Tio2 and carbon nanotubes composites modify capacitive deionization anodes to improve the dechlorination efficiency in desulfurization wastewater.

Abstract

A new capacitive deionization (CDI) technology was used to remove Cl- from desulfurization wastewater. TiO2 and carbon nanotubes (CNTs) were combined with N-methyl pyrrolidone (NMP) to form composites by a solvothermal method in which it is coated onto the CDI anode to improve dechlorination efficiency (DE). The morphology, surface area, wettability, crystal structure and chemical composition of the TiO2/CNTs were characterized. They showed good hydrophilicity (contact angle: 85.9°), high specific surface area (96.68 m²/g) and high specific capacitance (87.6 F/g). The experimental results illustrated that the best DE was achieved by the composites (60%T/C) under 1.2 V with the maximum electrosorption capacity toward 6.5 mg/g, and the TiO2/CNTs composites had excellent stability. Adsorption kinetics analysis was explored and analyzed. Furthermore, TiO2/CNTs composites exhibited excellent DE in actual desulfurization wastewater. The catalysis and adsorption mechanisms of the TiO2/CNTs anode were discussed in detail. This study provides a new direction for the application of TiO2/CNTs composites as adsorption materials of CDI in the Cl- of desulfurization wastewater.