Mass transfer of a neutral solute in polyelectrolyte grafted soft nanochannel with porous wall

Abstract

A soft nanochannel involves a soft interface that contains a polyelectrolyte layer (PEL) sandwiched between a rigid surface and a bulk electrolyte solution. Mass transfer of a neutral solute in a combined electroosmotic and pressure driven flow through a polyelectrolyte grafted charged nanochannel with porous wall is presented in this work. Assuming the PEL as fixed charged layer and PEL-electrolyte interface as a semi-penetrable membrane, analytical solutions were obtained for potential distributions (for small wall potential). Velocity profiles were also derived in the same domains, for both inside and outside the PEL. Convective-diffusive species balance equation was semi-analytically solved inside the PEL. Expression of length averaged Sherwood number was also obtained and effects of different parameters, namely, drag parameter (α), Debye parameter (κ ), and PEL thickness were studied in detail. The variation of permeate concentration and permeation flux across the porous wall was obtained.

Combined electroosmotic and pressure‐driven transport of neutral solutes across a rough, porous‐walled microtube

“…Several researchers have analyzed the mass transfer phenomenon in microtubes and soft nanochannels having smooth porous wall, under electroosmotic and pressure-driven flows, with both Newtonian and non-Newtonian fluids [26][27][28][29][30]. It may be noted that almost all the aforementioned studies mostly dealt with obtaining the expression of length-averaged Sherwood number and the consequent analysis of the effects of pertinent parameters like channel dimension, Debye parameter, suction velocity, PEL thickness (in the case of soft nanochannels), and so on.…”