Low energy consumption flow capacitive deionization with a combination of redox couples and carbon slurry

Qiang Wei, Yudi Hu, Jian Wang, Qiang Ru, Xianhua Hou, Lingzhi Zhao, Denis Y. W. Yu, Kwan San Hui, Dongliang Yan, Kwun Nam Hui, Fuming Chen

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Abstract

Flow-electrode capacitive deionization (FCDI) is a new sustainable desalination technology where continuous desalination can be achieved by the electrodialysis coupling method. However, its development is hindered owing to high energy consumption and low salt removal rate. Herein, by combining ferri-/ferrocyanide redox couple with flow activated carbon (AC)/carbon black (CB) slurry, continuous desalination process is achieved with a high salt removal rate of 1.31 μg cm-2 s-1 and low energy consumption of 102.68 kJ mol-1 at the current density 2.38 mA cm-2 (50 mA current for a 21 cm2 active area). The operating voltage plateau can be reduced to 0.69 V when 10 wt% AC/CB (mass ratio of 9:1) is mixed with 20 mM/20 mM ferri-/ferrocyanide as the flow electrodes, compared with more than 3 V for only carbon flow or redox medium alone. The influences of carbon content and current densities are further investigated to so that the performances can be controlled. This work enables the development of energy-saving desalination systems by coupling FCDI with redox desalination technique.
Original languageEnglish
Pages (from-to)487-492
Number of pages6
JournalCarbon
Volume170
Early online date19 Aug 2020
DOIs
Publication statusPublished - Dec 2020

Keywords

  • Activated carbon/carbon black
  • Electrochemical desalination
  • Flow-electrode capacitive deionization
  • Redox desalination

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