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Concentration‐Gradient Multichannel Flow‐Stream Membrane Capacitive Deionization Cell for High Desalination Capacity of Carbon Electrodes
Author(s) -
Kim Choonsoo,
Lee Juhan,
Srimuk Pattarachai,
Aslan Mesut,
Presser Volker
Publication year - 2017
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201700967
Subject(s) - capacitive deionization , desalination , adsorption , electrode , membrane , capacitance , activated carbon , desorption , chemistry , analytical chemistry (journal) , chemical engineering , materials science , chromatography , biochemistry , organic chemistry , engineering
We present a novel multichannel membrane flow‐stream capacitive deionization (MC‐MCDI) concept with two flow streams to control the environment around the electrodes and a middle channel for water desalination. The introduction of side channels to our new cell design allows operation in a highly saline environment, while the feed water stream in the middle channel (conventional CDI channel) is separated from the electrodes with anion‐ and cation‐exchange membranes. At a high salinity gradient between side (1000 m m ) and middle (5 m m ) channels, MC‐MCDI exhibited an unprecedented salt‐adsorption capacity (SAC) of 56 mg g −1 in the middle channel with charge efficiency close to unity and low energy consumption. This excellent performance corresponds to a fourfold increase in desalination performance compared to the state‐of‐the‐art in a conventional CDI cell. The enhancement originates from the enhanced specific capacitance in high‐molar saline media in agreement with the Gouy–Chapman–Stern theory and from a double‐ion desorption/adsorption process of MC‐MCDI through voltage operation from −1.2 to +1.2 V.