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

Abstract

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.

Keywords:

• Composite carbon electrode
• TiO₂ nanoparticle
• Capacitive deionization
• Ion selectivity
• Electrical resistance

Acknowledgments

This work (Grant No. 000452390111) was supported by Business for Cooperative R&D between Industry, Academy, and Research Institute funded Korea Small and Medium Business Administration in 2011 and by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MEST) (No. 20110007754).

Notes

Presented at the International Conference on Desalination for the Environment, Clean Water and Energy, European Desalination Society, 23–26 April 2012, Barcelona, Spain