Deionization Shock Driven by Electroconvection in a Circular Channel
arXiv:1901.10648 · doi:10.1103/PhysRevFluids.4.113701
Abstract
In a circular channel passing over-limiting current (faster than diffusion), transient vortices of bulk electroconvection are observed in salt-depleted region within the horizontal plane. The spatiotemporal evolution of the salt concentration is directly visualized, revealing the propagation of a deionization shock wave driven by bulk electroconvection up to millimeter scales. This novel mechanism leads to quantitatively similar dynamics as for deionization shocks in charged porous media, which are driven instead by surface conduction and electro-osmotic flow at micron to nanometer scales. The remarkable generality of deionization shocks under over-limiting current could be used to manipulate ion transport in complex geometries for desalination and water treatment.
arXiv comment5 pages, 4 figures
References in corpus (11)
- Overlimiting current in a microchannel
- Equilibrium Electro-osmotic Instability
- Current-induced membrane discharge
- Desalination shocks in microstructures
- Experimental Verification of Overlimiting Current by Surface Conduction and Electro-osmotic Flow in Microchannels
- Over-limiting Current and Control of Dendritic Growth by Surface Conduction in Nanopores
- Dynamics of microvortices induced by ion concentration polarization
- On the coupling between buoyancy forces and electroconvective instability near ion-selective surfaces
- Induced Charge Capacitive Deionization: The electrokinetic response of a porous particle to an external electric field
- Interfacial dynamics in transport-limited dissolution
- Theory of voltammetry in charged porous media