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We report threshold collision induced dissociation experiments on protonated water clusters thermalized at low temperature for sizes n = 19–23. Fragmentation cross sections are recorded as a function of the collision energy and analyzed with a statistical model. This model allows us to account for dissociation cascades and provides values for the dissociation energies of each cluster. These values, averaging around 0.47 eV, are in good agreement with theoretical predictions at various levels of theory. Furthermore, the dissociation energies show a trend for the n = 21 magic and n = 22 anti-magic numbers relative to their neighbours, which is also in agreement with theory. These results provide further evidence to resolve the disagreement between previously published experimental values. A careful quantitative treatment of cascade dissociation in this model introduces interdependence between the dissociation energies of neighboring sizes, which reduces the number of free fitting parameters and improves both reliability and uncertainties on absolute dissociation energies deduced from experiments. [ABSTRACT FROM AUTHOR]

Water dissociation on TiO2 surfaces has been known for decades and holds great potential in various applications, many of which require a proper understanding of thermal transport across the TiO2–H2O interface. Molecular dynamics (MD) simulations play an important role in characterizing complex systems' interfacial thermal transport properties. Nevertheless, due to the imprecision of empirical force field potentials, the interfacial thermal transport mechanism involving water dissociation remains to be determined. To cope with this, a deep potential (DP) model is formulated through the utilization of ab initio datasets. This model successfully simulates interfacial thermal transport accompanied by water dissociation on the TiO2 surfaces. The trained DP achieves a total energy accuracy of ∼238.8 meV and a force accuracy of ∼197.05 meV/Å. The DPMD simulations show that water dissociation induces the formation of hydrogen bonding networks and molecular bridges. Structural modifications further affect interfacial thermal transport. The interfacial thermal conductance estimated by DP is ∼8.54 × 109 W/m2 K, smaller than ∼13.17 × 109 W/m2 K by empirical potentials. The vibrational density of states (VDOS) quantifies the differences between the DP model and empirical potentials. Notably, the VDOS disparity between the adsorbed hydrogen atoms and normal hydrogen atoms demonstrates the influence of water dissociation on heat transfer processes. This work aims to understand the effect of water dissociation on thermal transport at the TiO2–H2O interface. The findings will provide valuable guidance for the thermal management of photocatalytic devices. [ABSTRACT FROM AUTHOR]

The reverse electrodialysis heat engine (REDHE) represents a transformative innovation that converts low-grade thermal energy into salinity gradient energy (SGE). This crucial form of energy powers reverse electrodialysis (RED) reactors, significantly changing wastewater treatment paradigms. This comprehensive review explores the forefront of this emerging field, offering a critical synthesis of key discoveries and theoretical foundations. This review begins with a summary of various oxidation degradation methods, including cathodic and anodic degradation processes, that can be integrated with RED technology. The degradation principles and characteristics of different RED wastewater treatment systems are also discussed. Then, this review examines the impact of several key operational parameters, degradation circulation modes, and multi-stage series systems on wastewater degradation performance and energy conversion efficiency in RED reactors. The analysis highlights the economic feasibility of using SGE derived from low-grade heat to power RED technology for wastewater treatment, offering the dual benefits of waste heat recovery and effective wastewater processing. [ABSTRACT FROM AUTHOR]

The Electrodialysis with Filtration Membrane (EDFM) system has shown promise in juice enrichment, but further optimization is needed. This study evaluated the effect of processing duration (3 and 6 h) on juice composition, process efficiency, and membrane fouling. Results demonstrated a significant impact of processing time on juice composition, especially anthocyanin and mineral content. Two anthocyanin-depleted juices (−18.94% and −30.70%) and two anthocyanin-enriched juices (26.21% and 44.21%) were produced. Similar energy (1512.13 Wh/g of anthocyanins) was required to migrate equivalent amounts of anthocyanins over both time periods, with no impediment due to fouling observed, although the system's resistance increased (2.5-fold after 3 h, 3.2-fold after 6 h). Membrane fouling was characterized through conductivity, thickness, ATR-FTIR, SEM-EDX, and foulant identification. Minimal anthocyanin accumulation occurred on cation-exchange membranes (CEM), while anthocyanins and PACs concentrated within the filtering layer of filtration membranes (FM). However, fouling did not increase with longer processing. Structural alterations were noted in anion-exchange membranes (AEMs), suggesting instability under high electric fields. Overall, EDFM effectively enriched cranberry juice with anthocyanins, but further research is necessary to address AEM degradation under limiting current density conditions. [ABSTRACT FROM AUTHOR]

Desalination brine can negatively impact the marine environment in several ways, although there are ongoing discussions regarding the severity and magnitude of environmental effects. A fascinating strategy to lessen any adverse effects is to undertake resource recovery from the brine, which also has the potential for additional revenue generation. More recently, the increasing demand for secure and less geographically restricted sources of precious or rare earth minerals, integrated with growing awareness of waste management and environmental sustainability, is driving the development of economically viable technologies to recover valuable materials from waste streams. This article provides an overview of different methods and technologies, including reverse osmosis (RO), electrodialysis (ED), and distillation, that can be used to recover precious materials, including Li, Mg, Na, and Rb and valuable blends from various waste sources and thus create a more sustainable and circular economy. The mechanisms are discussed in detail, including electrochemical processes (electrolysis, ED, and capacitive deionization), thermal desalination (multistage flash distillation and membrane distillation), pressure‐driven desalination (RO and nanofiltration), and microbial desalination cells. Challenges associated with recovering precious materials from waste streams, such as fouling, scaling, and environmental impact, along with further research directions and potential applications of desalination technologies, are also addressed. [ABSTRACT FROM AUTHOR]

This study aims to optimize ammonium removal from NH4Cl‐enriched groundwater at different concentrations using an electrodialysis (ED) process. A customized design (CD) based on response surface methodology (RSM) was employed to develop predictive models and improve the performance of the demineralization system. Ion removal efficiency was evaluated in 32 unique experimental configurations, taking into account variations in three input parameters: voltage (A), initial ammonium concentration (B) and demineralization rate (C). These parameters were selected for their impact on two response variables: electric conductivity (Y1) and final ammonium concentration (Y2). An in‐depth analysis of variance (ANOVA) was performed to examine the variables and their interactions. The results indicated that Y1 was significantly influenced by C, while Y2 was influenced by B. In addition, the predictive models demonstrated strong correlations, with a coefficient of determination (R2) greater than 0.88 for both response variables. The RSM approach applied to optimize the parameters studied identified the following optimum values: 14.17 V for A, 1 mg/L for B and 70 % for C, giving Y1 of 215.377 μS/cm and Y2 of 0.279 mg/L. [ABSTRACT FROM AUTHOR]

Industry, agriculture, and a growing population all have a major impact on the scarcity of clean‐water. Desalinating or purifying contaminated water for human use is crucial. The combination of thermal membrane systems can outperform conventional desalination with the help of synergistic management of the water‐energy nexus. High energy requirement for desalination is a key challenge for desalination cost and its commercial feasibility. The solution to these problems requires the intermarriage of multidisciplinary approaches such as electrochemistry, chemical, environmental, polymer, and materials science and engineering. The most feasible method for producing high‐quality freshwater with a reduced carbon footprint is demanding incorporation of industrial low‐grade heat with membrane distillation (MD). More precisely, by using a reverse electrodialysis (RED) setup that is integrated with MD, salinity gradient energy (SGE) may be extracted from highly salinized MD retentate. Integrating MD‐RED can significantly increase energy productivity without raising costs. This review provides a comprehensive summary of the prospects, unresolved issues, and developments in this cutting‐edge field. In addition, we summarize the distinct physicochemical characteristics of the membranes employed in MD and RED, together with the approaches for integrating them to facilitate effective water recovery and energy conversion from salt gradients and freshwater. [ABSTRACT FROM AUTHOR]

BACKGROUND: This work studied the treatment of a synthetic sphalerite acid mine drainage (AMD). The treatment was carried out by means of a previous concentration stage using electrodialysis, followed by electrodeposition using a bioelectrochemical system (BES). RESULTS: The best concentration results were obtained when operating the electrodialysis at 8 V and at a diluate/concentrate volume ratio of 3. This treatment yielded a concentrate fraction of about 25% of the volume and a clear fraction of about 75% of the volume. The concentrated fraction was treated in a BES for the electrodeposition of the metal contained. By operating a microbial fuel cell (MFC), the spontaneous reactions took place and, in 2 days, all the Fe3+ was reduced to Fe2+; then, all the Cu2+ was electrodeposited as pure Cu0 in about 8 days. The maximum current density attained in this stage was 0.1 mA cm−2 and the maximum power was 0.05 W cm−2. Then, a subsequent operation of a microbial electrolysis cell (MEC) allowed for the simultaneous recovery of the Fe2+, Ni2+, Zn2+, and Cd2+ as a mixed metal mass. CONCLUSION: The electrodialysis yielded a clear effluent representing 75% of the total volume and a concentrated effluent accounting for 25%. It was possible to treat the concentrated effluent in an MFC, recovering pure Cu0 with a net electricity generation. The non‐spontaneous metal reductions were subsequently accomplished by means of MEC, the electricity requirements being lower than those in the case of the raw AMD due to the higher mass transfer rate and the reduction of the Ohmic loses. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In this paper, a method is proposed for the complex treatment of technical waste water containing essential concentrations of organomineral impurities including 1 g/dm3 of copper ions. Plasma treatment decreases the chemical oxygen demand of a solution by 17 times, the content of salts by 34%, and the copper and iron concentration by 20%. Electrodialysis decreases the total salt content from 3 to 0.2 g/dm3 and brings the copper and iron content to 8 and 3 mg/dm3, respectively. The destruction of organic substances contained in the water under plasma treatment results in a carbon-containing precipitate studied by physicochemical methods to determine structural and sorption characteristics. The FTIR spectrum of the carbon-containing precipitate indicates the presence of hydrophilic groups and a great amount of uncompensated active sites and free radicals, which can be used in sorption processes. The prospects of using the carbon-containing precipitate as a filler for the desalination chambers of an electrodializer under electrical field application is shown. [ABSTRACT FROM AUTHOR]

In nature, efficient and selective ion transport is facilitated by ion‐conductive channels in cell membranes; these channels reveal an architectural design with specialized functionality. Drawing inspiration from this, mechanistic insights into the angstrom‐scale‐channel membrane composed of ionic‐crosslinked polybenzimidazole and sulfonated poly(ether ether ketone), exhibiting functional differentiation and efficient ion‐sieving properties are presented. Nanochannels allow for strong hydrogen‐bonding interactions with hydrated ions of higher polarity, while rendering significant electrostatic charge effects that impede the transition of multivalent ions by compressing effective passageways. Both hydrogen bonding and electrostatic interactions synergistically result in high selectivity for monovalent ions over multivalent ions because the latter requires overcoming higher energy barriers for transport compared with the former, thereby causing varying extents of ion dehydration within the nanochannels. The resulting membrane achieves a high monovalent ion permeation rate of 1.35 mol m−2 h−1 with a high mono/multivalent ion selectivity of 56.5 for K+/Mg2+ and 286 for K+/Al3+. [ABSTRACT FROM AUTHOR]

Fermentative volatile fatty acid (VFA) production is a sustainable approach for waste valorization. However, selective product recovery remains challenging due to the range of VFAs produced and their dilute concentrations, requiring energy‐intensive purification. Membrane‐based electrochemical separations comprise an energy‐efficient and continuous platform for small molecule separations. At the same time, there is a lack of suitable ion‐exchange membranes for separating between structurally similar organic acids. Here, bicontinuous polyelectrolyte complex (PEC)‐layered nanofiltration membranes are designed for the selective recovery of VFAs using redox‐mediated electrodialysis. Hydrophobic modification of polyelectrolytes via aza‐Michael addition precisely tunes the complexation‐induced phase separation behaviors and the assembled nanostructures. Surface‐confined layer‐by‐layer complexation generates a nanoscale bicontinuous PEC active layer with tailored surface properties that is inaccessible through bulk complexation. Redox‐mediated electrodialysis using the nanostructured membrane exhibits enhancement of both ion permeability and selectivity toward VFAs, with notable reduction of energy consumption by up to 80% compared to conventional electrodialysis. Treatment of synthetic and cow manure fermentation effluents showcases 2 to 4‐fold enrichment of VFAs and simultaneous removal of co‐existing organic acids, with an energy consumption as low as 1.5 kWh kg−1. These findings advance the understanding of interfacial complexation‐induced phase separation of polyelectrolytes and the development of next‐generation nanostructured membranes for multicomponent separations. [ABSTRACT FROM AUTHOR]

The power output of reverse electrodialysis (RED), an important renewable energy technology, can be improved using high-salinity feed solutions. Herein, a RED stack of ultrathin ion exchange membranes was operated continuously for 10 days using reverse osmosis brine (~0.9 M NaClequivalent) and underground water (~0.01 M NaClequivalent). The net power and net energy efficiency were initially 1.8 W m−2cell pair and 40.8%, respectively, and then decreased gradually, as did the generated current and stack resistance. This deterioration was caused not by conventional membrane fouling but by trapped water inside the polymer matrix of the anion exchange membrane, especially near the cathode. The high salinity gradient and ultrathin membranes caused a flux imbalance between co-ion transport and osmotic water permeation. Further, bulk mass transfer was enhanced inside the RED stack to maintain electroneutrality. Therefore, combinations of membranes with high water permeability and permselectivity may be required to achieve stable RED operation. [ABSTRACT FROM AUTHOR]

Sub‐nanoporous membranes with ion selective transport functions are important for energy utilization, environmental remediation, and fundamental bioinspired engineering. Although mono/multivalent ions can be separated by monovalent ion selective membranes (MISMs), the current theory fails to inspire rapid advances in MISMs. Here, we apply transition state theory (TST) by regulating the enthalpy barrier (ΔH) and entropy barrier (ΔS) for designing next‐generation monovalent cation exchange membranes (MCEMs) with great improvement in ion selective separation. Using a molecule‐absorbed porous material as an interlayer to construct a denser selective layer can achieve a greater absolute value of ΔS for Li+ and Mg2+ transport, greater ΔH for Mg2+ transport and lower ΔH for Li+ transport. This recorded performance with a Li+/Mg2+ perm‐selectivity of 25.50 and a Li+ flux of 1.86 mol ⋅ m−2 ⋅ h−1 surpasses the contemporary "upper bound" plot for Li+/Mg2+ separations. Most importantly, our synthesized MCEM also demonstrates excellent operational stability during the selective electrodialysis (S‐ED) processes for realizing scalability in practical applications. [ABSTRACT FROM AUTHOR]

Heavy metal ions can be introduced into the water through several point and non-point sources including leather industry, coal mining, agriculture activity and domestic waste. Regrettably, these toxic heavy metals may pose a threat to both humans and animals, particularly when they infiltrate water and soil. Heavy metal poisoning can lead to many health complications, such as liver and renal dysfunction, dermatological difficulties, and potentially even malignancies. To mitigate the risk of heavy metal ion exposure to humans and animals, it is imperative to extract them from places that have been polluted. Several conventional methods such as ion exchange, reverse osmosis, ultrafiltration, membrane filtration and chemical precipitation have been used for the removal of heavy metal ions. However, these methods have high operation costs and generate secondary pollutants during water treatment. Biosorption is an alternative approach to eliminating heavy metals from water that involves employing eco-friendly and cost-effective biomass. This review is focused on the heavy metal ions contamination in the water, biosorption methods for heavy metal removal and mathematical modeling to explain the behaviour of heavy metal adsorption. This review can be helpful to the researchers to design wastewater treatment plants for sustainable wastewater treatment. [ABSTRACT FROM AUTHOR]

For the upcycling of waste polyethylene terephthalate (PET), encompassing both colored and fabric PET materials, we investigated the Ir(triNHC)‐catalyzed dehydrogenative coupling of PET and methanol, leading to the production of sodium lactate with good yields. We proposed a sustainable method for isolating lactic acid from the catalytic reaction mixture of sodium lactate and regenerating the base using bipolar membrane electrodialysis (BMED). This isolation method demonstrated high effectiveness, achieving isolation of lactic acid while maintaining economic feasibility at $ 0.10 per kg of lactic acid, and enabling sustainable NaOH regeneration with complete resource circulation. We assessed the recyclability of the catalyst and elucidated the mechanism involving base‐mediated depolymerization and catalyst‐promoted dehydrogenation, highlighting the importance of triNHC ligands in enhancing catalytic activity. [ABSTRACT FROM AUTHOR]

Blue energy obtained by salinity gradient can be generated by mixing two saline solutions having different salt concentrations. According to researchers working in this area, about 80% of the current global electricity demand could potentially be covered by this energy source. There are basically two membrane technologies so-called pressure-retarded osmosis (PRO) and reverse electrodialysis (RED) that are capable to generate electrical energy from salinity gradient. The pressure driven PRO process is more suitable for energy generation from highly concentrated brines. However, RED is more favorable for power generation by mixing seawater and river water. In RED process, ion exchange membranes (IEMs) placed between two electrodes in a stack were employed for transport of ions. Thus, an electrical current is obtained at the electrodes by electron transport through redox reactions. This review gives an overview of RED as a pioneering technology for salinity gradient energy (SGE) generation. The review summarizes the recent improvements of IEMs employed for RED studies, membrane fouling and RED stack design. [ABSTRACT FROM AUTHOR]

Laboratory tests were conducted for the production of high-purity perrhenic acid using a membrane technique—electrodialysis. Four solutions were used in the tests: diluate, concentrate, anolyte, and catholyte. The experiments were carried out in a two-stream system. The influence of basic process parameters, including the flow rate of process streams or current density, on the purity of the obtained perrhenic acid were examined. Electrodialysis was also carried out as part of this research, aiming to concentrate the perrhenic acid >100 g/dm3. The concentrate solution obtained in the concentration tests, with a concentration of 148.7 g/dm3 HReO4 and 530 mg/dm3 NH4+, was then sent to the purification process using the electrodialysis method. The purification process was carried out until the concentration of NH4+ ions was <100 mg/dm3 in the concentrate. Finally, perrhenic acid was obtained with the following composition: 169.7 g/dm3 HReO4 and 70 mg/dm3 NH4+. Based on this research, a technological scheme for producing high-purity HReO4 by electrodialysis was developed. [ABSTRACT FROM AUTHOR]

Salinity gradient energy presents a promising opportunity for renewable energy, gaining significant interest in the sustainable power sector. This article presents an overview of the application of ion exchange membranes and reverse electrodialysis techniques to harness energy from salinity gradients in seawater, employing anthropomorphic terminology to enhance understanding. The main focus lies in the utilization of ion exchange membrane technology for power generation, with a particular emphasis on its current implementation status and underlying operational principles. The research aims to enhance readers' comprehension of salinity gradient energy in seawater and promote awareness of "energy security" through the use of descriptive language. [ABSTRACT FROM AUTHOR]

The challenge of efficiently extracting Li+ from brines with high Na+ or Mg2+ concentrations has led to extensive research on developing highly selective separation membranes for electrodialysis. Various studies have demonstrated that nanofiltration membranes or adsorbents modified with crown ethers (CEs) such as 2-OH-12-crown-4-ether (12CE), 2-OH-18-crown-6-ether (18CE), and 2-OH-15-crown-5-ether (15CE) show selectivity for Li+ in brines. This study aims to develop high-performance cation exchange membranes (CEMs) using CEs to enhance Li+ selectivity and to compare the performance of various CE-modified membranes for selective electrodialysis. The novel CEM (CR671) was modified with 12CE, 18CE, and 15CE to identify the optimal CE for efficient Li+ recovery during brine electrodialysis. The modification process included polydopamine (PDA) treatment and the deposition of polyethyleneimine (PEI) complexes with the different CEs via hydrogen bonding. Interfacial polymerization with 1,3,5-benzenetricarbonyl trichloride-crosslinked PEI was used to create specific channels for Li+ transport within the modified membranes (12CE/CR671, 15CE/CR671, and 18CE/CR671). The successful application of CE coatings and Li+ selectivity of the modified membranes were verified through Fourier-transform infrared spectroscopy, zeta-potential measurements, and electrochemical impedance spectroscopy. Bench-scale electrodialysis tests showed significant improvements in permselectivity and Li+ flux for all three modified membranes. In brines with high Na+ and Mg2+ concentrations, the 15CE/CR671 membrane demonstrated more significant improvements in permselectivity compared to the 12CE/CR671 (3.3-fold and 1.7-fold) and the 18CE/CR671 (2.4-fold and 2.6-fold) membranes at current densities of 2.3 mA/cm2 and 2.2 mA/cm2, respectively. At higher current densities of 14.7 mA/cm2 in Mg2+-rich brine and 15.9 mA/cm2 in Na+-rich brine, the 15CE/CR671 membrane showed greater improvements in Li+ flux, approximately 2.1-fold and 2.3-fold, and 3.2-fold and 3.4-fold compared to the 12CE/CR671 and 18CE/CR671 membranes. This study underscores the superior performance of 15CE-modified membranes for efficient Li+ recovery with low energy demand and offers valuable insights for advancing electrodialysis processes in challenging brine environments. [ABSTRACT FROM AUTHOR]

The technological progress and consumerism trend stimulate electric and electronic equipment replacing, inducing the generation of huge amounts of wastes, many of them containing dangerous (but valuable) waste printed circuit boards (WPCBs). A promising technology for their recycling is based on the electrochemically regenerable Br-/Br2 leaching system, for which the raw materials can be produced and recycled by electrochemical ways. In this context, the present work presents our research concerning the feasibility to produce by electrodialysis, on-site, HBr and KOH, which are required for the electro-hydrometallurgical recovery of metals from WPCBs. For this purpose, a four-compartment filter-press electrochemical reactor, divided by two cation and one anion exchange membranes, was used. The obtained results demonstrate that the proposed process can produce, at a current density of 4 kA/m², target solutions with concentrations over the required value (of 0.5 M), with average current efficiencies over 73% and 82%, and average specific energy consumptions around 40 and 25 kWh/kg for HBr and KOH, respectively. Moreover, several preliminary measurements performed simultaneously with the electrodialysis tests revealed that, by acquiring rigorous temperature data, the concentrations of the target solutions can be easily and rapidly evaluated and monitored on-line using simple electrochemical sensors for pH and conductivity, but more accurate and exhaustive calibration data is required. [ABSTRACT FROM AUTHOR]

Natural salinity gradients are a promising source of so-called blue energy, a renewable energy source that utilizes the free energy of mixing for power generation. One promising blue energy technology that converts these salinity gradients directly into electricity is reverse electrodialysis (RED). Used at its full potential, it could provide a substantial portion of the worlds electricity consumption. Previous theoretical and experimental works have been done on optimizing RED devices, with the latter often focusing on precious and expensive metal electrodes. However, in order to rationally design and apply RED devices, we need to investigate all related transport phenomena─especially the fluidics of salinity gradient mixing and the redox electrolyte at various concentrations, which can have complex intertwined effects─in a fully functioning and scalable system. Here, guided by fundamental electrochemical and fluid dynamics theories, we work with an iron-based redox electrolyte with carbon electrodes in a RED device with tunable microfluidic environments and study the fundamental effects of electrolyte concentration and flow rate on the potential-driven redox activity and power output. We focus on optimizing the net power output, which is the difference between the gross power output generated by the RED device and the pumping power input, needed for salinity gradient mixing and redox electrolyte reactions. We find through this holistic approach that the electrolyte concentration in the electrode rinse solution is crucial for increasing the electrical current, while the pumping power input depends nonlinearly on the membrane separation distance. Finally, from this understanding, we designed a five cell-pair (CP) RED device that achieved a net power density of 224 mW m-2 CP-1, a 60% improvement compared to the nonoptimized case. This study highlights the importance of the electrode rinse solution fluidics and composition when rationally designing RED devices based on scalable carbon-based electrodes.

The interactions between molecules and electrode surfaces play a key role in electrochemical processes and are a subject of extensive research, both experimental and theoretical. In this paper, we address the water dissociation reaction on a Pd(111) electrode surface, modeled as a slab embedded in an external electric field. We aim at unraveling the relationship between surface charge and zero-point energy in aiding or hindering this reaction. We calculate the energy barriers with dispersion-corrected density-functional theory and an efficient parallel implementation of the nudged-elastic-band method. We show that the lowest dissociation barrier and consequently the highest reaction rate take place when the field reaches a strength where two different geometries of the water molecule in the reactant state are equally stable. The zero-point energy contributions to this reaction, on the other hand, remain nearly constant across a wide range of electric field strengths, despite significant changes in the reactant state. Interestingly, we show that the application of electric fields that induce a negative charge on the surface can make nuclear tunneling more significant for these reactions. [ABSTRACT FROM AUTHOR]

Abstract This paper presents an in-depth investigation into the optimization of rare earth element (REE) separation through electrodialysis, leveraging a newly developed Class II phenomenological model. This study explores the pivotal roles of the HEDTA/Nd molar ratio and pH of feed solution on enhancing the separation efficiency of neodymium (Nd) and praseodymium (Pr) from lanthanum (La) and cerium (Ce). By integrating expanded Nernst-Planck equations and the concept of limiting current density, the model offers a sophisticated understanding of ion transport dynamics and the impacts of concentration polarization. Experimental validation confirms the model’s predictive accuracy, demonstrating its practical applicability for industrial-scale operations. The research delineates how operational parameters such as chelating agent concentration and pH critically influence the purity and yield of separated REEs. The dynamic nature of chelation chemistry is also examined, highlighting its evolution during the electrodialysis process and its effect on the system’s overall performance. Key findings illustrate that lower HEDTA/Nd molar ratios significantly enhance the purity of Nd + Pr by minimizing the chelation of La and Ce, thus facilitating their migration to the concentrate compartment. Conversely, higher ratios maximize yield by retaining more Nd + Pr in the feed compartment. This dual approach allows for optimized separation based on specific industrial requirements. The outcomes of this study not only advance the field of REE separation but also provide a framework for further research into more efficient and sustainable extraction methods. The developed model and its validation represent a step forward in the practical application of electrodialysis in REE processing, offering substantial benefits for the critical materials sector.

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This paper presents an in-depth investigation into the optimization of rare earth element (REE) separation through electrodialysis, leveraging a newly developed Class II phenomenological model. This study explores the pivotal roles of the HEDTA/Nd molar ratio and pH of feed solution on enhancing the separation efficiency of neodymium (Nd) and praseodymium (Pr) from lanthanum (La) and cerium (Ce). By integrating expanded Nernst-Planck equations and the concept of limiting current density, the model offers a sophisticated understanding of ion transport dynamics and the impacts of concentration polarization. Experimental validation confirms the model’s predictive accuracy, demonstrating its practical applicability for industrial-scale operations. The research delineates how operational parameters such as chelating agent concentration and pH critically influence the purity and yield of separated REEs. The dynamic nature of chelation chemistry is also examined, highlighting its evolution during the electrodialysis process and its effect on the system’s overall performance. Key findings illustrate that lower HEDTA/Nd molar ratios significantly enhance the purity of Nd + Pr by minimizing the chelation of La and Ce, thus facilitating their migration to the concentrate compartment. Conversely, higher ratios maximize yield by retaining more Nd + Pr in the feed compartment. This dual approach allows for optimized separation based on specific industrial requirements. The outcomes of this study not only advance the field of REE separation but also provide a framework for further research into more efficient and sustainable extraction methods. The developed model and its validation represent a step forward in the practical application of electrodialysis in REE processing, offering substantial benefits for the critical materials sector. [ABSTRACT FROM AUTHOR]

Research on proton exchange membrane water electrolysis for renewable hydrogen production is rapidly advancing worldwide, driven by the imperative to reduce costs and enhance efficiency through development of novel materials. However, to effectively evaluate and validate these advancements, standardized testing methods are essential, extending beyond single-cell analysis to encompass stack-level characterization. This paper proposes comprehensive characterization methods tailored for analysis of electrolysis stacks and their performance characteristics. Each method is introduced with a focus on its practical applicability, accompanied by detailed procedural guidelines for implementation. Furthermore, variations within each method are discussed, offering possibilities for gathering additional insights. Presenting a portfolio of different methods, ranging from standard to advanced techniques applicable at the stack level, the paper showcases results obtained through their application. These results, normalized to cell area, demonstrate the significance of each method in obtaining stack characteristics crucial for informed design decisions on material selection and subsequent integration into electrolysis systems. By illustrating results derived from various stacks, this study contributes valuable insights for evaluating design, material suitability, and operational performance, thereby advancing the development and deployment of proton exchange membrane water electrolysis technology for sustainable hydrogen production. • Development of benchmarking and testing protocols for PEM water electrolysis. • Utilization of cyclic voltammetry for assessing degradation effects in electrolysis stacks. • Experimental analysis of system and stack loss mechanisms. • Identification of key elements monitor degradation effects on stack and system level. [ABSTRACT FROM AUTHOR]

Methods for obtaining high-purity perrhenic acid (with metallic impurities content below 100 ppm) of a high concentration > 200 g/dm3 and entirely from secondary raw materials were compared. Comparative analyses of three methods were performed: electrodialysis, solvent extraction (research carried out directly as part of the Small Grant project acronym RenMet), and ion-exchange (developed as part of previous projects implemented by Łukasiewicz-IMN). The basic process parameters were selected as comparative indicators: efficiency and selectivity of the process, purity of the obtained product, availability and consumption of raw materials and reagents, equipment necessary to carry out the process, the profitability of the technology, and the ecological aspects, i.e., the possibility of managing the generated solid waste and post-production solutions. Analysis of the verified indicators allowed us to select the most economically and ecologically advantageous method of obtaining high-purity perrhenic acid from secondary raw materials. Its preparation using the ion-exchange method emphasizes the product's purity and the process's simplicity, using readily available waste materials and renewable ion-exchange resin, and is based on a sustainable circular economy. [ABSTRACT FROM AUTHOR]

The shape of nanochannels plays a crucial role in the ion selectivity and overall performance of reverse electrodialysis (RED) systems. However, current research on two-dimensional nanochannel shapes is largely limited to a few fixed asymmetric forms. This study explores the impact of randomly shaped nanochannels using dimensionless methods, controlling their randomness by varying their length and shape amplitude. The research systematically compares how alterations in the nanochannel length and shape amplitude influence various system performance parameters. Our findings indicate that increasing the nanochannel length can significantly enhance the system performance. While drastic changes in the nanochannel shape amplitude positively affect the system performance, the most significant improvements arise from the interplay between the nanochannel length and shape amplitude. This compounding effect creates a local optimum, resulting in peak system performance. Within the range of dimensionless lengths from 0 to 30, the system reaches its optimal performance at a dimensionless length of approximately 25. Additionally, we explored two other influencing factors: the nanochannel surface charge density and the concentration gradient of the solution across the nanochannel. Optimal performance is observed when the nanochannel has a high surface charge density and a low concentration gradient, particularly with random shapes. This study advances the theoretical understanding of RED systems in two-dimensional nanochannels, guiding research towards practical operational conditions. [ABSTRACT FROM AUTHOR]

Sub-Saharan Africa, and in particular Mozambique, has considerable potential of salinity gradient energy, which could foster coastal development. However, the lack of scientific based information hinders the development of policies and investments in harnessing this source of energy in Sub-Saharan Africa. The present study, used historical data of temperature and salinity and estimated the potential of salinity gradient power in four main estuaries in Mozambique. The theoretical salinity gradient power ranged, on average, from 843.6 MW, in Incomati River estuary to 2,800.0 MW in Zambezi Delta. The Bons Sinais Estuary and Limpopo Estuary had 1,086.8 MW and 1292.0 MW, on average, respectively. The salinity power estimated in the Mozambique estuaries studied was above the maximum power densities for electrodialysis osmotic energy storage systems, which is set at 5 W m−2, and has potential extractable energy of about 3,000MW, and could benefit about 2 million coastal rural households (about 7% of the total Mozambican population) on irrigation and lighting houses. Further studies may be focused in determining the seasonal and salinity intrusion effects on salinity power gradient in the Mozambican estuaries. [ABSTRACT FROM AUTHOR]

Electrochemical devices allow the conversion and storage of renewable energy into high‐value chemicals to mitigate carbon emissions, such as hydrogen production by water electrolysis, carbon dioxide reduction, and the electrochemical synthesis of ammonia. Independent regulation of the electrode pH environment is essential for optimizing the electrode reaction kinetics and enriching the catalyst species. The in situ water dissociation (WD, H2O→H++OH−${{{\mathrm{H}}}_2}{\mathrm{O}} \to {{{\mathrm{H}}}^ + } + {\mathrm{O}}{{{\mathrm{H}}}^ - }$) in bipolar membranes (BPMs) offers the possibility of realizing this pH adjustment. Here, the design principles of high‐performance polymeric BPMs in electrochemical device applications are presented by analyzing and connecting WD principles and current–voltage curves. The structure–transport property relationships and membrane durability, including the chemical and mechanical stability of the anion‐ and cation‐exchange layers as well as the integrality of the interfacial junction, are systematically discussed. The advantages of BPMs in new electrochemical devices and major challenges to break through are also highlighted. The improved ion and water transport in the membrane layer and the minimized WD overpotential and ohmic loss at high current densities are expected to facilitate the promotion of BPMs from conventional chemical production to novel electrochemical applications. [ABSTRACT FROM AUTHOR]

Phosphorus, P, is a vital element of paramount importance for both humans and for the Environment. Wastewater contains often relatively high concentrations of P which can be recovered as crystalline struvite (MgNH4PO4·6H2O, MAP). This option is quite attractive in assisting sustainable development because struvite can be used as a slow-release fertilizer. Domestic wastewater is usually high in P and nitrogen, N, but relatively poor in magnesium, Mg. It is necessary to develop low-cost solutions for the enrichment of wastewater with Mg. In the present work, sacrificial magnesium anodes were used, which dissolve upon anodic polarization, releasing sufficient magnesium for the selective precipitation of MAP. The application of constant current between two electrodes of which the anode is a low-cost magnesium cylindrical rod (4 cm2 exposed surface area) and the other a platinum cathode electrode, both immersed in ammonium phosphate solutions, without adjustment of the solution pH, was investigated. Constant current density over the range 10–100 A·m−2, between the Mg- Pt electrodes immersed in solutions of ammonium hydrogen phosphate of exactly known initial concentration, was applied using a potentiostat. In the presence of sodium chloride solutions, on the magnesium anode and in the bulk solution, Mg(OH)2 (brucite) formed because of the passivation of the Mg electrode. In dilute ammonium hydrogen phosphate solutions, the magnesium anode dissolution resulted in struvite precipitation, even at a low applied current (10 mA). Struvite crystals with an average size of 20 μm were precipitated. The behavior of the cell for the electrolyte solutions used was Faradaic as long as the surface coverage of the anode was relatively low. The anodic dissolution of Mg resulted in high pH values (pH 11) eliminating the need for alkali addition. [ABSTRACT FROM AUTHOR]

In the climate changing context, hydrogen is leading the energy transition path. The present work focuses on the green hydrogen production exploiting salinity gradients via Reverse Electrodialysis (RED), in short-circuit condition (RED SC), and Assisted RED (ARED), studied for the first time in hydrogen production as an improvement of the low current densities generated by RED. An extensive experimental campaign was carried out by feeding a RED stack with different salinity gradients and testing short-circuit-RED and Assisted RED operative conditions. Hydrogen was produced successfully with ∼100 % Faradic Efficiency (FE) and productivity up to 1.7 mol h−1 m−2. Also, the technology was compared with similar technologies and with the most established state-of-the-art electrolysers to identify advantages and disadvantages of the proposed route. Finally, a preliminary economic analysis was carried out and a minimum Levelized Cost of Hydrogen (LCOH) of 3.2 € kg−1 H2 was found, thus leaving room for further studies. [Display omitted] • Green hydrogen production from salinity gradient by Reverse Electrodialysis • Production boosting via Assisted Reverse Electrodialysis (A)RED for the first time • Investigation of hydrogen production under different operating conditions • Comparison of the proposed electrolyser with the state-of-the-art • Preliminary economic assessment with calculation of the Levelized Cost of Hydrogen [ABSTRACT FROM AUTHOR]

In recent years, the energy generated by the salinity gradient has become a subject of growing interest as a source of renewable energy. One of the most widely used processes is reverse electrodialysis (RED), based on the use of ion exchange membranes and Faradaic electrodes. However, the use of real salt solutions containing mixtures of divalent and monovalent ions in the RED process results in a significant loss of recovered power, compared with salt solutions containing only monovalent ions. From an original point of view, in this work we study and explain the influence of divalent ions and complex solutions in reverse electrodialysis devices equipped with capacitive electrodes with a single membrane (CREDSM). We show that CREDSM mitigates the impact of divalent ions. From a quantitative point of view, the power recovered in a Faradaic cell drops by more than 75 % when the solutions contain 50 % molar fraction of divalent ions and by 33 % when the solutions contain 10 % molar fraction of divalent ions. For similar low-cost membranes with fairly low selectivity, recovered power drops by only 34 % when solutions contain 60 % moles of divalent ions in CREDSM. We show that only the membrane potential, which makes up half of the cell's open circuit potential, is affected. The potential of capacitive electrodes which counts for half of the potential cell does not decrease in the presence of divalents. For the same membrane under the same conditions, we estimate a loss of 62 % in a RED device Furthermore, the membrane is not poisoned by divalent ions because we periodically change the electrical current direction, by means of switching the feed waters. CREDSM devices do not show any variation in membrane resistance or membrane selectivity. The techno-economic analysis suggests further valorization of salinity gradients in industrial operations. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) lamellar membranes, featuring organized nanochannels, tunable interlayer spacing, and modifiable chemical properties, are emerging as promising candidates for both theoretical research and practical applications. Rational design and regulation of the physical/chemical properties of the nanofluidic channels as well as manipulation of external factors are crucial to achieve desirable performance for the applications related to mass transport. Focusing on the recent advances in ion and water transport within 2D nanofluidic channels, this work gives a brief overview of the fabrication of 2D lamellar membranes based on the strategy of exfoliation and reconstruction. Then the transport phenomena within 2D nanofluidic channels along with the mechanisms and influential factors are highlighted. The representative applications of 2D lamellar membranes are also covered, especially in the areas of osmotic energy conversion, water purification and desalination, as well as single‐ion separation and extraction. It is concluded with a discussion of the current challenges and future perspectives in this potential field. [ABSTRACT FROM AUTHOR]

Salinity gradient energy (SGE), known as blue energy is harvested from mixing seawater with river water in a controlled way using ion exchange membranes (IEMs). Using 2D materials as IEMs improves the output power density from a few Wm−2 to a few thousands of Wm−2 over conventional membranes. In this review, we survey the efforts taken to employ the different 2D materials as nanoporous or lamellar membranes for SGE and provide a comprehensive analysis of the fundamental principles behind the SGE. Overall, this review is anticipated to explain how the 2D materials can make SGE a viable source of energy. [ABSTRACT FROM AUTHOR]

This study is focused on fractionation of insulin-like growth factor I (IGF-I) and transforming growth factor-β2 (TGF-β2) using a new electro-based membrane process calledelectrodialysis with filtration membranes (EDFM). Before EDFM, different pretreatments were tested, and four pH conditions (4.25, 3.85, 3.45, and 3.05) were used during EDFM. It was demonstrated that a 1:1 dilution of defatted colostrum with deionized water to decrease mineral content followed by the preconcentration of GFs by UF is necessary and allow for these compounds to migrate to the recovery compartment during EDFM. MS analyses confirmed the migration, in low quantity, of only α-lactalbumin (α-la) and β-lactoglobulin (β-lg) from serocolostrum to the recovery compartment during EDFM. Consequently, the ratio of GFs to total protein in recovery compartment compared to that of feed serocolostrum solution was 60× higher at pH value 3.05, the optimal pH favoring the migration of IGF-I and TGF-β2. Finally, these optimal conditions were tested on acid whey to also demonstrate the feasibility of the proposed process on one of the main by-products of the cheese industry; the ratio of GFs to total protein was 2.7× higher in recovery compartment than in feed acid whey solution, and only α-la migrated. The technology of GF enrichment for different dairy solutions by combining ultrafiltration and electrodialysis technologies was proposed for the first time. [ABSTRACT FROM AUTHOR]

The article discusses the future of inorganic contaminants in drinking water and the challenges that water utilities may face in the coming years. It highlights that while the number of regulated inorganic contaminants has remained relatively stable over the past 26 years, compliance with current regulations can be difficult for some water systems. The article also identifies three inorganic contaminants, hexavalent chromium, arsenic, and manganese, that are likely to pose new challenges in the future. It emphasizes the importance of preparing for the future by developing innovative treatment technologies and addressing issues such as climate change and changing consumer expectations. [Extracted from the article]

The growing interest in forward osmosis (FO) for water reclamation and desalination over the past two decades stems from its potential for lower energy consumption. Despite its promise, FO faces significant challenges, such as the lack of an appropriate draw solute, concentration polarization, membrane fouling, and reverse solute flux (RSF). Recent trends in research have focused on combining various technologies with FO to address these challenges. Notably, the integration of electrochemical technologies with FO offers new possibilities. This review covers FO combined with electrochemical cells (FO‐ECs), categorizing them based on their working principles and applications in improving FO. The review discusses different FO‐EC configurations, including (1) electrodialysis‐combined FO for RSF, (2) electro‐FO for water flux enhancement, and (3) electrochemical oxidation‐combined FO and FO with electro‐conductive membranes for self‐cleaning and fouling mitigation. Additionally, it covers (4) reusable electro‐responsive draw solutes, (5) electrochemical osmosis systems for metal removal and energy production, and (6) osmotic microbial fuel cells for energy recovery and other benefits. The review also assesses the practical applicability and potential for achieving carbon neutrality of the FO‐ECs. It concludes with a forward‐looking perspective, outlining future research directions to optimize and expand the use of electrochemical‐enhanced FO technologies. [ABSTRACT FROM AUTHOR]

In light of the escalating population growth within Indonesia's coastal regions, there is a corresponding surge in the demand for fresh water and sanitation facilities. Addressing this challenge, the deployment of membrane-based desalination technology emerges as a viable solution to augment the fresh water supply for coastal communities. This study delves into the application of titanium dioxide (TiO2) as a material in membrane-based desalination processes--namely, electrodialysis (ED) and reverse osmosis (RO)--synthesized through an integrated approach that encompasses technological, environmental, social, and economic perspectives. Specifically, this approach is tailored for implementation among the Bajau Tribe in Pasikuta Village, located in the Southeast Sulawesi Province of Indonesia. The methodology encompasses technological research and a systematic literature review, supplemented by membrane design, desalination technology analysis, and a bibliometric study based on Scopus data. The findings reveal that the development of a simplified desalination system, which combines the ED-RO techniques utilizing TiO2-modified membranes, exhibits promising potential for adoption in coastal communities. Moreover, this system is characterized by its minimal impact on the marine ecosystem, thereby facilitating its straightforward and cost-effective application through the integration of photovoltaic (PV) technology for harnessing renewable energy. Crucially, the success of this desalination technology's community-based application hinges on community engagement, educational initiatives, and enhancements in community income levels, thereby establishing a sustainable model for mitigating water scarcity and reducing environmental repercussions. [ABSTRACT FROM AUTHOR]

The growing demand for lithium-ion batteries (LIBs) has led to significant environmental and resource challenges, such as the toxicity of LIBs' waste, which pose severe environmental and health risks, and the criticality of some of their components. Efficient recycling processes are essential to mitigate these issues, promoting the recovery of valuable materials and reducing environmental pollution. This review explores the application of electrodialysis in the process of recycling LIBs to contribute to the principles of circular hydrometallurgy. The article is structured to provide a comprehensive understanding of the topic, starting with an overview of the environmental and resource challenges associated with manufacturing LIBs. Then the current recycling processes are presented, focusing on hydrometallurgical methods. The concept of circular hydrometallurgy is introduced, emphasizing sustainable resource recovery. The electrodialysis technique is described in this context, highlighting its integration into the process of recycling LIBs to separate and recover valuable metals. Finally, the article addresses the challenges and limitations of the electrodialysis technique, such as energy consumption and system optimization, and identifies areas for future research and development. Through this analysis, the review aimed to contribute to advancing the development of more sustainable and efficient LIB recycling technologies, ensuring a safer and more environmentally friendly approach to the management of batteries' lifecycle. [ABSTRACT FROM AUTHOR]

Reverse electrodialysis (RED) is one of the methods able to generate energy from the salinity gradient between sea- and river water. The technique is based on the diffusion of ions through membranes that specifically allow either cations or anions to pass through. This ion current is converted into an external electric current at electrodes via suitable redox reactions. Seawater contains mainly eight different ions and the description of transport phenomena in membranes in classical terms of isolated species is not sufficient because the different particles have different velocities—in the same direction or opposite—in the same membrane. More realistic is the Maxwell–Stefan (MS) theory that takes all interactions between the different particles in account; however, such a model is complex and validation is difficult. Therefore, a simplified system is used with solely NaCl in solution, using only 9 diffusivities in the calculation. These values are estimated from the literature and are applied to an MS model of the RED process. Using experimental data of NaCl and water transport as well as power density, these diffusivities are adapted in the MS model. Reliable values for the diffusivities were obtained for the following three interactions: H2O–Na+, H2O–Cl− and Na+–Cl−. [ABSTRACT FROM AUTHOR]

Copyright of Technology of Water Treatment is the property of Technology of Water Treatment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bioremediation is an ingenious and promising method pertinent for recuperating and removing toxic metals in polluted water and lands. Arsenic (As) contamination is a crucial matter worldwide as its supersaturation is gradually intensifying in our environment because of natural and anthropogenic exertion. Microorganisms have a pivotal role in the bioremediation of various arsenic species. Microorganisms can presumably decrease arsenic by employing genetic engineering. By introducing innovative catabolic pathways with the help of different computational tools or by engineering the prevailing metabolic pathways, the limitations likely to crop up in bioremediation can be suppressed. This review accentuates the significance of microbes for the bioremediation of arsenic, and along with that, it scrutinizes the disadvantages and incapability of native and engineered microbes for bioremediation. In addition, arsenic bioremediation employing genetically modified bacteria is more ecologically friendly. It has fewer health hazards than physiochemical-based methods such as coagulation or filtration sedimentation, electrodialysis or osmosis, chemical precipitations, and adsorptions. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Investigating the dissociation of acids in the presence of a limited number of water molecules is crucial for understanding various elementary chemical processes. In our study, focusing on HCl(H2O)n clusters (where HCl is hydrogen chloride and H2O is water) formed in a cold and isolated jet expansion, we used the nuclear quadrupole coupling tensor obtained through rotational spectroscopy to decipher the nature of the hydrogen-chlorine (H-Cl) chemical bond in a microaqueous environment. For n = 1 to 4, the H-Cl bond is covalent. At n = 5 and 7, the contact ion pair of H3O+Cl− is spontaneously formed within the hydrogen bond networks of book and cube acid-water clusters, respectively. [ABSTRACT FROM AUTHOR]

The present investigation focuses on the design and construction of microbial fuel cells (MFCs) using cylindrical composite membranes in the vertical position, in order to treat domestic wastewater and generate electricity. The composite membranes were prepared with natural clay and activated carbon modified with chlorosulfonic acid using a physical mixture of 85 % clay and 15% modified carbon, and they received a heat treatment at 1000 °C to improve their mechanical resistance. Also, the physicochemical characterization of the composite membranes and their precursors was carried out to determine their morphology, functionalities, and chemical composition. In addition, ion transport tests across membranes were performed to evaluate their ion exchange properties. The components of the MFCs include a polypropylene vessel as the anode chamber, a graphite filter as the anode collector, a stainless-steel mesh as the cathode collector, and a cylindrical membrane as the ion exchange material. Different configurations were tested based on the cathode-anode size proportion (1:1, 1:2, and 2:1). The MFCs were operated at room temperature using wastewater from a municipal treatment plant with sodium acetate as a substrate. The stability and durability of the MFCs were evaluated by monitoring the voltage and power density over time. The composition of the wastewater was analyzed before and after each operation cycle. In general, composite membranes of clay and bituminous carbon modified with chlorosulfonic acid showed favorable characteristics for MFCs applications, such as better ion transport and conductivity. Cells using these membranes with a 2 cm electrode spacing and a cathode: anode size proportion of 1:2 demonstrated the best performance in terms of electricity generation and wastewater treatment. These MFCs achieved a power density of 24.76 mW/m3 and successfully powered an LED and digital clock as prototypes and reduced the overall Chemical Oxygen Demand (COD) by 77.96 %. [Display omitted] • Composite membranes of clay-carbon in cylindrical configuration were studied in MFC. • Membranes demonstrated enhanced ion transport and conductivity in MFC. • MFC were optimized using 1:2 cathode:anode proportion with 2 cm electrode spacing. • Power density of 24.76 mW/m3 and a 77.96 % reduction in COD was observed in MFC. [ABSTRACT FROM AUTHOR]

A forward‐bias bipolar membrane (BPM) provides an alkaline cathode condition, which can be beneficial to some electrochemical reactions, such as the CO2 reduction reaction (CO2RR), but the water association (WA) in forward‐bias BPM is not well understood at all. In this study, BPMs are designed with different interfacial polymeric catalysts to investigate the WA reaction under forward‐bias for electrochemical applications. An enhanced current density is observed with added polymeric catalysts (−OH, −O−, −N−, and graphene oxide) compared to the blank control. Temperature‐dependent measurements indicated that the WA in BPM is not kinetically controlled. The in‐plane and through‐plane ions diffusion is investigated, which showed that the WA in BPM is limited mostly by the transport of OH− and, to a lesser degree, H+ at the interface. Molecular dynamic studies presented that the migration rate of OH− at the interface is approximately one order of magnitude lower than that of H+, indicating that the WA is mainly governed by the transport of OH−. Finally, a forward‐bias CO2RR electrolyzer is demonstrated with an Faradaic effeiciency CO (FECO) of 92.2 ± 2.7%. This work provides important fundamental insights into the WA reaction that would enable the use of forward‐bias BPM electrolyzers in future electrochemical applications. [ABSTRACT FROM AUTHOR]