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Title: The use of carbon aerogel electrodes for environmental cleanup

Abstract

An electrochemical cell with a stack of carbon aerogel electrodes has been used to remove a variety of contaminants from aqueous waste streams and natural waters. In the case of non-reducible and non-oxidizable salt solutions, the cell is operated in a capacitive mode. Electrolytic or electrophoretic deposition is used for the removal of heavy metals. The removal of NaNO{sub 3} from water with subsequent concentration is an example of capacitive operation. Electrodialysis with bipolar membra Na{sup +}s can be used to separate neutral salt solutions into their acid and base components so that recycle is possible, thereby lowering risk to the environment. Carbon aerogel electrodes can be used to remove NaNO{sub 3} from the effluent, concentrating it for recycle to the electrodialysis cell. Solutions are passed through a stack of carbon aerogel electrodes, each having a very high specific surface area (400 to 1100 m{sup 2} g{sup -1}) and very low electrical resistivity (less than 40 m{Omega}-cm). After polarization, Ne cations and NO{sub 3}-anions are removed from the electrolyte by the imposed electric field and held in electric double layers formed at the surfaces of electrodes. Two streams are produced, pure water and NaNO{sub 3} concentrate. This process is alsomore » capable of removing other impurities such as dissolved heavy metals and suspended colloids. In these cases, contaminants are removed by electrodeposition and electrophoresis, respectively. The carbon aerogel cell has been used for the separation of copper, zinc, cadmium, and lead from 0.1 M KNO{sub 3} solutions, as well as for the separation of cobalt, chromium, manganese, lead, and uranium from sea water. Treatability tests on ground water at LLNL have shown that chromium contamination can be reduced from 32 to 2 ppb, well below the acceptable level of 11 ppb.« less

Authors:
; ; ;  [1]
  1. Lawrence Livermore National Lab., CA (United States); and others
Publication Date:
OSTI Identifier:
433175
Report Number(s):
CONF-960376-
Journal ID: ACFPAI; ISSN 0569-3772; TRN: 97:000008-0096
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Preprints of Papers, American Chemical Society, Division of Fuel Chemistry
Additional Journal Information:
Journal Volume: 41; Journal Issue: 1; Conference: Spring national meeting of the American Chemical Society (ACS), New Orleans, LA (United States), 24-28 Mar 1996; Other Information: PBD: 1996
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 36 MATERIALS SCIENCE; GROUND WATER; REMEDIAL ACTION; CHROMIUM; REMOVAL; CARBON; SORPTIVE PROPERTIES; NITRATES; ANIONS; ELECTRODES; SPECIFIC SURFACE AREA; SURFACES

Citation Formats

Farmer, J C, Fix, D V, Pekala, R W, and Nielsen, J K. The use of carbon aerogel electrodes for environmental cleanup. United States: N. p., 1996. Web.
Farmer, J C, Fix, D V, Pekala, R W, & Nielsen, J K. The use of carbon aerogel electrodes for environmental cleanup. United States.
Farmer, J C, Fix, D V, Pekala, R W, and Nielsen, J K. Tue . "The use of carbon aerogel electrodes for environmental cleanup". United States.
@article{osti_433175,
title = {The use of carbon aerogel electrodes for environmental cleanup},
author = {Farmer, J C and Fix, D V and Pekala, R W and Nielsen, J K},
abstractNote = {An electrochemical cell with a stack of carbon aerogel electrodes has been used to remove a variety of contaminants from aqueous waste streams and natural waters. In the case of non-reducible and non-oxidizable salt solutions, the cell is operated in a capacitive mode. Electrolytic or electrophoretic deposition is used for the removal of heavy metals. The removal of NaNO{sub 3} from water with subsequent concentration is an example of capacitive operation. Electrodialysis with bipolar membra Na{sup +}s can be used to separate neutral salt solutions into their acid and base components so that recycle is possible, thereby lowering risk to the environment. Carbon aerogel electrodes can be used to remove NaNO{sub 3} from the effluent, concentrating it for recycle to the electrodialysis cell. Solutions are passed through a stack of carbon aerogel electrodes, each having a very high specific surface area (400 to 1100 m{sup 2} g{sup -1}) and very low electrical resistivity (less than 40 m{Omega}-cm). After polarization, Ne cations and NO{sub 3}-anions are removed from the electrolyte by the imposed electric field and held in electric double layers formed at the surfaces of electrodes. Two streams are produced, pure water and NaNO{sub 3} concentrate. This process is also capable of removing other impurities such as dissolved heavy metals and suspended colloids. In these cases, contaminants are removed by electrodeposition and electrophoresis, respectively. The carbon aerogel cell has been used for the separation of copper, zinc, cadmium, and lead from 0.1 M KNO{sub 3} solutions, as well as for the separation of cobalt, chromium, manganese, lead, and uranium from sea water. Treatability tests on ground water at LLNL have shown that chromium contamination can be reduced from 32 to 2 ppb, well below the acceptable level of 11 ppb.},
doi = {},
journal = {Preprints of Papers, American Chemical Society, Division of Fuel Chemistry},
number = 1,
volume = 41,
place = {United States},
year = {1996},
month = {12}
}