Nernst-Planck transport theory for (reverse) electrodialysis: II. Effect of water transport through ion-exchange membranes

Tedesco, Michele; Hamelers, H.V.M.; Biesheuvel, P.M.

doi:10.1016/j.memsci.2017.02.031

Cited by 140 publications

(124 citation statements)

References 49 publications

Supporting

Mentioning

123

Contrasting

Order By: Relevance

“…[38] and for electrodialysis in ref. [39]. For the low desalination degrees as obtained in the present work, discretization in the y-direction into more nodes, will not significantly change the results of the calculations.…”

Section: Numerical Aspectsmentioning

confidence: 60%

Theory of Water Desalination with Intercalation Materials

et al. 2018

View full text Add to dashboard Cite

We present porous electrode theory for capacitive deionization (CDI) with electrodes containing nanoparticles that consist of a redox-active intercalation material. A geometry of a desalination cell is considered which consists of two porous electrodes, two flow channels and an anion-exchange membrane, and we use Nernst-Planck theory to describe ion transport in the aqueous phase in all these layers. A single-salt solution is considered, with unequal diffusion coefficients for anions and cations. Similar to previous models for CDI and electrodialysis, we solve the dynamic two-dimensional equations by assuming that flow of water, and thus the advection of ions, is zero in the electrode, and in the flow channel only occurs in the direction along the electrode and membrane. In all layers, diffusion and migration are only considered in the direction perpendicular to the flow of water. Electronic as well as ionic transport limitations within the nanoparticles are neglected, and instead the Frumkin isotherm (or regular solution model) is used to describe local chemical equilibrium of cations between the nanoparticles and the adjacent electrolyte, as a function of the electrode potential. Our model describes the dynamics of key parameters of the CDI process with intercalation electrodes, such as effluent salt concentration, the distribution of intercalated ions, cell voltage, and energy consumption.

show abstract

Section: Numerical Aspectsmentioning

confidence: 60%

Theory of Water Desalination with Intercalation Materials

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The modeling domain in refs. [3,18] could therefore be simplified to one membrane, half of a diluate channel, and half of a concentrate channel. Instead, in the present work, all of these symmetry-assumptions are dropped, and we include a possible difference in diffusion coefficients between anion and cation both in the membranes and in the spacer channel.…”

Section: Theory Of Ion Transport In Ion Exchange Membranesmentioning

confidence: 99%

“…(2) by using a different coefficient for diffusion than for electromigration, as we considered in ref. [3], where dispersion (mixing, leading to flatter concentration profiles) effectively led to…”

Section: Theory Of Ion Transport In Ion Exchange Membranesmentioning

confidence: 99%

Nernst-Planck transport theory for (reverse) electrodialysis: III. Optimal membrane thickness for enhanced process performance

Tedesco¹,

Hamelers²,

Biesheuvel³

2018

Journal of Membrane Science

Self Cite

View full text Add to dashboard Cite

The effect of the thickness of ion exchange membranes has been investigated for electrodialysis (ED) and reverse electrodialysis (RED), both experimentally and through theoretical modeling. By developing a two-dimensional model based on Nernst-Planck theory, we theoretically find that reducing the membrane thickness benefits process performance only until a certain value, below which performance drops. For ED, an optimum thickness can be identified in the range of 10-20 µm, while for RED the maximum power density is found for membranes that are three times as thick. Model calculations compare well with experimental data collected with a series of homogeneous membranes with the same chemical composition and a thickness in the range of 10-75 µm. Our results show that the classical picture that membranes should be as thin as possible (as long as they remain pinhole-free and structurally stable) is insufficient, and must be replaced by a more accurate theoretical framework.

show abstract

“…Tedesco et al [12,13] extend the Nernst-Planck equation to the membrane, and model the water transport through the membrane using the Maxwell-Stefan equation.…”

Section: Existing Electrodialysis Modelsmentioning

confidence: 99%

Entropy generation analysis of electrodialysis

Chehayeb

Lienhard

2017

Desalination

View full text Add to dashboard Cite

Electrodialysis (ED) is a desalination technology with many applications. In order to better understand how the energetic performance of this technology can be improved, the various losses in the system should be quantified and characterized. This can be done by looking at the entropy generation in ED systems. In this paper, we implement an ED model based on the Maxwell-Stefan transport model, which is the closest model to fundamental equations. We study the sources of entropy generation at different salinities, and locate areas where possible improvements need to be made under different operating conditions. In addition, we study the effect of the channel height, membrane thickness, and cell-pair voltage on the specific rate of entropy generation. We express the second-law efficiency of ED as the product of current and voltage utilization rates, and study its variation with current density. Further, we define the useful voltage that is used beneficially for separation. We derive the rate of entropy generation that is due to the passage of ions through a voltage drop, and we investigate whether voltage drops themselves can provide a good estimate of entropy generation.

show abstract

Nernst-Planck transport theory for (reverse) electrodialysis: II. Effect of water transport through ion-exchange membranes

Cited by 140 publications

References 49 publications

Theory of Water Desalination with Intercalation Materials

Theory of Water Desalination with Intercalation Materials

Nernst-Planck transport theory for (reverse) electrodialysis: III. Optimal membrane thickness for enhanced process performance

Entropy generation analysis of electrodialysis

Contact Info

Product

Resources

About