Improved desalination performance of flow-electrode capacitive deionisation by a novel drop-shape channel

ABSTRACT

As an emerging desalination technology, flow-electrode capacitive deionisation (FCDI) has the advantages of theoretically infinite adsorption capacity and applicability to high-concentration brine. However, during the operation of FCDI, the flow electrode in the S-shape channel is prone to sedimentation and clogging the channel. This undesirable phenomenon brings low efficiency and security issues. Therefore, a drop-shape channel was designed for FCDI to improve the flow regime of the flow electrode. The flow simulation of the drop-shape channel was performed to select the appropriate geometry to avoid the formation of the vortex and low-velocity region. The simulation results showed that the streamlined design of the drop-shape channel has insignificant velocity gradients. It significantly reduces the low-velocity region and improves the phenomenon of particle sedimentation. The desalination performance with varieties of electrode flow rate, AC content, and voltage was used to investigate the advantage between S-shape and drop-shape channels. It was found that under the conditions of low flow rate, high AC content, and high voltage, the drop-shape channel FCDI system could still obtain better ASRR and CE.

GRAPHICAL ABSTRACT

KEYWORDS:

• Flow-electrode capacitive deionisation
• flow electrode
• flow channel
• flow simulation
• brackish water desalination

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author.

Additional information

Funding

This work was supported by the Liaoning Revitalization Talents Program [grant number XLYC2007170]; ‘Jie Bang Gua Shuai’ Key Technologies R&D Program of Liaoning Province [grant number 2021JH1/10400031]; Scientific research fund project of Liaoning Provincial Department of Education [grant numbers LJKZ0154, LJKMZ20220499, LJKQZ20222299]; Liaoning Applied Basic Research Program [grant number 2022JH2/101300121]; Liaoning Provincial Joint Foundation [grant number 2023-MSLH-257].