The development of advanced electrode materials is critical for improving the efficiency and durability of capacitive deionization (CDI) technologies for water desalination and separation processes. In this work, a novel conductive hydrogel based on agarose (Aga), tannic acid (TA), and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was designed, optimized, and evaluated as a functional coating for CDI electrodes. The hydrogel formulation was systematically optimized by varying the TA and PEDOT:PSS contents, identifying an optimal composition containing 10 wt% TA and 20 wt% PEDOT:PSS. This formulation exhibited a favorable combination of mechanical robustness, high porosity (~93%), well-distributed pore size, preserved swelling capacity, and enhanced electrochemical properties. Electrochemical characterization revealed improved cathodic stability and capacitive behavior, supporting enhanced ion storage and transport. When implemented in CDI cells, the hydrogel-coated electrodes demonstrated significantly enhanced salt adsorption capacity and higher charge efficiency compared to conventional activated carbon (AC) electrodes. Although the initial salt adsorption capacity was slightly lower than that of other soft-coated electrodes, the gel-based system showed progressive performance improvement and superior long-term cycling stability during aging tests. The enhanced hydration, facilitated ion transport, and sustained structural integrity contributed to improved operational efficiency and durability. Overall, the proposed Aga-TA-PEDOT:PSS hydrogel represents a promising electrode material for energy-efficient, stable, and scalable CDI systems, with potential applications in low-salinity and brackish water treatment. • Conductive Aga-TA-PEDOT:PSS hydrogels developed as CDI electrode coatings. • Optimized hydrogel shows high porosity and mechanical stability. • Gel-coated electrodes enhance ion transport and adsorption efficiency. • Superior cycling stability achieved compared to bare carbon electrodes. • Hydrogel electrodes improve CDI efficiency with potential energy savings.

The sustainable management of seawater reverse osmosis (SWRO) brines remains a critical issue for desalination processes and acquires increasing significance at larger scale. In addition to disposal challenges, these brines offer opportunities for resource recovery and circular economy implementation. Increasing brine concentration can facilitate both volume reduction and the extraction of valuable components. This study evaluates, at pilot scale, an integrated brine concentration process combining osmotically assisted reverse osmosis (OARO) technology with a conventional RO pre-concentrator stage, using real seawater RO (SWRO) brine pre-treated by nanofiltration. System performance, energy efficiency and operational behaviour were assessed to identify feasible operating ranges and optimal conditions. Final brine concentrations of up to 245 g/L were achieved, while overall water recoveries varied between 72 and 85%. Specific energy consumption ranged from 7 to 14 kWh/m 3 of permeate production and 18–56 kWh/m 3 of concentrated brine. Optimal performance was identified at target concentrations of 210–230 g/L, providing a balance between recovery, energy demand and process stability. Membrane temperature limitations (≤40 °C) defined the practical operating range and were identified as a key factor influencing system performance. The results confirm that OARO is an energy-efficient and scalable technology for SWRO brine concentration. This experimental validation under unique real conditions supports the integration of OARO in advanced brine management and resource recovery strategies. • Pilot-scale evaluation of OARO technology for real SWRO brine concentration. • Integrated RO–OARO system (28–59 m 3 feed/d) achieved up to 245 g/L brine salinity. • Overall water recovery between 72 and 85% with stable operation. • SEC values of 7–14 kWh/m 3 of permeate and 18–56 kWh/m 3 of brine. • OARO enables energy-efficient and scalable SWRO brine concentration.

Synthesis and physical properties characterization of artificial seawater samples.

Membrane distillation is promoted as a thermally driven desalination process capable of utilizing low grade heat, yet its full thermal and hydraulic burdens have not been comprehensively resolved. The cooling burden is often neglected altogether, an assumption rarely met in real applications and especially in severe water stressed regions. This study develops a lumped thermodynamic framework that quantifies heating, cooling, and pumping duties across three representative membrane distillation configurations. Results show that cooling loads can reach the same order of magnitude as heating, up to 80–100% of the thermal input in open-loop feed setups, and remain of comparable magnitude even with internal or external heat recovery. Pumping penalties of 0.2–0.5 kWh/m 3 are unveiled starting from typical single-pass recoveries of only 2–6% and pressure losses of 300 mbar, underscoring the need for joint thermal–hydraulic optimization. The analysis also suggests a techno-economic trade-off: lowering specific energy consumption requires efficient heat utilization, typically achieved through effective system-level integration, large modules, minimization of terminal temperature differences, and internal or external heat recovery solutions; whereas compact designs entail modest capital expenditures but disproportionately high operational expenditures. Finally, a methodology for translating classical energy requirement indicators into actual energy consumption values is presented. The analysis compares different heating and cooling strategies, showing that feasibility relies not only on “free” heat availability, but also on effective heat sinks, optimized heat recovery, and low-resistance module hydraulics. • Cooling demand reaches 80–100% of heating in some membrane distillation configurations. • Cooling availability, not only heat supply, often constrains membrane distillation system feasibility. • Regardless of the configuration, single pass water recovery does not exceed ~10%. • Thermodynamic energy requirements differ from actual system consumptions. • In membrane distillation, “free” heat alone does not guarantee viability.

Produced water, major byproduct of oil production, presents significant environmental challenges due to its volume and toxicity. Effective management through re-injection is the most environmentally and economically viable approach, yet inorganic scale precipitation from incompatible water mixing poses a critical challenge. Compatibility investigations are essential to understand scale types and quantities before substantial investments, with reaction kinetics playing a pivotal role. This study examines the impact of reaction time on scale precipitation in produced water management, relevant to desalination processes such as pre-treatment and brine disposal. Water samples from two oil-producing fields were mixed, with field facilities allowing either immediate reinjection or 14-day retention. Precipitated scales were filtered from one container after 1 day and from another after 14 days under operational conditions. Results showed that scales filtered after 1 day exceeded 500 mg/L, while those after 14 days were below 150 mg/L, indicating over 350 mg/L of scales re-dissolved into the liquid phase. SEM-EDX analysis revealed that some scales increased in precipitation after 14 days, while others re-dissolved. These findings highlight the critical role of chemical reaction kinetics in scale precipitation, offering insights for optimizing pre-treatment and re-injection systems, enhancing scale management and environmental sustainability in produced water treatment.

This study reports the development of a novel thin-film nanocomposite (TFN) reverse osmosis (RO) membrane with a surface functionalized using graphene oxide (GO) and polydopamine (PDA). GO was synthesized using a modified Hummers’ method and integrated into a PDA-coated commercial RO membrane. The membranes were treated with UV light for varying durations to enable crosslinking of GO nanoparticles to the membranes. The modified membranes showed improved pure water permeability (PWP) and salt rejection compared to the pristine membrane. The resulting RO membrane, which was exposed to 60 min of UV and contained 0.02 g of GO, achieved the best performance, with a PWP of 23.8 L m−2 h−1 bar−1 and a salt rejection of 96%. Antiscaling and antifouling properties were notably enhanced, as indicated by stable flux under silica scaling and decreased bacterial growth. These results suggest that PDA-GO functionalization is a promising approach for improving membrane durability and efficiency in desalination processes.

A multifunctional biomass-derived three-dimensional solar evaporator constructed from wasted herbal medical slag for efficient steam generation and water purification.

A major societal issue that needs an innovative and sustainable approach to freshwater production is the global water scarcity problem. Traditional desalination processes have limitations, such as high energy costs, empirically-supported membrane fouling issues, and low selectivity rates. However, a new approach using nanotechnology may help address many of these problems. Molecular and atomic scale treatments for water can produce higher permeabilities and salt rejection efficiencies through the use of enhanced nano-membranes when using nanomaterials like graphene, nanotubes, and polymer nanocomposites. Examples of mechanisms used in ion removal through nanostructuring include adsorption, sieve-like, and electrochemical interactions. Other examples of improving energy savings through using nanomaterials include capacitive deionization and nanofiltration processes. Challenges associated with nanotechnology are scale-up, cost of production, and the long term stability of the nanomaterials; nonetheless, additional investigation will provide further knowledge regarding the environmental health effects due to leaching of nanomaterials. A life cycle assessment is crucial for a safe and sustainable application of these products and remains an important factor affecting large scale adoption of nanotechnology enabled desalination systems over traditional desalination technologies by being more energy efficient; further study between laboratory results and actual application will help close that gap.

Desalination plays a crucial role in addressing freshwater scarcity resulting from the rising population, industrial expansion, and the impacts of climate change. It employs various technologies tailored to varying levels of salinity. While energy efficiency is a primary focus in desalination, its intuitive interpretation is challenging due to process variations. This viewpoint offers a thermodynamics-based understanding of energy consumption by examining it in terms of irreversible dissipation and minimal separation energy. This study examines the relationship between exergy variations across different desalination technologies, which provides insight into the minimum separation energy and serves as a basis for classifying desalination processes. Simultaneously, particular emphasis is placed on capacitive deionization (CDI) as an emerging desalination technology that requires only incremental advancements to overcome current limitations associated with high feed-water salinity and the restricted desalination capacity of conventional carbon-based electrodes. The integration of advanced battery materials, including sodium-ion and chloride-ion battery systems, with CDI represents a promising strategy to enhance deionization efficiency, thereby enabling the development of higher-performance desalination technologies.

Enhancing water resource recovery: Ozone-ultrafiltration-forward osmosis process for simultaneous tannery wastewater treatment and seawater desalination

The increasing scarcity of freshwater resources underscores the strategic importance of seawater desalination. However, optimizing reverse osmosis (RO) systems remains challenging because of raw water variability, high energy consumption, and membrane degradation. This study investigates the use of artificial intelligence (AI) for predictive monitoring of the Cap Djinet desalination plant (Boumerdès, Algeria), based on real operational data. Six supervised learning algorithms, linear regression (LR), polynomial regression (PR), support vector regression (SVR), random forest (RF), extreme gradient boosting (XGBoost), and multilayer perceptron (MLP), were evaluated for predicting the physicochemical and chemical parameters of the produced water. The findings indicate that ensemble models, particularly XGBoost (R2 = 0.999; RMSE = 6.11; MAPE = 2.23%), outperform other methods, followed by RF and SVR. Although simple, the LR model demonstrated strong robustness (R2 = 0.999; RMSE = 4.90), making it suitable for daily operation. The analysis further indicates that the performance of complex models, such as the MLP, is strongly influenced by the limited sample size (MAPE = 65.45%), illustrating the sensitivity of deep learning approaches in small-data contexts. While this frames the applicability of the results within the scope of the available dataset, it remains representative of the operational conditions commonly encountered in desalination plants with restricted yet meaningful datasets. Overall, XGBoost, RF, SVR, and LR demonstrate significant potential for predictive monitoring and sustainable optimization of desalination processes.

Nanofluidic ion transport, traditionally governed by charge-induced electrical double layers (EDLs), has enabled diverse applications in energy conversion, sensing, and ion sieving. However, such transport is intrinsically passive as it relies on static interface charges. Inspired by biological ion channels, which utilize dynamic interface charges to drive active ion pumping in chloroplast thylakoid membranes during photosynthesis, we demonstrate a photo-induced, active bionic ion transport system. This is achieved using an ultrathin nanofluidic membrane constructed from triazine-based covalent organic frameworks (COFs). The nanofluidic membrane is fabricated via confined interface polymerization, yielding a free-standing, large-area, ultrathin (∼40 nm) structure with robust mechanical properties (Young's modulus ∼1.9 GPa). Light induces a dynamic interface charge change and a photoelectric effect that break ionic thermodynamic equilibrium, thereby stimulating active ion transport with ultrafast sensitivity (response time <1 s) and a high ion transport rate (∼6 × 106 ions/s) and achieving a nanofluidic electrokinetic energy conversion (power density >1 mW/m2). The mechanisms underlying dynamic ion transport and active ion pumping are systematically elucidated and experimentally validated. This work demonstrates the potential of COF membranes for applications in areas such as ionic photodetectors, energy conversion systems, field-effect nanofluidic devices, and desalination processes.

Hydrogen production via water electrolysis using desalinated seawater offers a sustainable energy solution and has attracted considerable attention in recent years. However, its efficiency depends heavily on the quality of water. Many studies have not explored the relationship between treated water quality and hydrogen generation efficiency at each stage of the seawater desalination process. This study examines a three-step seawater desalination process comprising softening with ballasted flocculation (SBF) as a pretreatment, reverse osmosis (RO) as the main desalination step, and ion exchange as a polishing step to provide high-quality water for electrolysis. Water from each purification stage was supplied to the electrolyzer to compare the impact on water quality and hydrogen generation efficiency. The SBF process removed magnesium (Mg) and calcium (Ca) from seawater, as well as turbidity and bacteria, but hydrogen production via water electrolysis continued for no more than 10 h. However, when feeding RO water and RO water processed by ion exchange after the SBF process, hydrogen was generated stably and continuously for 70 h, achieving high efficiency comparable to that of commercial pure water. High production of green hydrogen by water electrolysis is possible through RO seawater desalination combined with SBF pretreatment.

Directional Solvent Extraction (DSE) is a promising desalination process that can produce fresh water from saline water using low-temperature heat sources. Amines, fatty acids, and ionic liquids were proposed as potential directional solvents—these solvents and seawater form liquid–liquid binary mixtures in a two-phase immiscible system. The energy and exergy analyses of the DSE desalination processes require accurate and consistent thermodynamic properties of these liquid–liquid mixtures. This paper presents a systematic framework for evaluating the thermodynamic properties of two-phase, liquid–liquid immiscible binary solutions consisting of seawater and a potential directional solvent. The property prediction framework includes two main steps: (1) a fundamental Gibbs free energy equation is utilized to evaluate the thermodynamic properties of the pure liquid solvent, while pure water and seawater properties were determined using existing correlations; and (2) The Non-Random Two-Liquid (NRTL) excess Gibbs energy model was used membranes to capture deviations of water–solvent mixtures from ideal solution behavior. The thermodynamic properties of two-phase immiscible mixtures of seawater and octanoic acid as a directional solvent were then determined using the methodology described in this paper. Finally, the thermodynamic properties of liquid–liquid immiscible mixtures of octanoic acid and seawater were used to analyze a basic example of a DSE desalination system.

• NMR relaxation time variation reflects solar evapotranspiration of porous media. • Precipitated crusty/patchy salts are characterized by NMR and MRI/SEM imaging. • Salt crust formed inside layered porous media hinders capillary water transport. • Activation energy of confined brine among pores is determined from T 2 curve shift. Salty water transport and evaporation-induced salt precipitation are of vital importance for sustainable desalination and saline agriculture processes. However, there are limited physical insights into capillary transport of saline water, solar-driven interfacial evaporation and salt precipitation in opaque and heterogeneous porous media. To probe solar-driven evapotranspiration dynamics of salty wet porous media, in-situ magnetic resonance characterization is conducted under continuous day and night cycles by monitoring shifts in transverse relaxation time T 2 and imaging cross-sections. Our findings indicate that the crusty salt grows with saline water evaporation from tight porous media, and it blocks the vapor escape to the ambient air while T 2 distribution shifts towards the left. As for coarse porous media, the growth of patchy salt takes place at the free surface of the porous media while T 2 distribution shifts towards the right. More interestingly, crusty salt precipitation has been observed at the interface of fine and large particles in layered porous media with coarse one on the top. By analyzing the fluctuations in T 2 distribution owing to periodic solar heating, we can even determine the activation energy of confined brine in homogeneous or heterogeneous porous media. Our in-situ characterization results unveil the intertwined transport physics of solar-driven interfacial evaporation and salt precipitation for broad water-energy-agriculture nexus applications.

Abstract This study aims to develop the most optimal vacuum control system in a vacuum chamber in a thermal desalination process based on the principle of multi-effect distillation (MED). In this initial study, the method used is an experimental method by varying the feed water flow rate. To facilitate adjustment, a vacuum pump will be installed in each chamber and before entering each chamber, a connecting tank will also be installed to prevent steam from being directly sucked by the vacuum pump which will be controlled by a solenoid valve. The controller component uses a Wisner REX-CH102 and the DAQ system uses a Wellpro WP3084. A control mechanism will be built in each chamber to regulate pressure using data acquisition (DAQ). Test results show that the control system responds to pressure fluctuations caused by feed water injection dynamically, with a relatively small measurement deviation (&lt;1.0%). The resulting vacuum pressure pattern resembles a sawtooth curve, which reflects the opening and closing cycles of the solenoid valve to stabilize the pressure. Following the successful development of the vacuum pressure control system, further research can proceed by integrating boiler steam flow to assess overall MED-based seawater distillation performance.

Current insights and future outlooks of energy-efficient desalination plants: A comprehensive bibliometric analysis

Incorporating corrosion design constraints in desalination process optimization: A case study in mechanical vapor compression

Minimizing the thermal energy use of membrane distillation with real-time operating controls

Life cycle assessment of membrane-based seawater desalination combined with brine resource recovery.