The multi-functional system of electrochemical desalination, RhB degradation and Cr (VI) removal

Capacitive deionisation (CDI), as a novel electrochemical technology, has attracted a fast-growing research interest over the past years. However, the single function of salt removal limits further development of conventional CDI systems. Herein, we propose a multi-function CDI device, which can achieve the electrochemical desalination, degradation of organic pollutants and removal of heavy metal ions through the redox electrocatalytic deionisation technology. Sulphur-doped reduced graphene oxide (S@rGO) is utilised as the anode to catalyse the degradation of rhodamine B. The Pt-coated graphite paper is used as a cathode for the removal of dichromate ions by the electro-reduction process. The voltage plateau of S@rGO is reduced by similar to 0.35 V compared with the pure carbon cloth electrode, indicating the effectiveness of S@rGO as the catalyser. The salt feed is desalted to similar to 0.74 mS center dot cm(-1) level at a current density of 1 mA center dot cm(-2). The degradation efficiency of rhodamine B (RhB) and potassium dichromate are 99.1% and 55.3%, respectively. The effects of different current densities and cycling are also investigated. This work is significant for the multi-functional process of water treatment and the device design.Synopsis: The single function of salt removal limits the further development of the CDI system. A multi-function CDI device is proposed to achieve electrochemical desalination, organics degradation and dichromate ion removal.