The Mathematical Institute, University of Oxford, Eprints Archive

Diffusion and permeation in binary solutions: Application to
protein ultrafiltration

Peppin, Stephen S. L. (2009) Diffusion and permeation in binary solutions: Application to
protein ultrafiltration.
Not specified . (Submitted)

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Abstract

During the ultrafiltration of colloidal solutions the particles can form a porous medium (filter cake) or a diffuse boundary layer (concentration polarization) above the semipermeable membrane depending on the magnitude of the filtration pressure. In order to provide a unified description of these phenomena the present work develops some connections between irreversible thermodynamics and poroelasticity. In particular, Fick’s and Darcy’s laws are shown to provide an equivalent description except in two limiting cases – infinite dilution and infinite rigidity of the solute. A new expression for the generalized Stokes-Einstein equation is also obtained, which incorporates the poroelastic Biot-Willis coefficient accounting for the compressibility of the solvent. The theory is utilized to predict the pressure and concentration profiles during the ultrafiltration of a protein solution. The model captures the formation of a diffuse polarization layer at low pressures and a nearly rigid filter cake at higher pressures, as well as intermediate stages. The predicted Darcy pressure profile across the polarization layer is in good quantitative agreement with experimental measurements.

Item Type:Article
Subjects:D - G > Fluid mechanics
Research Groups:Oxford Centre for Collaborative Applied Mathematics
ID Code:808
Deposited By:Dr M. Stoll
Deposited On:23 Sep 2009 08:31
Last Modified:23 Sep 2009 08:31

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    protein ultrafiltration. (deposited 23 Sep 2009 08:31)
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