Electro‐kinetically enhanced mass transport of charged macro‐solutes through a microchannel with porous walls

Abstract

Electrokinetics of the solute transport across the porous walls of micro channel is important from its practical application but less explored. Transport of the charged macro‐solutes across perm‐selective walls in a microchannel is investigated. The extended Nernst–Planck equation describes the charged macro‐solutes distribution in the mass transfer boundary layer over the porous wall. The transverse electromigration of the charged macro‐solute either augments or suppresses the concentration polarization and the permeation rate depending on the wall and solute surface potential (attractive or repelling). The wall potential is screened due to the electrical double layer interaction of the wall and charged solute. It is observed that the charged solute concentration over the channel wall enhances by two times in case of oppositely charged interactions (unlike solute and channel wall) compared to like charges. The findings of this study can facilitate understanding of electrokinetic based drug delivery and separation systems involving charged solutes.

Anode Boundary Layer Extraction Strategy for H+–OH– Separation in Undivided Electrolytic Cell: Modeling, Electrochemical Analysis, and Water Softening Application

“…In the electrolysis system, as the electro-mobility of H + is significantly higher than other ions, the electro-migration process of H + will be negligibly influenced by other ions (Table S2). Since the magnitude of the electrostatic force between ions is only from 10 –12 to 10 –10 N, its effect on H + can also be completely ignored. , The contribution of diffusion behavior to the value of J H was negligible as compared with electro-migration since the relative magnitude value of electro-migration to diffusion was as high as 368–746 at a current density ranging from 6 to 22 mA cm –2 according to eq . ,, In addition, based on eqs and , it can be calculated that the R e value was increased from 74 to 167 as the influent flow rate increased from 330 to 1000 mL min –1 (Figure b). The laminar flow state with low R e value suggests no convective mixing happened near the anode surface .…”