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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

Concentration profiles in the depletion boundary layer for a weak salt at potentials a) 37 Vth and b) 60 Vth.
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f7: Concentration profiles in the depletion boundary layer for a weak salt at potentials a) 37 Vth and b) 60 Vth.

Mentions: Figure 7 shows the concentration profiles of a weak salt in steady state at 37 Vth and 60 Vth. At the lower potential, pH = 7 and the cation and anion concentration match. After the onset of water splitting, the concentration of H+ has significantly increased and offsets the salt’s dissociation equilibrium towards the anion, by means of the electric field maintaining electroneutrality. A similar effect is described for weak acids as the barrier effect39. At x = 100 μm the anion concentration increases rapidly due to the positively charged membrane, which continues to 200 μm and has a fixed charge concentration of 1 M. It can be seen that at 37 Vth the salt is almost completely depleted and at 60 Vth an extended space charge region has formed. A supplementary video shows the concentration profiles of ions for the full range of voltages.


Ion transport through electrolyte/polyelectrolyte multi-layers.

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

Concentration profiles in the depletion boundary layer for a weak salt at potentials a) 37 Vth and b) 60 Vth.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f7: Concentration profiles in the depletion boundary layer for a weak salt at potentials a) 37 Vth and b) 60 Vth.
Mentions: Figure 7 shows the concentration profiles of a weak salt in steady state at 37 Vth and 60 Vth. At the lower potential, pH = 7 and the cation and anion concentration match. After the onset of water splitting, the concentration of H+ has significantly increased and offsets the salt’s dissociation equilibrium towards the anion, by means of the electric field maintaining electroneutrality. A similar effect is described for weak acids as the barrier effect39. At x = 100 μm the anion concentration increases rapidly due to the positively charged membrane, which continues to 200 μm and has a fixed charge concentration of 1 M. It can be seen that at 37 Vth the salt is almost completely depleted and at 60 Vth an extended space charge region has formed. A supplementary video shows the concentration profiles of ions for the full range of voltages.

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