A Method for Removing Ions from Aqueous Solution by Electric Double Layer Formed Using Active Carbon

Abstract

A batch method to remove ions rapidly from aqueous solution by applying a high voltage was investigated. In this method, activated carbon cloth, which forms an electric double layer in aqueous solution, was employed as the ion-absorbing electrodes. Two electrodes were set in parallel with a wide inter-electrode spacing in an ion-containing aqueous solution. The current density was set from 0.3 to 13 mA/cm² and a voltage of 1 to 60 V was applied between the electrodes.
As a result, a high voltage could be easily applied using the IR drop in the aqueous solution, so ions were removed from the aqueous solution at a high rate. The activated carbon surface was used effectively because ions stay inside the electrodes until the deionization process ends in the batch method.
This method is promising as a new ion removal method that is simple to operate and easily self-recycling.