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DESCRIPTION
Capacitive deionization
(CDI) with carbon-aerogel electrodes is an
efficient and economical new process for removing salt and impurities from water. In the
process, water is passed between electrodes kept at a potential difference of about one
volt; nonreducible and nonoxidizable ions are removed from the water by the imposed
electrostatic field and held at the electrode surfaces. When the electrodes become
saturated with salt, they are electrostatically "regenerated," releasing the
salts into a concentrated purge stream.
Carbon-aerogel electrodes have excellent stability in harsh chemical
conditions and a very high specific surface area (600–1000 square meters per gram of
aerogel), which enables the design of robust yet compact purifying systems. Carbon
aerogels were developed at LLNL and are now in commercial production. Their cost should
drop considerably as their use in this and other applications increases. Some of the
energy used in ion removal can be recovered during regeneration, improving overall energy
efficiency.
STATUS:
The CDI patent was issued in 1995. The Laboratory is
actively looking for industrial partners with whom to further develop and scaleup the
technology.
CONTACT
Annemarie Meike
Lawrence
Livermore National Laboratory
Phone: (925) 422-3735
Fax: (925) 423-8988
E-mail: meike1@llnl.gov
Mail code: L-795
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