ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mass transfer examination in electrodialysis using limiting current measurements

Natália Káňavová, Anna Krejčí, Martina Benedeková, Marek Doležel, and Lubomír Machuča

MemBrain s.r.o., Pod Vinicí 87, 471 27 Stráž pod Ralskem, Czech Republic

E-mail: natalia.kanavova@membrain.cz

Abstract: The impact of electrodialysis module characteristics on mass transfer was examined using the limiting current method. The current-voltage curves of different electrodialysis modules were measured and limiting currents were determined using the derivative method. The mass transfer coefficients were calculated and the parameters of their dependence on linear flow velocity were estimated. From these the impact of spacer thickness, spacer net type, membrane type, and module geometry were evaluated. It was found that the impact of spacer thickness was almost negligible within the examined range, but a decrease in the mass transfer coefficient could be expected in the case of thicker spacers. By contrast, the spacer net type and type of membrane were found to be very important parameters able to significantly influence the mass transfer. By modifying the module geometry, the mass transfer coefficient could also be altered and, only in this case, the exponential parameter of the dependence was changing. The parameters thus determined may be used to calculate the limiting current in a wide range of operational conditions and may help predict the performance of different electrodialysis module types

Keywords: electrodialysis – ion exchange membrane – limiting current – mass transfer coefficient

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0062

Chemical Papers 69 (4) 553–559 (2015)