Search Results (97)

Electrochemical treatment can provide contaminant destruction, phase separation, ionic polishing, and resource recovery; however, performance cannot be judged by removal efficiency alone. This structured critical review compares electro-oxidation (EO), electrocoagulation (EC), electro-Fenton (EF), electrodialysis (ED), electrodeionization (EDI), capacitive deionization (CDI), flow-electrode CDI (FCDI), and bioelectrochemical systems (BES) in municipal wastewater, industrial effluents, sludge-related applications, and treatment side-streams. Searches of Scopus, Web of Science Core Collection, and PubMed were updated to 22 July 2026, and the evidence was assessed according to treatment function, wastewater realism, operating mode, durability, residual fate, energy and cost boundaries, resource recovery, and life cycle implications. Recent advances include porous flow-through anodes, oxygen-efficient cathodes, selective ion separation materials, and pilot BES configurations. However, scale-up remains constrained by electrode aging, by-products, sludge and concentrate management, oxygen transfer, fouling, competing ions, internal resistance, biological instability, and incomplete long-term economic and environmental evidence. The quantitative results show that the energy, cost, and carbon outcomes depend strongly on the treatment function and system boundary. The evidence for sludge and biosolids is less mature than that for liquid wastewater. Therefore, electrochemical technologies are best positioned as function-specific units within hybrid treatment trains rather than as universal replacements for conventional treatments. Full article

Concentration polarization is a common phenomenon in membrane separation processes and generally impairs mass transfer efficiency. Electrodialysis (ED) is considered a promising technology for concentrating high-salinity solutions used in air-conditioning systems; however, concentration polarization under high-concentration operating conditions remains insufficiently understood. In this study, a numerical framework combining a simplified model and a coupled transport model was developed to characterize concentration distributions within an ED concentrate channel. The effects of flow velocity, current density, and feed concentration on concentration profiles were systematically investigated. The results show that transmembrane water transport plays an important role in concentration polarization, and neglecting this effect leads to significant overestimation of ion concentration near the membrane surface. Although ion concentration increases markedly in the vicinity of the ion-exchange membranes, it remains nearly constant in the bulk region along the flow direction. Based on this non-uniform concentration distribution, a conceptual ED configuration with separated flow channels was proposed and evaluated. The results indicate that selectively extracting the enriched boundary-layer region can enhance the outlet concentration of the product stream, whereas increasing the intermediate channel width reduces volumetric yield, revealing a clear trade-off between concentration enhancement and production capacity. 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

The increasing pressure on water resources is one of the most critical challenges of the 21st century. Demographic, industrial, and climatic factors are drastically reducing the availability of fresh water, with particularly pronounced effects in arid regions and the Mediterranean basin. Agriculture, which accounts for about 70% of global water withdrawals, is at the centre of this crisis, making it essential to explore unconventional sources such as brackish water. Desalination emerges as a key technology to address this challenge. Electrodialysis offers an attractive alternative, particularly suitable for moderately salty water (1000–5000 mg/L of total dissolved solids), thanks to its energy efficiency within specific salinity ranges and the ability to precisely control the quality of the produced water. At the same time, agrivoltaic systems that integrate energy production and agriculture are spreading, requiring compact, modular treatment devices that can be integrated with renewable sources. This research objective is the design and building of an affordable and reproducible electrodialysis (ED) prototype, equipping the system with automated sensor-based control, validating the device performance on brackish water and analyzing the feasibility of integration in agrivoltaic contexts. Full article

Hexavalent chromium (Cr (VI)) contamination of water resources constitutes a major environmental and public health issue due to its high toxicity, mobility, and carcinogenic properties. This review examines recent advances in Cr (VI) removal technologies from water and wastewater, with emphasis on membrane-based separation processes and adsorption approaches. Conventional treatment methods, including chemical precipitation, ion exchange (IX), electrocoagulation (EC), electrodeionization (EDΙ), bioremediation, and photocatalysis, are comparatively discussed in terms of removal efficiency, operational limitations, and applicability. In parallel, sustainable adsorbent materials derived from biomass and agricultural waste are evaluated as environmentally friendly and cost-effective alternatives for chromium removal. The role of functional groups, adsorption mechanisms, and redox interactions involved in Cr (VI) reduction and immobilization is also analyzed. Attention is given to membrane technologies, such as reverse osmosis (RO), nanofiltration (NF), electrodialysis (ED), and ultrafiltration (UF) after surface modification with the incorporation of nanomaterials and/or the application of Layer-by-Layer (LBL) assembly techniques, which enhance selectivity, permeability, and antifouling behavior. The reviewed studies demonstrate that advanced membrane systems and bio-based adsorbents can achieve high chromium removal efficiencies while supporting sustainable water treatment practices. Overall, the combination of membrane technologies with functionalized materials represents a promising direction for the development of efficient and environmentally sustainable Cr (VI) remediation systems capable of meeting increasingly strict regulatory limits. Full article

Fouling phenomena are among the main issues in membrane processes, worsening unit performance and membrane properties. So far, few modelling approaches have been proposed to predict colloidal fouling in electromembrane-based technologies. This work presents an original simulation platform that couples computational fluid dynamics (CFD) simulations with electrodialysis (ED) and colloidal fouling models to investigate the impact of colloidal deposition at the channel and unit scales of ED systems. Fluid dynamics, salt transport and fouling layer growth were all addressed. The model was calibrated and validated with colloidal fouling data from the literature. The regions more susceptible to fouling growth were identified. Polarization phenomena, as well as the increase in pressure losses and electrical resistance over time, were evaluated. Full article

The poor rehydration capacity of micellar casein (MC) powder due to the tightly cross-linked structure formed by colloidal calcium phosphate (CCP) limits its potential applications. This study aimed to improve the rehydration properties of MC powder by electrodialysis (ED) treatment. After being treated by ED for 0, 10, 30, 60, and 90 min, the casein micelle powder exhibited a reduction in calcium content (25.55 ± 0.08 g/kg to 17.47 ± 0.05 g/kg) with prolonged treatment, corresponding to the progressive dissociation of CCP bridges. Furthermore, the ED treatment significantly increased the solubility of casein micelle powder. Interestingly, after 60 min, the solubility of ED-treated micellar casein plateaued at approximately 80% within 30 min, likely due to modification on protein structure. Therefore, these results indicate that the structure of micellar casein can be modified through ED treatment, leading to improved rehydration properties. Full article

This work proposes a modeling framework based on artificial neural networks (ANN) for the integrated design and dynamic optimization of renewable electrodialysis (ED) systems considering water demand uncertainty, using a first-principles ED model as the data source for the development of the ANN. The optimization goal is to identify the optimal photovoltaic (PV) and battery (BAT) capacities and the optimal time-varying ED voltage and flow profiles during the batch process, considering an uncertain distribution of potential water demand for each batch over an annual operating horizon. This is achieved by minimizing the annual capital and operating costs of the renewable ED-PV-BAT system. The ANN model demonstrated excellent predictive capabilities that closely matched the data generated by the ED model, with ± 3.5–9.6% and ± 2.0–4.8% error margins in the prediction intervals at a 95% confidence level. The optimal design resulting from dynamic optimization exhibited a lower cost than the design attained from the steady-state optimization, as the batch time and energy consumption were 50% and 17% lower, respectively. For this design, the energy consumption and nitrate concentration predicted by the ANN were only 0.31% and 1.2% different from the ED model predictions, without any effects on the predicted costs and batch times. Full article

Traditional thermal concentration processes for LiCl, such as multi-effect evaporation and mechanical vapor recompression (MVR), suffer from drawbacks including high energy consumption and severe equipment corrosion. However, electrodialysis (ED) technology offers several advantages in the concentration process, including high efficiency, energy conservation, selective separation, and the absence of phase-change requirements. This study presents an innovative two-level ED process for efficient LiCl concentration, addressing the limitations of conventional thermal methods. Through systematic small-scale and scale-up experiments, we developed an optimized process achieving exceptional performance. The system attained Li⁺ concentrations of 22.17 g/L in the concentrated solution and 21.17 g/L in the recycled dilute solution, while reducing residual Li⁺ in discharge water to just 1.08 g/L. Remarkably, the process demonstrated significant energy efficiency, with a total consumption of only 85.22 kWh/t LiCl and a minimal water migration amount of 4.21 L/(m²·h). Economic analysis revealed substantial cost savings of 14.66 USD/t LiCl compared to traditional evaporation methods. These findings establish ED as a technically and economically viable solution for industrial LiCl concentration, offering both high efficiency and environmental benefits. Full article

This study investigates electrodialysis (ED) performance for desalination and concentration of monovalent salts (NaCl, NH₄Cl, KCl, and NaNO₃) at varying mass concentrations. Systematic comparisons of current efficiency (η), energy consumption, water loss, desalination rate η_salt, and other key parameters reveal salt-specific behaviors and process determinants. Experimental results show distinct performance hierarchies across operational phases. In the 1% desalination phase, KCl achieved optimal performance with 95.3% salt removal, a dilute η of 99.96%, a production capacity (Q) of 54.95 L/(h·m²), and a unit energy consumption (E_u) of 3.24 kWh/t. This performance outshone that of NaCl (η_salt = 95.2%) and NaNO₃ (η_salt = 89.5%), with NH₄Cl showing the lowest value (80.6%) in this phase. This trend inversely correlated with cation hydration energies. On the other hand, in the 3% concentration phase, NH₄Cl demonstrated superior performance with a concentrate η of 83.49%, a flux of 35.71 L/(h·m²), and the lowest E_u (5.30 kWh/t), despite a lower concentration factor (5.33) than NaNO₃ (6.48). These findings highlight that KCl is ideal for energy-efficient brine treatment (<3% salinity), while NH₄Cl is better suited to high-purity recovery. Although NaNO₃ has a high E_u during concentration, it is favorable for applications where minimizing energy usage is critical. Full article

The increasing global demand for sustainable water management in coal-fired power plants highlights the critical challenges of high-salinity wastewater treatment, where electrodialysis technology emerges as a promising technology for salinity removal. This paper systematically investigates the application status, technical principles, advantages, and challenges of electrodialysis (ED) in clean water treatment for coal-fired power plants, and its future development potential is also discussed. As an efficient membrane-based desalination technology, ED could effectively remove chloride ions, sulfate ions, and other dissolved salts from clean water, significantly reducing conductivity and enabling both water reuse and salt recovery. Studies indicate that through optimized operational parameters and system design, ED systems can achieve over 90% desalination efficiency and concentrate salts to levels exceeding 12%, delivering notable economic and environmental benefits. However, practical implementation still faces challenges such as membrane fouling and high energy consumption. Advances in novel membrane materials, system integration, and intelligent control technologies are expected to broaden ED’s applicability in power plant water treatment. This study serves as a valuable technical reference for advancing clean water purification and resource recovery in the energy sector, and the findings will contribute to informed decision-making for sustainable water treatment solutions. Full article

This study introduces a two-step treatment method for synthetic and real electric arc furnace dust (EAFD) wastewater, integrating sorption with Mg–Al layered double hydroxides (LDHs) and electrodialysis (ED). The hydrotalcite (LDH), mainly Mg₆Al₂(CO₃)OH₁₆·4H₂O (hydrotalcite-2H), was characterized by XRD, FTIR, SEM, and EDX, confirming its layered structure and ion-exchange capacity. Calcination at 550 °C was identified as optimal, enhancing sorption efficiency while retaining rehydration potential. Sorption tests demonstrated high effectiveness in removing multivalent ions, achieving over 99% elimination of Ca²⁺, SO₄²⁻, and Pb²⁺ ions and Cr from both synthetic and real wastewater. In contrast, monovalent ions such as Na⁺ and K⁺ were not effectively removed, except for partial removal of Cl⁻. To overcome this limitation, electrodialysis was applied in the second step, successfully targeting the remaining monovalent ions and achieving more than 95% conductivity reduction. A key challenge of ED, salt precipitation caused by calcium and sulphate in the concentrate, was effectively mitigated by the prior LDH treatment. The combined process minimized scaling risks, improved overall ion removal (above 97% for Na⁺ and K⁺), and produced low-salinity effluents (0.84 mS cm⁻¹), suitable for reuse in hydrometallurgical operations. These findings demonstrate that coupling LDH sorption with electrodialysis provides a sustainable and efficient strategy for treating high-salinity industrial wastewaters, particularly those originating from EAFD processes. Full article

Amid concurrent pressures on water and material resources, recovering valuable ions like lithium and nutrients from brines and wastewater is a critical tenet of the circular economy. This review provides a critical assessment of electro-driven membranes (EDMs) as a key technology platform for achieving this goal with high energy efficiency. A comprehensive synthesis and analysis of the current state-of-the-art of core EDM technologies, including electrodialysis (ED) and membrane capacitive deionization (MCDI), is presented, focusing the analysis on the performance metrics of specific energy consumption and ion selectivity. The findings reveal that the optimal EDM technology is highly application-dependent, with MCDI excelling for dilute streams and ED for concentrated ones. While significant advances in monovalent selective membranes have enabled lithium recovery, achieving high selectivity between ions of the same valence (e.g., Li⁺/Na⁺) remains a fundamental challenge. Moreover, persistent issues of membrane fouling and scaling continue to inflate energy consumption and represent a major bottleneck for industrial-scale deployment. While EDMs are a vital technology for ion resource recovery, unlocking their full potential requires a dual-pronged approach: advancing materials science to design novel, highly selective membranes, while simultaneously developing intelligently integrated systems to surmount existing performance and economic barriers. Full article

In this study, the integrated process of reverse osmosis (RO) and electrodialysis (ED) is developed to concentrate the dilute solution of acetic acid (HAc). The key parameters, such as RO pressure, ED voltage, and ED volume ratio, were systematically evaluated and the operation conditions of the processes were optimized. Under an operating pressure of 5 MPa, RO can enrich low-concentration HAc from 1.5 wt.% to 6.5% wt.% and the energy consumption is 0.37 kW·h·kg⁻¹. Next, RO-concentrated water was used as the ED feed and the first ED with a volume ratio of the concentrated to dilute chamber of 1:4 was carried out under the conditions of a flow rate of 30 L/h and an operating voltage of 12 V; the HAc concentration reached 12.50 wt.%. The second ED with a volume ratio of 1:5 made the final HAc concentration reach 19.02 wt.%. This study shows that using RO-concentrated water instead of initial water for the ED process can reduce water energy consumption and cost markedly, and the RO–ED integrated process can efficiently pre-enrich low-concentration HAc aqueous solution, and the enriched HAc concentration meets the requirements for the further distillation of HAc. Full article

To fulfil the goals of the circular economy, the treatment of textile wastewater should be focused on the recovery of valuable components. Monovalent anion-selective electrodialysis (MASED) was applied for the separation of reactive dyes from mineral salts. Standard cation-exchange membranes (CM membranes) and monovalent selective anion-exchange membranes (MVA membranes) were used in the electrodialysis (ED) stack. The separation efficiency was evaluated for model solutions of various reactive dyes (varying in molecular weight and chemical reactivity) containing NaCl. In the course of MASED, the mineral salt was successfully removed from the dye solutions with an efficacy of 97.4–99.4%, irrespectively of the composition of the treated solution. The transport of dye molecules through the ion-exchange membranes (IEMs) from diluate to concentrate compartments was irrelevant. Nonetheless, a significant adsorption of dye particles on the membranes was observed. Around 11–40% of the initial dye mass was deposited in the ED stack. Dye adsorption intensity was significantly affected by dye reactivity. This study showed the potential of the MASED process for the separation of the reactive dye from the mineral salt on condition that antifouling membrane properties are improved. The obtained streams (the concentrate rich in mineral salt and the diluate containing the reactive dye) can be reused in the dye-house textile operations; however, some loss of dye mass should be included. Full article