Ion-selective composite carbon electrode coated with TiO2 nanoparticles for the application of electrosorption process

Composite carbon electrodes with ion selectivity were fabricated using mixtures of sulfonated polystyrene and Titanium dioxide (TiO2) nanoparticles that were coated onto carbon electrodes. After composite carbon electrodes with various TiO2 contents were coated in the coating solution in the range of 0-20 wt%, the scanning electron microscopy, cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS) were performed. In addition, the desalination performance was evaluated through the use of a capacitive deionization (CDI) unit cell. The CV and EIS analyses of the composite carbon electrodes showed that the electrical resistances of the coating layers decreased significantly as the TiO2 content increased. In contrast, the ion selectivity decreased as the TiO2 content increased because of the pores formed among the particles. In this study, the optimal content of TiO2 in the composite carbon electrodes in terms of electrical resistance and ion selectivity was found to be approximately 10 wt%. In addition, the desalination experiments confirmed that the desalination efficiency of the composite carbon electrodes was improved by approximately 30% over that of unmodified carbon electrodes. The composite carbon electrodes fabricated in this study can be used effectively in the CDI process.