of fresh water, this review proposes a number of adjustments to elevate the overall performance of solar stills, such as condensers with enhanced mechanisms of heat transfer or passive cooling strategies, which enable solar stills to be more practical in achieving the sustainable desalination of water across a wide range of climatic regions. Indeed, the enhancement of the efficiency of solar desalination technologies would support the United Nations Sustainable Development Goal 6 (Clean Water and Sanitation), providing access to safe and affordable drinking water for all. Full article

The shortage of freshwater resources and the depletion of fossil fuels have emerged as two pivotal challenges confronting global development. Photothermal membrane distillation (PMD) technology, a technique that harnesses solar energy for seawater desalination, not only produces freshwater but also mitigates the pressure of energy depletion. However, its sole focus on freshwater production no longer meets the demands of the energy market. Based on this, this study proposes a power–water cogeneration system based on PMD and thermal-osmotic energy conversion (TOEC) technology. The system achieves power–water cogeneration by changing the supply side heat source structure of TOEC technology and coupling it with traditional PMD technology. The experimental results showed that under the illumination condition of solar intensity of 4 kW·m⁻² for 3.5 h, the fresh water production and water production rate of the system reached 2.23 g and 1.39 kg·m⁻²·h⁻¹, respectively. Meanwhile, the fresh water output pressure reached 0.91 bar, and the output power density was 0.0456 W·m⁻². This system is expected to provide a new solution to address the global shortage of freshwater resources and the depletion of fossil fuels. Full article

Global freshwater scarcity continues to escalate due to pollution, climate change, and population growth, making innovative sustainable desalination technologies increasingly vital. Solar stills offer a simple and eco-friendly method for freshwater production by utilizing renewable energy, yet their low productivity remains a major limitation. This study experimentally evaluates and quantifies several established enhancement techniques under real climatic conditions to improve evaporation and condensation efficiency. The integration of porous materials, such as black rocks, significantly improves thermal energy storage and management by retaining absorbed heat during the daytime and releasing it gradually, resulting in an average 30% increase in daily distillate production (SD = 6 mL). Additionally, forced convection using small fans enhances humid air removal and evaporation rates, increasing the average yield by approximately 11.4% (SD = 2 mL). Optical concentration through lenses intensifies solar irradiation on the evaporation surface, achieving the highest performance with an average 50% improvement in water output (SD = 5 mL). The incorporation of Phase Change Materials (PCM) is further proposed to extend thermal stability during off-sunshine hours, with materials selected based on a melting point range of 38–45 °C. To minimize nocturnal heat loss, future designs may integrate radiative cooling materials for passive night-time condensation support, by applying a radiative cooling coating to the condenser plate to enhance passive heat rejection to the sky. Overall, the validated combined use of renewable energy-driven desalination, thermal storage media, and advanced strategies presents a practical pathway toward high-efficiency solar stills suitable for sustainable buildings and decentralized water supply systems in arid regions. Full article

Seawater desalination has emerged as a crucial solution for addressing global freshwater scarcity. However, it generates significant volumes of concentrated brine waste. This brine is rich in dissolved salts and minerals, primarily, chloride (55%), sodium (30%), sulfate (8%), magnesium (4%), calcium (1%), potassium (1%), bicarbonate (0.4%), and bromide (0.2%), which are often discharged into marine environments, posing ecological challenges. This study presents a comprehensive global review of innovative technologies for recovering these constituents as valuable products, thereby enhancing the sustainability and economic viability of desalination. The paper evaluates a range of proven and emerging recovery methods, including membrane separation, nanofiltration, electrodialysis, thermal crystallization, solar evaporation, chemical precipitation, and electrochemical extraction. Each technique is analyzed for its effectiveness in isolating salts (NaCl, KCl, and CaSO₄) and minerals (Mg(OH)₂ and Br₂), with a discussion of process-specific constraints, recovery efficiencies, and product purities. Furthermore, the study incorporates a detailed techno-economic assessment, highlighting revenue potential, capital and operational expenditures, and breakeven timelines. Simulated case studies of a 100,000 m³/day seawater reverse osmosis (SWRO) facility demonstrates that a sequential brine recovery process and associated energy balances, supported by pilot-scale data from ongoing global initiatives, can achieve over 90% total salt recovery while producing marketable products such as NaCl, Mg(OH)₂, and Br₂. The estimated revenue from recovered materials ranges between USD 4.5 and 6.8 million per year, offsetting 65–90% of annual desalination operating costs. The analysis indicates a payback period of 3–5 years, depending on recovery efficiency and product pricing, underscoring the economic viability of large-scale brine valorization alongside its environmental benefits. By transforming waste brine into a source of commercial commodities, desalination facilities can move toward circular economy models and achieve greater sustainability. A practical integration framework is proposed for both new and existing SWRO plants, with a focus on aligning with the principles of a circular economy. By transforming waste brine into a resource stream for commercial products, desalination facilities can reduce environmental discharge and generate additional revenue. The study concludes with actionable recommendations and insights to guide policymakers, engineers, and investors in advancing brine mining toward full-scale implementation. Full article

A global transition in water management is currently underway, marked by the declining reliability of conventional sources and the accelerated adoption of non-conventional alternatives. This shift is driven by escalating pressures from climate change, population growth, and freshwater overexploitation. While the literature on management of water sources (WSs) is extensive, empirical clarity on Hybrid Water Systems Management (HWSM)—the integration of conventional and non-conventional WSs within a single system—remains limited. The present study addresses this gap through a systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, which ensures methodological transparency and applicability. From over 9000+ peer-refereed articles retrieved from three major scientific databases (ScienceDirect, Scopus, and Web of Science Core Collections), published between 1999 and 2024, 44 studies were identified as the most relevant and consequently analyzed. The literature review refines the classification of WSs, distinguishing conventional sources, such as groundwater and surface water, from non-conventional alternatives, such as desalinated water, treated wastewater, gray water, and rainwater harvesting. The analysis also indicates that non-conventional WSs are now more prominent in the literature than conventional ones. Overall, the present study demonstrated that modern water management strategies increasingly emphasize optimization and circular reuse. In contrast, earlier approaches tend to focus more on water conservation and economic efficiency. The literature also indicates a gradual shift from traditional supply-dominant models toward integrated, cost-effective, and sustainability-oriented approaches that combine multiple sources and advanced allocation techniques. Full article

Seawater has been widely used in copper–molybdenum flotation plants due to the shortage of fresh water and the high cost of seawater desalination, especially in arid regions. There have been many studies concerning the molybdenite flotation in seawater. Due to the complication of seawater flotation, it is difficult to identify the key factors affecting molybdenite recoveries. It is known that the unique structure of molybdenite plays an important role in molybdenite flotation. The anisotropic property of molybdenite leads to the different surface properties of basal and edge plane surfaces. Electrochemical properties of sulfides have a significant effect on the surface properties which affect the flotation performance. Therefore, it is important to understand the surface electrochemical properties such as surface chemistry, redox processes, and reaction kinetics of molybdenite’s two different surfaces in seawater, and to determine what affects the molybdenite flotation behaviors in seawater. In this study, the surface properties of molybdenite basal and edge plane surfaces in both fresh water and seawater were investigated through various electrochemical techniques. Open circuit potential (OCP) measurement indicated that edge plane surfaces were easier to be oxidized than basal plane surfaces. Cyclic voltammetry (CV) studies showed that the basal plane surfaces were stable with a low electrochemical reactivity, while the edge plane surfaces had relatively high electrochemical reactivity. In addition, the redox property of the molybdenite surface was enhanced in seawater, which is a key to the improvement of fine molybdenite flotation in seawater. Electrochemical impedance spectroscopy (EIS) measurements further confirmed the stability of basal plane surfaces and indicated a greater charge transfer ability of edge plane surfaces in seawater. Different molybdenite particle sizes with different basal and edge ratios were applied in the flotation in both fresh water and seawater; the results illustrated that molybdenite flotation was enhanced in seawater especially to fine particles. The flotation and electrochemical studies reveal that the electrochemical reactivity of edge plane surface plays an important role in molybdenite seawater flotation. Full article

Direct Contact Membrane Distillation–Crystallization (DCMD-Cr) is a synergistic technology for zero liquid discharge (ZLD) and resource recovery from high-salinity brines. In this study, DCMD-Cr was integrated to desalinate real oilfield-produced water (PW) with an initial salinity of 156,700 mg/L. The PW was concentrated to its saturation point of 28 wt.% via DCMD, and the integrated crystallization increased the overall water recovery from 42.0% to 98.9%, with a decline in water flux and salt rejection, mainly due to vapor pressure lowering and scaling. The precipitated salts in the crystallization unit were recovered and identified using different techniques. The results indicated that 91% of the crystals are sodium chloride, and less than 5% are calcium sulfate. A techno-economic analysis (TEA) was performed to evaluate the economic feasibility of the integrated DCMD-Cr process with a 500,000 gallons per day (GDP) capacity. The results showed that the crystallization operating cost was dominant at USD 0.50 per barrel, while the capital cost was only USD 0.04 per barrel. The economic viability can be enhanced by recovering value-added byproducts and using renewable or waste heat, which can reduce the total cost to USD 0.50 per barrel. Full article

Membrane innovations have become a key solution for overcoming the bottlenecks in efficiency upgrade in many green energy fields. Membrane performance depends on two key parameters permeability and selectivity, which typically follow a trade-off relationship: improving one often diminishes the other. Two-dimensional (2D) materials, which have atomic-level thickness, tunable pore sizes, and reasonable functionalization, offer great promises to break through the trade-off effect and redesign high-efficiency mass transfer pathways. This review systematically presents recent efforts in both preparation and potential applications of 2D materials for overcoming the permeability–selectivity trade-off. It highlights four prevailing fabrication strategies: chemical vapor deposition, interfacial synthesis, solution-phase synthesis, and exfoliation, and shows some major optimization techniques for various 2D materials. Additionally, this review discusses emerging applications of 2D materials across critical fields from water treatment (seawater desalination, metal ion extraction) to energy technologies (osmotic power generation, direct methanol fuel cells, and vanadium redox flow batteries). Finally, the challenges and future prospects of 2D materials in ion separation and energy conversion are discussed. Full article