Effect of the global electroneutrality condition on electromigration Taylor-Aris dispersion in a microcapillary with finite Debye layer thickness.
J Chem Phys
; 160(19)2024 May 21.
Article
en En
| MEDLINE
| ID: mdl-38767258
ABSTRACT
In this work, the electromigration dispersion (EMD) due to the charged electrolytes in microchannels is considered without using the thin electrical double layer assumption. The electrokinetic flow and transport of ions are actuated within a rectangular micro-/nanochannel having a negative surface charge density under the influence of an external electric field. Due to the local variation of the conductivity and the nonvalidity of the electroneutrality condition, the local electric field varies as a function of the solute concentration, wall surface charge density, valency, and Debye layer length. The resulting electrokinetic flow due to the external electric field drives the fluid along with the charged species, where the Taylor-Aris dispersion separates the solutes into their different constituents. The local concentration dependence of the electric field leads to the formation of concentration profiles that are slightly asymmetric with respect to the standard Gaussian distribution. Including a finite Debye layer thickness has an effect on the advection of the species as well as the diffusion of the species. It is found that in cases where Debye layers are thicker, the species advects faster within the microchannel. This might give valuable insights into the nature of the EMD. Our model aims to predict the evolution of ionic concentration at all positions within the channel. A study of the higher-order statistics in skewness and kurtosis has also been conducted to obtain a better understanding of the idealized model consisting of a buffer solution.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Año:
2024
Tipo del documento:
Article
País de afiliación:
India