Hybrid capacitive deionization to enhance the desalination performance of capacitive techniques

다국어 초록 (Multilingual Abstract)

<P>Based on a porous carbon electrode, capacitive deionization (CDI) is a promising desalination technology in which ions are harvested and stored in an electrical double layer. However, the ion removal capacity of CDI systems is not sufficient for desalting high-concentration saline water. Here, we report a novel desalination technique referred to as “hybrid capacitive deionization (HCDI)”, which combines CDI with a battery system. HCDI consists of a sodium manganese oxide (Na<SUB>4</SUB>Mn<SUB>9</SUB>O<SUB>18</SUB>) electrode, an anion exchange membrane, and a porous carbon electrode. In this system, sodium ions are captured by the chemical reaction in the Na<SUB>4</SUB>Mn<SUB>9</SUB>O<SUB>18</SUB> electrode, whereas chloride ions are adsorbed on the surface of the activated carbon electrode during the desalination process. HCDI exhibited more than double the ion removal sorption capacity (31.2 mg g<SUP>−1</SUP>) than a typical CDI system (13.5 mg g<SUP>−1</SUP>). Moreover, it was found that the system has a rapid ion removal rate and excellent stability in an aqueous sodium chloride solution. These results thus suggest that the HCDI system could be a feasible method for desalting a highly concentrated sodium chloride solution in capacitive techniques.</P>

<P>Graphic Abstract</P><P>Based on a porous carbon electrode, capacitive deionization (CDI) is a promising desalination technology in which ions are harvested and stored in an electrical double layer.
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