Titanium Dioxide/Activated Carbon Electrode with Polyurethane Binder for the Removal of Indium Ions via Capacitive Deionization

• Main Authors: Clive H. Yen, Shun-Hsing Chuang, Ren-Yi Huang, Po-I Liu, Min-Chao Chang, Ren-Yang Horng
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Processes
• Subjects: capacitive deionization; indium removal; microwave-assisted ionothermal synthesis; polyurethane; adsorption
• Online Access: https://www.mdpi.com/2227-9717/9/8/1427

The process of removing indium ions from aqueous solutions by applying capacitive deionization (CDI) is reported in this manuscript. First, a modified carbon material was prepared by incorporating titanium dioxide (TiO₂) into activated carbon (AC). A microwave-assisted ionothermal synthesis (MAIS) method was used to produce evenly distributed nanostructured anatase TiO₂ on the surface of AC. A polyurethane (PU) elastomer was then synthesized as the binder material instead of using conventional polyvinylidene fluoride (PVDF). By combining the aforementioned materials, a MAIS TiO₂/AC-PU electrode was synthesized and applied to CDI tests. Scanning electron microscopy (SEM) was used to characterize the size and dispersion of the composites. For electrochemical properties, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to analyze the synthesized electrode. The performance of the prepared electrode during the CDI process was tested in different concentrations of indium solutions. It was discovered that the indium removal efficiency can be as high as 84% in 1 and 5 ppm of indium solutions.