Laser interferometric investigation of solute transport through membrane-concentration boundary layer system.

Sławomir Wąsik,Kazimierz Dworecki,Arkadiusz Bryll,Marcin Drabik,Andrzej Ślęzak

doi:10.1007/s10867-015-9387-y

Abstract

We investigate diffusive transport in a membrane system with a horizontally mounted membrane under concentration polarization conditions performed by a laser interferometry method. The data obtained from two different theoretical models are compared to the experimental results of the substance flux. In the first model, the membrane is considered as infinitely thin, while in the second one as a wall of finite thickness. The theoretical calculations show sufficient correspondence with the experimental results. On the basis of interferometric measurements, the relative permeability coefficient (ζs) for the system, consisting of the membrane and concentration boundary layers, was also obtained. This coefficient reflects the concentration polarization of the membrane system. The obtained results indicate that the coefficient ζs of the membrane-concentration boundary layer system decreases in time and seems to be independent of the initial concentration of the solute.

Highlights

The concentration boundary layers (CBLs) created near membrane surfaces act as pseudomembranes in series with the physical membrane
Poland 2 Department of Biophysics, Częstochowa University of Technology, 36B Armia Krajowa Al., 42200 Częstochowa, Poland membrane system in a stationary state is approximately nine times higher than in a gravitationally stable configuration
To describe the concentration polarization of a system, we introduce the relative permeability coefficient for a system consisting of membrane and concentration boundary layers [1], called the diffusive Katchalsky factor [33, 34] and propose the model equation for this coefficient and its dependence on different parameters [2]

Summary

Introduction

The concentration boundary layers (CBLs) created near membrane surfaces act as pseudomembranes in series with the physical membrane. It should be stressed that an important result of our study in addition to determining the relative permeability coefficient for the membrane/layers system is to determine the transport parameters of the membrane, i.e., the selectivity coefficient (γ) for an infinitely thin membrane and the partition coefficient (k) of the substance in the membrane/solution interface for the membrane of the finite thickness. The knowledge of these parameter values allows for a better understanding of the structure and permeability of the membrane, in the study of biological membrane models [41, 42]

Theoretical description

Membrane system

Experimental setup

Results and discussion