The Role of Gravity in the Evolution of the Concentration Field in the Electrochemical Membrane Cell

Kornelia M Batko,Andrzej Ślęzak,Wioletta M Bajdur

doi:10.3390/e22060680

Kornelia M Batko, Andrzej Ślęzak + Show 1 more

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https://doi.org/10.3390/e22060680

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Abstract

The subject of the study was the osmotic volume transport of aqueous CuSO4 and/or ethanol solutions through a selective cellulose acetate membrane (Nephrophan). The effect of concentration of solution components, concentration polarization of solutions and configuration of the membrane system on the value of the volume osmotic flux ( in a single-membrane system in which the polymer membrane located in the horizontal plane was examined. The investigations were carried out under mechanical stirring conditions of the solutions and after it was turned off. Based on the obtained measurement results , the effects of concentration polarization, convection polarization, asymmetry and amplification of the volume osmotic flux and the thickness of the concentration boundary layers were calculated. Osmotic entropy production was also calculated for solution homogeneity and concentration polarization conditions. Using the thickness of the concentration boundary layers, critical values of the Rayleigh concentration number (), i.e., the switch, were estimated between two states: convective (with higher ) and non-convective (with lower ). The operation of this switch indicates the regulatory role of earthly gravity in relation to membrane transport.

Highlights

The membrane is a selective barrier separating the interior of the cell from its surroundings and plays a key role in the biological cell [1]
The authors presented the results of studies on the impact of the concentration of individual solution components and the configuration of the membrane system on the value of r ) in a single-membrane system, in which the polymer membrane was the volume osmotic flux
From the studies it results, that for conditions of concentration polarization and binary r is a linear and for ternary solutions a non-linear function of the solution concentration solutions Jvi r depends on the configuration of the membrane system

Summary

Introduction

The membrane is a selective barrier separating the interior of the cell from its surroundings and plays a key role in the biological cell [1]. Polymers constitute the majority of film-forming materials: polymers highly stable (e.g., polybenzimidazole, polyamide, polytriazole, cellulose acetate, cellulose triacetate, etc.) and biodegradable polymers (e.g., poly/lactic acid, cellulose, bacterial cellulose, chitozan, etc.) [3]. The membrane diffusion processes occurring spontaneously in real conditions are accompanied by the phenomenon of concentration polarization [6,7,8,9]. It consists in changing the concentration field or density of solutions in the areas on both sides of the membrane caused by the creation of concentration boundary layers.

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