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ICS-3 Group Seminar:

Reverse Osmosis for Separating Electrolyte Solutions

Emiliy K. Zholkovskiyy

Institute of Bio-Colloid Chemistry of National Academy of Sciences of Ukraine, Kiev, Ukraine

begin
27 Nov 2018 10:30
end
27 Nov 2018 11:30
venue
Seminarraum A1-3, Building 04.6, Entrance E1

Abstract:

Reverse Osmosis (RO) is a phenomenon and, simultaneously, respective separation technology which amounts to changing the composition of liquid solution by pressing the solution through a membrane having special properties.
The presentation will be concerned with major regularities inherent in the RO separation of electrolyte solutions.

By using the Irreversible Thermodynamic approach, we will define the membrane phenomenological parameters that are responsible for the RO separation of electrolytes. We will consider experimental methods of membrane characterization in terms of such coefficients and demonstrate how to compute the indicators of RO process when the coefficients are known functions of electrolyte concentrations in the equilibrium solution.

As well, we will discuss how to predict these functions from a variety of microscopic models describing membrane microscopic structure, namely, the models of (i) pores with charged walls; (ii) dielectric exclusion and (iii) solution-diffusion.

We will present the result of addressing both the purely membrane transport and the contribution of external convective- diffusion kinetics having an important negative impact on the indicators of RO separation process. Such an impact manifests itself through the phenomenon which is referred to as the Concentration Polarization (CP)- accumulation of solute in the feed solution region adjacent to the membrane surface. The CP results in a decrease of both the RO selectivity and productivity.

Additionally, the CP leads to fouling of membranes. A method of fighting with fouling will also be discussed in the presentation.

Contact

Prof. Dr. Gerhard Naegele
Phone: +49 2461 61-2504
Fax: +49 2461 61-2280
email: g.naegele@fz-juelich.de

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