Characterization of hollow fiber membranes by impedance spectroscopy

By Sebastian Bannwarth and Mariam Darestani and Hans Coster and Matthias Wessling
Published in Journal of Membrane Science NULL 2015

Abstract

Electrical impedance spectroscopy (EIS) is a simple and non-destructive method to characterize membranes and to monitor membrane processes. It can be used for instance to determine layer thicknesses or to observe fouling. Up to now it has only been applied to flat sheet membranes using a four-electrode measuring technique. Hollow fiber membranes are finding increasing application but monitoring the state of such membranes during operation is a difficult task. The aim of our work presented here is to adapt the electrical impedance spectroscopy method for use with hollow fiber membranes. For this purpose a new membrane module has been developed which allows electrical impedance measurements to be made on hollow fibers and capillary membranes using a 2-terminal method. For this one wire-shaped electrode is located inside the hollow fiber membrane and one ring-shaped electrode is located outside, around the membrane. In the experiments the applied \AC\ field used in the impedance measurements was in a radial direction; across the membrane from the lumen side to the shell side while the system was bathed by an electrolyte solution. A porous hydrophobic \PP\ membrane with a pore size of 0.2

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