Kinetic modeling and selectivity of anion exchange in Donnan dialysis

Beck, Adam; Ernst, Mathias

doi:10.1016/j.memsci.2014.12.037

Cited by 17 publications

(6 citation statements)

References 20 publications

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“…This anomaly can be explained by the difference in the ion-exchange membranes. Hydrogen ions pass through the anion-exchange membrane relatively easily compared with the resistance to the flow of hydroxide ions offered by the cation-exchange membrane [35]. This phenomenon is also one of the reasons for the loss in the current efficiency, as depicted in Figure 3d.…”

Section: Effect Of Current Densitymentioning

confidence: 99%

Recycling Lithium from Waste Lithium Bromide to Produce Lithium Hydroxide

et al. 2021

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Lithium resources face risks of shortages owing to the rapid development of the lithium industry. This makes the efficient production and recycling of lithium an issue that should be addressed immediately. Lithium bromide is widely used as a water-absorbent material, a humidity regulator, and an absorption refrigerant in the industry. However, there are few studies on the recovery of lithium from lithium bromide after disposal. In this paper, a bipolar membrane electrodialysis (BMED) process is proposed to convert waste lithium bromide into lithium hydroxide, with the generation of valuable hydrobromic acid as a by-product. The effects of the current density, the feed salt concentration, and the initial salt chamber volume on the performance of the BMED process were studied. When the reaction conditions were optimized, it was concluded that an initial salt chamber volume of 200 mL and a salt concentration of 0.3 mol/L provided the maximum benefit. A high current density leads to high energy consumption but with high current efficiency; therefore, the optimum current density was identified as 30 mA/cm2. Under the optimized conditions, the total economic cost of the BMED process was calculated as 2.243 USD·kg−1LiOH. As well as solving the problem of recycling waste lithium bromide, the process also represents a novel production methodology for lithium hydroxide. Given the prices of lithium hydroxide and hydrobromic acid, the process is both environmentally friendly and economical.

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Section: Effect Of Current Densitymentioning

confidence: 99%

Recycling Lithium from Waste Lithium Bromide to Produce Lithium Hydroxide

et al. 2021

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“…To maintain the solution electroneutrality, it was favorable for the migration of H + ions through the MSAEM under the influence of the chemical potential. Secondly, the selectivity of the anion-exchange membrane against the protonic co-ions was lower than the selectivity of the cation-exchange membrane against the anionic co-ions [27,32,33]. Due to the small ionic size and low valence of the proton, most commercial anion-exchange membranes have poor blockage performance against H + ions.…”

Section: Effect Of Current Densitymentioning

confidence: 99%

“…Due to the existence of the MSAEM, the Cl − ions could be further transported across the MSAEM into the acid I compartment and combined with the protons generated by the bipolar membrane, while the SO 4 2− ions were retarded by the MSAEM and would be kept in the acid II compartment. Since most anion-exchange membranes have poor blockage against protons [25][26][27], to maintain the electro-neutrality in the acid II compartment, it was easy for the protons to migrate though the MSAEM into the acid II compartment in the presence of a direct current field. Meanwhile, the Na + ions would be transported through the CEM into the base compartment and combined with OH − ions generated by the bipolar membrane.…”

Section: Operating Principle Of the Sbmedmentioning

confidence: 99%

In-Situ Combination of Bipolar Membrane Electrodialysis with Monovalent Selective Anion-Exchange Membrane for the Valorization of Mixed Salts into Relatively High-Purity Monoprotic and Diprotic Acids

Yan

Li²,

Zhou

et al. 2020

Membranes

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The crystalized mixed salts from the zero liquid discharge process are a hazardous threat to the environment. In this study, we developed a novel electrodialysis (SBMED) method by assembling the monovalent selective anion-exchange membrane (MSAEM) into the bipolar membrane electrodialysis (BMED) stack. By taking the advantages of water splitting in the bipolar membrane and high perm-selectivity of MSAEM for the Cl− ions against the SO42− ions, this combination allows the concurrent separation of Cl−/SO42− and conversion of mixed salts into relatively high-purity monoprotic and diprotic acids. The current density has a significant impact on the acid purity. Both the monoprotic and diprotic acid purities were higher than 80% at a low current density of 10 mA/cm2. The purities of the monoprotic acids decreased with an increase in the current density, indicating that the perm-selectivity of MSAEM decreases with increasing current density. An increase in the ratio of monovalent to divalent anions in the feed was beneficial to increase the purity of monoprotic acids. High-purity monoprotic acids in the range of 93.9–96.1% were obtained using this novel SBMED stack for treating simulated seawater. Therefore, it is feasible for SBMED to valorize the mixed salts into relatively high-purity monoprotic and diprotic acids in one step.

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“…Additionally, co-ions are not completely rejected by ion-exchange membranes (Beck and Ernst, 2015;Pessoa-Lopes et al, 2016). The Na + concentration gradient set up by the high [NaCl] in the RS results in Na + permeation from RS to FS, i.e., co-ion (cation) leakage.…”

Section: Electro-osmosis Due To H X Pomentioning

confidence: 99%

“…Additionally, Na + leakage is more exacerbated with conditions of higher initial RS [NaCl] due to increased Na + concentration gradients. (Beck and Ernst, 2015;Pessoa-Lopes et al, 2016) Consequently, the undesired co-permeation of Cl − is elevated. In principle, [Cl − ] FS,f (gray columns in Fig.…”

Section: Electro-osmosis Due To H X Pomentioning

confidence: 99%