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Capacitive Deionization of Divalent Cations for Water Softening Using Functionalized Carbon Electrodes.

ABSTRACT: Water softening is a relatively untapped area of research in capacitive deionization (CDI). In this work, we demonstrate how an asymmetric combination of oxidized and aminated carbon can be used for selective removal of divalent cations for water softening. We first show how higher electrosorption performances can be achieved in single-salt experiments involving NaCl, KCl, MgCl2, and CaCl2 before proceeding to multi-salt experiments using different combinations of the four salts. The salt combinations are chosen to investigate one of the three factors: (1) ionic mass, (2) ionic charge, or (3) concentration. We show how divalent selectivity can be achieved due to high local electrostatic attraction between negatively charged oxygen moieties and divalent cations. Additionally, an ion-exchange process between the oxidized carbon surface and cations can result in lower pH values, which prevent the precipitation of scale-forming ions.

SUBMITTER: Leong ZY

PROVIDER: S-EPMC7016927 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Capacitive Deionization of Divalent Cations for Water Softening Using Functionalized Carbon Electrodes.

Leong Zhi Yi ZY Yang Hui Ying HY

ACS omega 20200128 5

Water softening is a relatively untapped area of research in capacitive deionization (CDI). In this work, we demonstrate how an asymmetric combination of oxidized and aminated carbon can be used for selective removal of divalent cations for water softening. We first show how higher electrosorption performances can be achieved in single-salt experiments involving NaCl, KCl, MgCl<sub>2</sub>, and CaCl<sub>2</sub> before proceeding to multi-salt experiments using different combinations of the four ...[more]

PMID: 32064370

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