A control system for operating and investigating reactors: The demonstration of parasitic reactions in the water desalination by capacitive de-ionization

We have developed a system for operating, measuring and characterizing reactors for water desalination by a capacitive de-ionization (CDI) method. The system monitors and controls the flow of water through the reactor, which consists of activated carbon electrodes. In-house software controls the reactor, collects and processes the relevant data. In this paper, our system is described in detail along with its advantages for the modular study of various reactors. We describe herein a study of a symmetrical CDI cell based on activated carbon electrodes. Parasitic surface reactions of the carbon, electrodes were observed in spite of the fact that the desalination is occurring within the electrochemical window of water (1.23. V). Over time, these reactions oxidize the carbon's surface area, resulting in diminished conductivity, which detrimentally affect the desalination process. In the present paper, we discuss the effects of the experimental conditions on the surface reactions of the carbon electrodes in CDI cells.