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Confined Redox Reactions of Iodide in Carbon Nanopores for Fast and Energy‐Efficient Desalination of Brackish Water and Seawater
Author(s) -
Lee Juhan,
Srimuk Pattarachai,
Carpier Sidonie,
Choi Jaehoon,
Zornitta Rafael Linzmeyer,
Kim Choonsoo,
Aslan Mesut,
Presser Volker
Publication year - 2018
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.201801538
Subject(s) - desalination , chemistry , capacitive deionization , seawater , redox , brackish water , electrochemistry , chemical engineering , inorganic chemistry , membrane , electrode , salinity , ecology , biochemistry , oceanography , engineering , biology , geology
Abstract Faradaic deionization is a promising new seawater desalination technology with low energy consumption. One drawback is the low water production rate as a result of the limited kinetics of the ion intercalation and insertion processes. We introduce the redox activities of iodide confined in carbon nanopores for electrochemical desalination. A fast desalination process was enabled by diffusionless redox kinetics governed by thin‐layer electrochemistry. A cell was designed with an activated carbon cloth electrode in NaI aqueous solution, which was separated from the feedwater channel by a cation‐exchange membrane. Coupled with an activated carbon counter electrode and an anion‐exchange membrane, the half‐cell in NaI with a cation‐exchange membrane maintained performance even at a high current of 2.5 A g −1 (21 mA cm −2 ). The redox activities of iodide allowed a high desalination capacity of 69 mg g −1 (normalized by the mass of the working electrode) with stable performance over 120 cycles. Additionally, we provide a new analytical method for unique performance evaluation under single‐pass flow conditions regarding the water production rate and energy consumption. Our cell concept provides flexible performance for low and high salinity and, thus, enables the desalination of brackish water or seawater. Particularly, we found a low energy consumption (1.63 Wh L −1 ) for seawater desalination and a high water production rate (25 L m −2 h −1 ) for brackish water.