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Title: The use of carbon aerogel electrodes for environmental cleanup

Abstract

A process for the capacitive deionization (CDI) of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory. Earlier versions of CDI use activated carbon as electrodes. Aqueous solutions with various anions and canons are passed through a stack of carbon aerogel electrodes, each having a very high specific surface area (400 to 1100 m{sup 2}/g). After polarization, non-reducible and non-oxidizable ions are removed from the electrolyte by the imposed electric field and held in electric double layers formed at the surfaces of electrodes. As desired, the effluent from the cell is purified water. This process is also capable of simultaneously removing a variety of other impurities. Dissolved heavy metals and suspended colloids can be removed by electrodeposition and electrophoresis, respectively. CDI has several potential advantages over other more conventional technologies. Unlike ion exchange, no acids, bases, or salt solutions are required for regeneration of the system. Regeneration is accomplished by electrically discharging the cell. Therefore, no secondary waste is generated. In contrast to thermal processes such as evaporation, CDI is much more energy efficient. Since no membranes or high pressure pumps are required, CDI offers operational advantages over electrodialysis and reverse osmosis (RO).more » Carbon aerogel capacitive deionization can produce a continuous flow of product water by operating two stacks of carbon aerogel electrodes in parallel. One stack purifies while the other is electrically regenerated. This mode of operation is call potential swing and also enables energy recovery. For example, energy released during the discharge of one stack of electrodes (regeneration) can be used to charge the other stack (deionization). Such synchronous operation requires user-friendly automation This level of automation and sophistication has been incorporated into the demonstration process now available at LLNL.« less

Publication Date:
OSTI Identifier:
370424
Report Number(s):
CONF-960376-
TRN: 96:003805-0476
Resource Type:
Conference
Resource Relation:
Conference: Spring national meeting of the American Chemical Society (ACS), New Orleans, LA (United States), 24-28 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of 211th ACS national meeting; PB: 2284 p.
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; COLLOIDS; REMOVAL; METALS; WASTE WATER; WASTE PROCESSING; ACTIVATED CARBON; ANIONS; AQUEOUS SOLUTIONS; ELECTRODES; ION EXCHANGE; MEMBRANES; SPECIFIC SURFACE AREA; SEPARATION PROCESSES; ENERGY RECOVERY; ENERGY CONSUMPTION; ELECTRIC FIELDS

Citation Formats

. The use of carbon aerogel electrodes for environmental cleanup. United States: N. p., 1996. Web.
. The use of carbon aerogel electrodes for environmental cleanup. United States.
. Tue . "The use of carbon aerogel electrodes for environmental cleanup". United States.
@article{osti_370424,
title = {The use of carbon aerogel electrodes for environmental cleanup},
author = {},
abstractNote = {A process for the capacitive deionization (CDI) of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory. Earlier versions of CDI use activated carbon as electrodes. Aqueous solutions with various anions and canons are passed through a stack of carbon aerogel electrodes, each having a very high specific surface area (400 to 1100 m{sup 2}/g). After polarization, non-reducible and non-oxidizable ions are removed from the electrolyte by the imposed electric field and held in electric double layers formed at the surfaces of electrodes. As desired, the effluent from the cell is purified water. This process is also capable of simultaneously removing a variety of other impurities. Dissolved heavy metals and suspended colloids can be removed by electrodeposition and electrophoresis, respectively. CDI has several potential advantages over other more conventional technologies. Unlike ion exchange, no acids, bases, or salt solutions are required for regeneration of the system. Regeneration is accomplished by electrically discharging the cell. Therefore, no secondary waste is generated. In contrast to thermal processes such as evaporation, CDI is much more energy efficient. Since no membranes or high pressure pumps are required, CDI offers operational advantages over electrodialysis and reverse osmosis (RO). Carbon aerogel capacitive deionization can produce a continuous flow of product water by operating two stacks of carbon aerogel electrodes in parallel. One stack purifies while the other is electrically regenerated. This mode of operation is call potential swing and also enables energy recovery. For example, energy released during the discharge of one stack of electrodes (regeneration) can be used to charge the other stack (deionization). Such synchronous operation requires user-friendly automation This level of automation and sophistication has been incorporated into the demonstration process now available at LLNL.},
doi = {},
url = {https://www.osti.gov/biblio/370424}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {10}
}

Conference:
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