Dispersion of charged solute in charged micro- and nanochannel with reversible sorption

Abstract

We study dispersion of a charged solute in a charged micro- and nanochannel with reversible sorption and derive an analytical solution for mass fraction in the fluid, transport velocity and dispersion coefficient. Electrical double layer formed on the charged surface gives rise to a charge-dependent solute transport by modifying the transverse distribution of the solute. We discuss the effect of sorption and electrical double layer on solute transport and show that the coupling between sorption and electrical double layer gives rise to charge-dependent transport even for a thin double layer. However, in this case, it can be reduced to a simple non-charge-dependent case by introducing the intrinsic sorption equilibrium constant.

Keywords: Charged channel; Dispersion; Reversible sorption; Thin layer model.