The elucidation and quantification of resin bed conductivity during electrodeionization processes facilitate improved cell design and performance. The aim of this project was to identify the current pathways in two types of resin beds and the various ionic forms that are present during chromium removal using a porous-plug model. The first bed consisted of an IRA-67 resin (a gelatinous weak base anion resin) prepared with hydroxyl groups, which resulted in a specific conductivity of (k) over bar =4.8 x 10(-4) S cm(-1). When this anionic resin was conditioned with chloride groups, the value of (k) over bar was 2.98 x 10(-3) S cm(-1). Finally, for the mixed bed, which was comprised of IRA-67 and Dowex Mac-3 (a macroporous weak acid cation exchange resin) in a 1: 1 ratio, k was increased to 0.017 S cm(-1). Our results showed that mixed-bed resins provide conductivities that are 35-fold higher than those of resins with hydroxyl groups and six-fold higher than those of resins with chloride groups. (C) 2015 Published by Elsevier Ltd.