Membrane Electrodialysis Process Research Articles

Desalination of mother liquor generated from the precipitation of lithium carbonate during the recycling of retired lithium ion battery

Generally, hydrometallurgy process is adopted in factory to recover valuable metal from anode materials in lithium ion battery. The mother liquor generated from the precipitation of lithium carbonate in this process is often managed by evaporative crystallization process which is high energy-consuming and expensive. The methodology employed in this research involves pretreatment and bipolar membrane electrodialysis to partition salts within the mother liquor into acids and bases, thereby achieving cost savings. The findings reveal that a significant 76.5 % reduction in COD is achievable through the application of potassium permanganate and activated carbon in the treatment of the mother liquor. Subsequently, the treated mother liquor can be transfer to electrodialysis process for further treatment. During this process, desalination of the mother liquor occurs, leading to the decomposition of sodium sulfate into sulfuric acid and sodium hydroxide. Analysis of the experimental data reveals that optimizing the initial concentrations of sulfuric acid and sodium hydroxide within the acid and alkali collection chambers, along with the application of elevated electric current density and maintaining a high pH value of the mother liquor, yields improvements in current efficiency and concomitant reductions in energy consumption. Under optimal conditions, the current efficiency of acid and alkali preparation is 52.53 % and 62.12 % respectively, along with energy consumption of acid and alkali preparation is 8.68kWh/kg and 8.99kWh/kg respectively. The pretreatment and bipolar membrane electrodialysis process is low-energy consumption and inexpensive, facilitating a reduction in processing expenses to $6.659 per ton of mother liquor.

Optimizing Operational Parameters for Lithium Hydroxide Production via Bipolar Membrane Electrodialysis

Traditional lithium hydroxide production techniques, like lithium sulfate and lithium carbonate causticizing methods, suffer from drawbacks including high specific energy consumption, time-consuming processes, and low recovery rates. The conversion of lithium chloride to lithium hydroxide using bipolar membrane electrodialysis is straightforward; however, the influence of operational parameters on bipolar membrane electrodialysis performance have not been investigated. Herein, the impact of the current density (20 mA/cm2~80 mA/cm2), feed concentration (0.5 M~2.5 M), initial feed pH (2.5, 3.5 and 4.5), and the volume ratio of the feed and base solution (1:1, 2:1 and 3:1) on the current efficiency and specific energy consumption in the bipolar membrane electrodialysis was systematically investigated. The bipolar membrane electrodialysis process showed promising results under optimal conditions with a current density of 50 mA/cm2 and an initial lithium chloride concentration of 1.5 M. This process achieved a current efficiency of 75.86% with a specific energy consumption of 3.65 kwh/kg lithium hydroxide while also demonstrating a lithium hydroxide recovery rate exceeding 90% with a purity of about 95%. This work will provide valuable guidance for hands on implementation of bipolar membrane electrodialysis technology in the production of LiOH.

Heavy Metal Removal from Aqueous Solutions Using a Customized Bipolar Membrane Electrodialysis Process.

Lack of safe water availability and access to clean water cause a higher risk of infectious diseases and other diseases as well. Heavy metals (HMs) are inorganic pollutants that cause severe threats to humans, animals, and the environment. Therefore, an effective HM removal technology is urgently needed. In the present study, a customized bipolar membrane electrodialysis process was used to remove HMs from aqueous solutions. The impacts of the feed ionic strength, applied electrical potential, and the type and concentration of HMs (Cd2+, Co2+, Cr3+, Cu2+, and Ni2+) on the process performance were investigated. The results showed that feed solution pH changes occurred in four stages: it first decreased linearly before stabilizing in the acidic pH range, followed by an increase and stabilization in the basic range of the pH scale. HM speciation in the basic pH range revealed the presence of anionic HM species. The presence of HMs on anion exchange membranes confirmed the contribution of these membranes for HM removal in the base channels of the process. While no clear trend was seen in the ionic strength solution, the maximum HM removal was observed when 1.5 g/L NaCl was used. The initial HM concentration showed a linear increase in HMs removal of up to 30 mg/L. A similar trend was seen with an increase in the applied electrical potential of up to 15 V. In general, the amount of HMs removed increased in the following order: Cd2+ ˃ Ni2+ ˃ Co2+ ˃ Cu2+ ˃ Cr3+. Under some operational conditions, however, the removed amount of Cu2+, Co2+, and Ni2+ was similar. The mass balance and SEM-EDX results revealed that the removed HMs were sorbed onto the membranes. In conclusion, this process efficiently separates HMs from aqueous solutions. It showed the features of diluate pH adjustment, reduction in the overall stack electrical resistance, and contribution of anion exchange membranes in multivalent cation removal. The mechanisms involved in HMs removal were diffusion and migration from the bulk solution, followed by their sorption on both cation and anion exchange membranes.

Computational analysis of electric field effects on electrodialysis for enhanced desalination processes

This study elucidates the technologies employed in membranebased water purification processes. The theoretical underpinnings of semipermeable membrane functionalities are expounded upon through the lens of Onsager’s reciprocal relations in non-equilibrium thermodynamics, delineating the fluxes and the driving forces that instigate them. Utilising a simplified Onsager matrix tailored for the ion-exchange membrane electrodialysis process, computational fluid dynamics (CFD) simulations were conducted. The computations presented herein depict the intricacies of both dialysis and electrodialysis in saline water solutions.

Mechanistic investigation of intensified separation of molybdenum(VI) and vanadium(V) using polymer inclusion membrane electrodialysis

The main challenge in separating molybdenum(VI) and vanadium(V) which have similar properties results in great difficulties in the green recycling of hazardous spent catalysts. Here, selective facilitating transport and stripping are integrated into the polymer inclusion membrane electrodialysis process (PIMED) to separate Mo(VI) and V(V) to overcome the complicated co-extraction and stepwise-stripping in conventional solvent extraction. The influences of various parameters, the selective transport mechanism, and respective activation parameters were systematically investigated. Results revealed that the affinity of the Aliquat 36 as the carrier and PVDF-HFP as the base polymer of PIM towards Mo(VI) is stronger than that of V(V), while the strong interaction between Mo(VI) and carrier caused low migration through the membrane. By the combination of adjusting and controlling the electric density and strip acidity, the interaction was destroyed and the transport was facilitated. After optimization, stripping efficiencies of Mo(VI) and V (V) increased from 44.4% to 93.1% and reduced from 31.9% to 1.8%, respectively, while their separation coefficient increased 16.3 times to 333.4. The activation energy, enthalpy and entropy for the transport of Mo(VI) were determined to be 4.846 kJ mol−1, 6.745 kJ mol−1 and − 310.838 J mol−1 K−1, respectively. The present work demonstrates that the separation of similar metal ions could be improved by fine tuning the affinity and interaction between metal ions and the PIM, thus providing new insights into the recycling of similar metal ions from secondary resources.

Power-free bipolar membrane electrodialysis for acid-alkali production in river estuaries

Recent studies suggest that 2–2.6 TW blue energy can be harvested by mixing coastal seawater with freshwater world widely, but the extractable part was limited due to undesired development of conversion techniques. In this study, a novel power-free bipolar membrane electrodialysis process is proposed for the closed-loop utilization of salinity gradient energy and the salt resources in seawater. The system was evaluated using theoretical and experimental methods. Significance of the various membrane modules and operational conditions was evaluated. Based on fluid dynamics simulations and fluid online imaging technologies, a prototype electro-membrane reactor was fabricated to maximize the achievable energy and acid/base products. The acid production rate reached 6.9 mmol h−1 when feeding simulated seawater (30 g/L NaCl) and river water (1 g/L NaCl). The protocols provided in this work offer an effective route for developing advanced membrane processes for the harvesting of salinity gradient energy and acid-alkali production.

Modeling and Validation of a LiOH Production Process by Bipolar Membrane Electrodialysis from Concentrated LiCl.

Electromembrane processes for LiOH production from lithium brines obtained from solar evaporation ponds in production processes of the Salar de Atacama are considered. In order to analyze high concentrations' effect on ion exchange membranes, the use of concentrated LiCl aqueous solutions in a bipolar membrane electrodialysis process to produce LiOH solutions higher than 3.0% by mass is initially investigated. For this purpose, a mathematical model based on the Nernst-Planck equation is developed and validated, and a parametric study is simulated considering as input variables electrolyte concentrations, applied current density, stack design, process design and membrane characteristics. As a novelty, this mathematical model allows estimating LiOH production in a wide concentration range of LiCl, HCl and LiOH solutions and its effect on the process, providing data on final LiOH solution purity, current efficiency, specific electricity consumption and membrane performance. Among the main results, a concentration of 4.0% to 4.5% by LiOH mass is achieved, with a solution purity higher than 95% by mass and specific electrical energy consumption close to 4.0 kWh/kg. The work performed provides key information on process sensitivity to operating conditions and process design characteristics. These results serve as a guide in the application of this technology to lithium hydroxide production.

Factors Influencing the Formation of Salicylic Acid by Bipolar Membranes Electrodialysis.

Salicylic acid is an intermediate product in the synthesis of dyes, medications and aspirin. An electrodialysis module has been constructed with commercial cationic, anionic and bipolar membranes for the conversion of sodium salicylate into salicylic acid. The effect of operating conditions such as applied electric potential, salt concentration, initial acid concentration and volumetric flow on bipolar membrane electrodialysis (BMED) yields were investigated using Taguchi analysis. The results obtained in 210 min of work show an average concentration of salicylic acid of 0.0185 M, an average electric current efficiency of 85.3%, and a specific energy consumption of 2.24 kWh/kg of salicylic acid. It was concluded that the proposed bipolar membrane electrodialysis process is an efficient alternative to produce salicylic acid (SAH) from sodium salicylate (SANa) in an environmentally friendly manner. Furthermore, the production of sodium hydroxide was obtained as a by-product of the process carried out.

Recovery of Biologically Treated Textile Wastewater by Ozonation and Subsequent Bipolar Membrane Electrodialysis Process.

The Bipolar Membrane Electrodialysis process (BPMED) can produce valuable chemicals such as acid (HCl, H2SO4, etc.) and base (NaOH) from saline and brackish waters under the influence of an electrical field. In this study, BPMED was used to recover wastewater and salt in biologically treated textile wastewater (BTTWW). BPMED process, with and without pre-treatment (softening and ozonation), was evaluated under different operational conditions. Water quality parameters (color, remaining total organic carbon, hardness, etc.) in the acid, base and filtrated effluents of the BPMED process were evaluated for acid, base, and wastewater reuse purposes. Ozone oxidation decreased 90% of color and 37% of chemical oxygen demand (COD) in BTTWW. As a result, dye fouling on the anion exchange membrane of the BPMED process was reduced. Subsequently, over 90% desalination efficiency was achieved in a shorter period. Generated acid, base, and effluent wastewater of the BPMED process were found to be reusable in wet textile processes. Results indicated that pre-ozonation and subsequent BPMED membrane systems might be a promising solution in converging to a zero discharge approach in the textile industry.

Generation of acid–base by bipolar membrane electrodialysis process during desalination of pesticide containing wastewater

Generation of acid–base by bipolar membrane electrodialysis process during desalination of pesticide containing wastewater

Analysis of a Process for Producing Battery Grade Lithium Hydroxide by Membrane Electrodialysis.

A membrane electrodialysis process was tested for obtaining battery grade lithium hydroxide from lithium brines. Currently, in the conventional procedure, a brine with Li+ 4–6 wt% is fed to a process to form lithium carbonate and further used to produce lithium hydroxide. The disadvantages of this process are its high cost due to several stage requirement and the usage of lime, causing waste generation. The main objective of this work is to demonstrate the feasibility of obtaining battery grade lithium hydroxide monohydrate, avoiding production of lithium carbonate. A laboratory cell was constructed to study electrochemical kinetics and determine energetic parameters. The effects of current density, electrode material, electrolyte concentration, temperature and cationic membrane (Nafion 115 and Nafion 117) on cell performance were determined. Tests showed that a current density of 1200 A/m2 and temperatures between 75–85 °C allow reduced specific electricity consumption (SEC) (7.25 kWh/kg LiOH). A high purity product is obtained at temperatures below 75 °C, with a Nafion 117 membrane and low electrolyte concentration. Resulting key electrochemical data would enable a pilot-scale process implementation to obtain lithium compounds.

Graphene oxide modified porous P84 co-polyimide membranes for boron recovery by bipolar membrane electrodialysis process

Composite anion-exchange membranes with porous structures have been successfully prepared by incorporating quaternized graphene oxide (QGO) into P84 co-polyimide, and then undergoing the phase inversion, amination and quaternization processes. The membranes’ porous structures can be readily adjusted by the category of non-solvent during the phase inversion process. Large finger-like voids are present in the lower parts of the membrane cross sections by using water or 50% isopropanol aqueous solution, which facilitate the entrance of polyethylenimine chains into the membrane matrix, leading to higher degree of amination and quaternization. The incorporation of QGO does not influence the membrane morphology obviously, but can further enhance the ion exchange capacity (1.23–1.65 mmol/g) and decrease the membrane area resistance (1.6–1.9 Ω cm2).The QGO-P84 composite membranes are used in bipolar membrane electrodialysis (BMED) for the removal of boron from synthetic model solutions (Na2B4O7·10H2O, 1000 mg B/L). The finger-like pores decrease the steric resistance of boron transport, while the incorporation of QGO improves the membrane electro-chemical properties and thus the BMED performances. The separation efficiency is 76.6% after running 3 h under 30 V, the current efficiency is 94.9% and the energy consumption is 26.16 kW h/kg by using the optimal composite membrane. The BMED performances are better than those of commercial membrane CJMA-3 (separation efficiency of 51.6%, current efficiency of 81.2%, and energy consumption of 30.56 kWh/kg). Hence, the QGO-P84 composite membranes are effective for removal and recovery of boron from aqueous solution through BMED method.

Feed and Bleed Bipolar Membrane Electrodialysis Process

In this study, a bipolar membrane electrodialysis process (BPMED) is applied to regenerate nitric acid and ammonia by splitting ammonium nitrate. Firstly, we have proved the process feasibility in batch mode. Secondly, using the same operating conditions, we have proposed to extend the study to a continuous (feed and bleed) operating mode. Forecast calculations, derived from the balance material equations, and using the batch mode results, allowed the estimation of the continuous functioning parameters for both acid and salt. There is a good agreement between the performances of the two functioning modes. The acid and ammonia current efficiencies reached respectively 85 and 83 % in batch processing, and 83 and 80 % in continuous processing.

Application of response surface methodology to optimize the bipolar membrane electrodialysis process of preparing polyferric sulphate

Application of response surface methodology to optimize the bipolar membrane electrodialysis process of preparing polyferric sulphate

A novel process on preparation of ammonium metatungstate solution using bipolar membrane electrodialysis

ABSTRACTAn industrial (NH4)2WO4 solution was used to directly prepare ammonium metatungstate solution using bipolar membrane electrodialysis. The effects of current density, initial concentrations of NH4HCO3 and WO3 in feeds, temperature and pH of product solution on the process were investigated. A continuous running test was carried out under the optimum conditions and the results showed that the direct recovery of WO3 reached 99.97% with average current efficiency of 72.5% and power consumption of 0.877 kWh kg−1 WO3 using a feed solution containing 172.3 g L−1 WO3 and a base solution containing 1.5 mol L−1 NH4HCO3 with a current density of 700 A m−2 and a solution pH in salt compartment of 2.8 at 31°C for 600 min, indicating easy and stable operation of the bipolar membrane electrodialysis process.

Removal of chromium(VI) from aqueous solutions using a novel hybrid liquid membrane—electrodialysis process

Chromium(VI) is one of the most toxic metals, and the removal of this metal ion from effluents and waste waters is a problem of great significance. A novel hybrid process of electrodialysis and liquid membrane extraction is proposed for chromium(VI) removal from aqueous solutions. Transport through bulk liquid membranes was found to be effective for chromium(VI) anions removal from chloride acidic solutions during galvanostatic electrodialysis. Solutions of tri-n-octylamine with admixtures of di(2-ethylhexyl) phosphoric acid in 1,2-dichloroethane were used as the liquid membranes. Effects of current density, chromium(VI) and hydrochloric acid concentration in the feed solution, carrier and admixture concentration in the liquid membrane were studied, and optimal conditions were determined. It is demonstrated that a practically complete removal of chromium(VI) from the feed solution is achieved during 1.0–4.0h of electrodialysis. A maximal stripping degree of ∼90% is obtained under the optimal conditions. A possibility of effective single-stage removal of chromium(VI) into dilute solutions of hydrochloric, sulphuric, perchloric, phosphoric acids and water is demonstrated.

Separation of cobalt(II) from nickel(II) by a hybrid liquid membrane–electrodialysis process using anion exchange carriers

Cobalt and nickel are widely used in various branches of industry, are usually present together in industrial and waste solutions and have similar physical and chemical properties; therefore, the separation of the metals is an important practical problem. A hybrid process based on the bulk liquid membrane is proposed as a novel method for the selective separation of cobalt(II) from nickel(II). The process includes the transport of cobalt(II) anionic chlorocomplexes from 3 to 6mol/L HCl solutions through the liquid membranes containing tri-n-octylamine or trialkylbenzylammonium chloride in 1,2-dichloroethane during galvanostatic electrodialysis. A possibility of cobalt(II) transfer into dilute solutions of sulfuric, hydrochloric, nitric and perchloric acids accompanied by an effective separation from nickel(II) is demonstrated. Effects of the main electrodialysis parameters as well as of the composition of the liquid membranes, feed and strip aqueous solutions on the rate and selectivity of the cobalt(II) transport are studied, and optimum conditions are determined. It is shown that the rate of cobalt(II) transport increases with the increase in current density, hydrochloric acid and cobalt(II) initial concentration in the feed solution. The selectivity of the metal separation increases as the cobalt(II) or nickel(II) concentration in the initial mixture increases.

Recovery of mixed acid and base from wastewater with bipolar membrane electrodialysis—a case study

The current study simultaneously examined the treatability of wastewater by electrodialysis unit and recovery of ions removed as acidic/alkaline solutions. With a bipolar membrane electrodialysis process, the removed ions are stored separately in anolyte/catholyte solutions, and then turned into mixed acids and bases. After the treatment of the leachate using the BMED process, the molar concentration of H+ ions in the acidic solution and the OH− ions in the alkaline solution reached up to 0.095 and 0.048M (conditions: 1 L wastewater and 1 L anolyte/catholyte solutions), respectively. When the ratio of wastewater to initial volume of anolyte and catholyte was ¼ (1 L wastewater and 0.25 L anolyte or catholyte solutions) at the end of a 360-min treatment period, 3.8- (from 0.01995 to 0.07586M for [H+]) and 3.98- (from 0.02344 to 0.09333M for [OH−]) times more intense acid and base concentrations were determined, respectively. This demonstrates that the process can be considered as a cleaner technology for the treatability of wastewater by obtaining more concentrated acid and base as recovered material and fewer byproducts.

Evaluation of treatment and recovery of leachate by bipolar membrane electrodialysis process

Recovery studies are frequently carried out for electrodialysis (ED) processes. In this study, beyond examining the recovery of leachate components in an electrodialysis process, the use of that process to treat leachate-containing wastewater was simultaneously tested. Leachates were initially pre-treated (ultra filtration+cation exchange) to prevent clogging and harmful effect to the bipolar electrodialysis membranes. Optimum operating conditions were determined at the end of the experimental studies. Online observations during the electrodialysis process included the temperature-dependent reaction time, conductivity and changes of molar concentrations of H+ and OH− ions in both the anolyte and catholyte compartments in which removed ions were collected. The most important contaminants in leachates are organic substances and nitrogen compounds. For this reason, representations of organic substances, such as the chemical oxygen demand (COD), and nitrogenous compounds, such as total Kheldahl nitrogen (TKN) and ammonia-nitrogen (NH3-N), were also monitored in the electrodialysis effluent. Under the optimum operating conditions, removal of NH3-N, TKN and COD were determined in the effluent at 96.2%, 92.8% and 86.7%, respectively. The conductivity value was determined to be 1.97mS/cm at the end of the study.

Simulation of an ion exchange membrane electrodialysis process for continuous saline water desalination

A computer program is developed and a continuous ion exchange membrane process is simulated applying a constant voltage between electrodes. Inputting membrane characteristics, electrodialyzer specifi cations and electrodialysic conditions into the program, the performance of an electrodialyzer is predicted. Salt concentration in a desalted solution, current efficiency, desalting ratio, water recovery, energy consumption, current density distribution, current density non-uniformity coefficient, limiting current density are evaluated. Infl uence of cell voltage and salt concentration in a feeding solution on (1) the transport of ions (migration and diffusion) and solutions (electro-osmosis and hydro-osmosis) across a membrane pair, (2) ohmic and membrane voltage in a membrane pair and (3) electric resistance of membranes, desalting cells and concentrating cells in a stack are discussed at the inlets and outlets of desalting cells. Electro-osmosis, ohmic voltage and electric resistance of membranes are incre...