Interplay between adsorption and hydrodynamics in nanochannels: towards tunable membranes

Abstract

We study how adsorption of a near-critical binary mixture in a nanopore is modified by flow inside the pore. We identify three types of steady states upon variation of the pore Péclet number (${\mathrm{Pe}}_p$), which can be reversibly accessed by the application of an external pressure. Interestingly, for small ${\mathrm{Pe}}_p$ the pore acts as a weakly selective membrane which separates the mixture. For intermediate ${\mathrm{Pe}}_p$, the flow effectively shifts the adsorption in the pore thereby opening possibilities for enhanced and tunable solute transport through the pore. For large ${\mathrm{Pe}}_p$, the adsorption is progressively reduced inside the pore, accompanied by a long ranged dispersion of the mixture far from the pore.

5 pages, 4 figures

References in corpus (2)

• Soft matter in hard confinement: phase transition thermodynamics, structure, texture, diffusion and flow in nanoporous media - topical review
• Carbon membranes for efficient water-ethanol separation