Integrating a supercapacitor with capacitive deionization for direct energy recovery from the desalination of brackish water

Yu-Wu Chen, Jhao-Fu Chen, Chang-Hua Lin and Chia-Hung Hou

Applied Energy, 2019, vol. 252, issue C, -

Abstract: The importance of energy recovered from desalination techniques has been of considerable interest because of increasing water scarcity and energy crises. Capacitive deionization (CDI), a promising desalination technology using pairs of carbon electrodes under an electric field, has an attractive advantage in that energy stored during the charging step for salt removal can be further recovered during the discharging step. In this research, an energy recovery system based on a four-switch buck-boost converter with variable frequency was successfully constructed to transfer electric energy from a CDI module to a supercapacitor. The effects of the influent NaCl concentration and the distance between two oppositely placed electrodes were investigated on both the desalination behavior and energy recovery performance. The experimental procedure involved a charging step for ion removal, stop-flow operation for energy recovery, and discharging step for electrode regeneration. For the desalination of a 10 mM NaCl solution, a deionization capacity of 10.1 mg g−1 and a total energy input of 0.09 kWh m−3 were obtained. Overall, as demonstrated, a higher energy recovery ratio was achieved with a higher influent NaCl concentration and a shorter distance between the two electrodes. Significantly, up to 49.6% of the energy stored in the CDI module while reducing the salinity of a 50 mM NaCl solution could be directly recovered, indicating that the energy recovery system based on a four-switch buck-boost converter shows superior performance. The utilization of CDI integrated with a supercapacitor in this work holds great potential in both low-energy-requirement desalination and high-efficiency energy storage.

Keywords: Capacitive deionization; Energy storage; Energy recovery; Desalination; Four-switch buck-boost converter (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261919310918
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:252:y:2019:i:c:29

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic

DOI: 10.1016/j.apenergy.2019.113417

Access Statistics for this article

Applied Energy is currently edited by J. Yan

More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().