Boris Zaltzman to speak on ' Modeling ionic transport through charge-selective solid: Concentration polarization, overlimiting conductance and hydrodynamic instability. Theory and Experiment '
On October 21, 2019 Boris Zaltzman (Ben-Gurion University of the Negev) will speak on 'Modeling ionic transport through charge-selective solid: Concentration polarization, overlimiting conductance and hydrodynamic instability. Theory and Experiment.'
Interfacial micro-scale flows commonly arise upon a DC current passage from an electrolyte solution into a charge selective solid, such as an electrode, ion exchange granule or bed, membrane or gel, or array of nanochannels. Under conditions of extreme diffusion limitation (concentration polarization near the limiting current), these flows provide an efficient additional ionic transport mechanism in the diffusion layer at the solid/liquid interface. On the relevant short length scale these flows are driven primarily by the electric force acting upon the space charge of the interfacial electric double layer. The resulting slip-like flow is known as electro-osmosis. In our study we developed a theory of nonequilibrium electroosmotic slip relevant for extreme diffusion limitation conditions. Based on this theory, we studied a stability of quiescent conduction through a planar charge selective interface and predicted the onset of a symmetry breaking instability above a certain voltage threshold. The original motivation for our study was to search for explanation of the phenomenon of overlimiting conductance through charge-selective electrodialysis membranes. Our major finding, besides its contribution to understanding of a fundamental object of interface science: electric double layer under current and instability of quiescent conduction into a charge selective solid, is of potential importance for applications in electrochemistry and microfluidics (intensification of ionic mass transport near the electrodes), dynamics of microbatteries, high current electrodialysis and electrodionization.
Start time: 17:00
Address: 34 Tallinskaya Ulitsa, room 403 (HSE MIEM)