Research progress of nitrate removal from water via capacitive deionization

Abstract

Capacitive deionization(CDI) is a new electrochemical nitrate removal technology, which has the advantages of simple structure and operation, low cost, low energy consumption and environmental friendliness. However, there are problems such as insufficient adsorption capacity, poor selectivity and limited desalting capacity. In view of the problems in CDI, scholars have carried out in-depth research on the structure optimization of CDI device and the modification of electrode materials. The research progress of CDI device structure optimization including membrane capacitance deion technology (MCDI), flow electrode capacitance deion technology (FCDI), capacitance-electrocatalytic coupling technology, etc was introduced. The research progress of electrode material modification was mainly introduced from the aspects of resin coating, surface modification, metal oxide/hydroxide doping, and structure regulation. The analysis showed that the CDI device structure optimization and electrode material modification improved the performance of the technology to remove nitrate and expanded the application range of the technology to remove nitrate, which made the CDI technology had a very broad application prospect in the removal of nitrate. Finally, some suggestions were proposed to provide reference for the further development of CDI from the aspects of improving the selectivity and removal rate, increasing the adsorption capacity of electrode, enhancing the sustainable utilization of electrode and practical application.

Keywords

• capacitive deionization
• electrode modification
• structural optimization
• nitrate