Improved capacitive deionization performance by coupling TiO2 nanoparticles with carbon nanotubes

In this paper, TiO2 nanoparticles (NPs) were exploited with carbon nanotube (CNTs) to form a composite electrode (TiO2/CNTs) for capacitive deionization (CDI). The phase morphology, crystal and electronic structure were characterized by scanning electron microscopy, Transmittance electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The electrochemical behavior was carried out by cyclic voltammetry. Furthermore, the desalination performances of TiO2/CNTs composite electrode were investigated at different electrical voltages and ionic strengthen in a batch mode operation. The results demonstrated that the TiO2/CNTs electrode prepared from 1 wt% TiO2 NPs (TiO2/CNTs-1) exhibits the best results compared to other electrodes having 2 and 5 wt% TiO2 NPs. Remarkably, the best electrode showed high specific capacitance (122 F/g) at 1 mV/s in 1 M KCl solutions and excellent electrosorptive capacity (4 mg/g) predicted from Langmuir isotherm which is nearly twice higher than that of pristine CNTs electrode. Moreover, the electrosorption follows the pseudo first adsorption kinetics and the proposed electrode shows interesting recyclability and easy full regeneration.