Low-Resistant Ion-Exchange Membranes for Energy Efficient Membrane Capacitive Deionization
Membrane capacitive deionization (MCDI) has emerged as an effective and energy efficient desalination technology for treating brackish water streams used in numerous industrial processes. Most material research studies on MCDI focus on improving the porous electrodes or using flowing electrode architectures, and little emphasis is given to the rationale design of ion-exchange membranes (IEMs) for MCDI. In this work, the ionic conductivity, permselectivity, and thickness for three different IEM chemistries (polyaliphatic, poly(arylene ether), and perfluorinated) were correlated to MCDI performance attributes: energy expended per ion removed, salt removal efficiency, and Coulombic efficiency. A 5- to 10-fold reduction in area specific resistance, which accounts for thickness and ionic conductivity, with unconventional perfluorinated and poly(arylene ether) IEMs reduced the energy expended per ion removed in MCDI by a factor of 2 when compared to conventional electrodialysis IEMs. In situ electrochemical impedance spectroscopy substantiated that thinner membranes with higher ionic conductivity helped in the reduction of energy expended per ion removed (more than 50%). Lastly, the lower than 100% Coulombic efficiency is ascribed to carbon corrosion of the porous electrodes highlighting that further improvements in MCDI do not just necessitate more appropriate membranes but corrosion resilient electrodes. KEYWORDS: Desalination, Ion-exchange membranes, Membrane capacitive deionization
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1501878
- Journal Information:
- ACS Sustainable Chemistry & Engineering, Vol. 6, Issue 11; ISSN 2168-0485
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Emerging investigator series: capacitive deionization for selective removal of nitrate and perchlorate: impacts of ion selectivity and operating constraints on treatment costs
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journal | January 2020 |
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