Seawater reverse osmosis (SWRO) is usually combined with brackish reverse osmosis (BWRO) to improve the water quality in seawater desalination; however, this configuration often results in high energy consumption. Consequently, membrane capacitive deionization (MCDI) has been suggested as a lower energy alternative technology, but cyclic operation within the cell (i.e., discontinuous operation of ad/desorption) is a main disadvantage. On the other hand, flow electrode capacitive deionization (FCDI) can be continuously operated by using a flow electrode. In this study, the feasibility of a SWRO-FCDI system was examined by using a suitable electrolyte in the flow electrode: seawater or SWRO concentrate. In addition, by employing a selective ion exchange membrane (IEM), the FCDI was able to selectively remove monovalent ions rather than divalent ions, unlike BWRO, thus producing a final product water containing divalent ions, which is more suitable for corrosion control in the subsequent pipe distribution systems. As a result, the remineralization process can be minimized. To test the SWRO-FCDI concept, actual SWRO permeate was first treated in a single mode with an electrolyte comprising real seawater in a flow electrode, and the feasibility of long-term operation was proven by batch-mode, which allowed the optimization of the FCDI active area.
Bibliographical noteFunding Information:
This work was supported by Korea Environment Industry & Technology Institute ( KEITI ) through Industrial Facilities & Infrastructure Research Program, funded by Korea Ministry of Environment (MOE) ( 1485016424 ).
This work was supported by Korea Environment Industry & Technology Institute (KEITI) through Industrial Facilities & Infrastructure Research Program, funded by Korea Ministry of Environment (MOE) (1485016424).
© 2020 Elsevier B.V.
- Flow electrode capacitive deionization (FCDI)
- Flow electrodes
- Perm-selective ion exchange membrane (IEM)
- Seawater reverse osmosis (SWRO) desalination
- Specific energy consumption (SEC)
ASJC Scopus subject areas
- Chemical Engineering(all)
- Materials Science(all)
- Water Science and Technology
- Mechanical Engineering