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Ion transport through electrolyte/polyelectrolyte multi-layers.

Femmer R, Mani A, Wessling M - Sci Rep (2015)

Bottom Line: Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems.EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers.We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

View Article: PubMed Central - PubMed

Affiliation: AVT Chemical Process Engineering, RWTH Aachen University, Turmstr. 46, 52064 Aachen, Germany.

ABSTRACT
Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems. We report a new direct numerical simulation model coined EnPEn: it allows to solve a set of first principle equations to predict for multiple ions their concentration and electrical potential profiles in electro-chemically complex architectures of n layered electrolytes E and n polyelectrolytes PE. EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers. We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

No MeSH data available.


Related in: MedlinePlus

Graphical representation of the architectures described with the new (EnPEn) model of n electrolytes En and n polyelectrolytes PEn and a number of occuring phenomena.Shown are the (a) principles of electrodialysis for desalination, (b) concentration profiles for weak electrolytes in the concentration polarization layer, (c) the principle of a bipolar membranes for acid and base production and (d) selectivity in layer-by-layer modified membranes.
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f1: Graphical representation of the architectures described with the new (EnPEn) model of n electrolytes En and n polyelectrolytes PEn and a number of occuring phenomena.Shown are the (a) principles of electrodialysis for desalination, (b) concentration profiles for weak electrolytes in the concentration polarization layer, (c) the principle of a bipolar membranes for acid and base production and (d) selectivity in layer-by-layer modified membranes.

Mentions: Experimental ion transport studies have been reported extensively over more than 30 years - mostly for strong electrolytes. The studies can be categorized in (a) fundamental mass transport studies or (b) application studies, the latter being excluded from this background information. Fundamental mass transport studies are mostly performed by measuring classical current voltage relationships. The shape of such IV-curves is frequently affected by concentration polarization phenomenon (CP) which relates to the development of concentration gradients in electrolyte solutions next to ion-selective membranes due to slow diffusion in the boundary layer as compared to more rapid transport in the membrane. Typical concentration profiles are shown in Fig. 1a. Their micrometer scale shape can be resolved experimentally using precise positioning of microelectrodes at various distances from the membrane. Ion distribution at the interface as shown in Fig. 1b however can be only accessed through simulations. Such phenomena happen equally likely at electrodes7. The mathematical treatment of the macroscopic diffusion phenomena governing concentration polarization is hence very similar in both systems. However, a detailed description of the interfacial phenomena is much more complex.


Ion transport through electrolyte/polyelectrolyte multi-layers.

Femmer R, Mani A, Wessling M - Sci Rep (2015)

Graphical representation of the architectures described with the new (EnPEn) model of n electrolytes En and n polyelectrolytes PEn and a number of occuring phenomena.Shown are the (a) principles of electrodialysis for desalination, (b) concentration profiles for weak electrolytes in the concentration polarization layer, (c) the principle of a bipolar membranes for acid and base production and (d) selectivity in layer-by-layer modified membranes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481379&req=5

f1: Graphical representation of the architectures described with the new (EnPEn) model of n electrolytes En and n polyelectrolytes PEn and a number of occuring phenomena.Shown are the (a) principles of electrodialysis for desalination, (b) concentration profiles for weak electrolytes in the concentration polarization layer, (c) the principle of a bipolar membranes for acid and base production and (d) selectivity in layer-by-layer modified membranes.
Mentions: Experimental ion transport studies have been reported extensively over more than 30 years - mostly for strong electrolytes. The studies can be categorized in (a) fundamental mass transport studies or (b) application studies, the latter being excluded from this background information. Fundamental mass transport studies are mostly performed by measuring classical current voltage relationships. The shape of such IV-curves is frequently affected by concentration polarization phenomenon (CP) which relates to the development of concentration gradients in electrolyte solutions next to ion-selective membranes due to slow diffusion in the boundary layer as compared to more rapid transport in the membrane. Typical concentration profiles are shown in Fig. 1a. Their micrometer scale shape can be resolved experimentally using precise positioning of microelectrodes at various distances from the membrane. Ion distribution at the interface as shown in Fig. 1b however can be only accessed through simulations. Such phenomena happen equally likely at electrodes7. The mathematical treatment of the macroscopic diffusion phenomena governing concentration polarization is hence very similar in both systems. However, a detailed description of the interfacial phenomena is much more complex.

Bottom Line: Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems.EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers.We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

View Article: PubMed Central - PubMed

Affiliation: AVT Chemical Process Engineering, RWTH Aachen University, Turmstr. 46, 52064 Aachen, Germany.

ABSTRACT
Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems. We report a new direct numerical simulation model coined EnPEn: it allows to solve a set of first principle equations to predict for multiple ions their concentration and electrical potential profiles in electro-chemically complex architectures of n layered electrolytes E and n polyelectrolytes PE. EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers. We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

No MeSH data available.


Related in: MedlinePlus