Nanoparticles, super-absorbent gel clean radioactivity from porous
structures
ARGONNE, Ill. (July 2, 2004) – Porous structures, such as brick
and concrete, are notoriously hard to clean when contaminated with
certain types of radioactive materials. Now, thanks to researchers
in Argonne's Chemical Engineering
Division, a new technique is being developed that can effectively
decontaminate these structures in the event of exposure to radioactive
elements.
Researchers are using engineered nanoparticles and a super-absorbent
gel to design a clean-up system for buildings and monuments exposed
to radioactive materials. Having this system available will allow
the nation to be more prepared in case of a terrorist attack with
a “dirty bomb” or other radioactive dispersal device.
“If a radioactive device were activated in public, the primary
concern would be widespread contamination,” said Michael Kaminski,
lead scientist of the project. “This contamination is particularly
hard to remove in buildings made from brick or concrete, where
the pores, or holes, in those materials make it easy for radioactive
materials to become trapped.”
Enter Kaminski and his team of Argonne scientists, whose decontamination
system could safely capture and dispose of radioactive elements
in porous structures in an outdoor environment. Using a simple,
three-step procedure, the system operates much like an automated
car wash, where remote spray washers apply a wetting agent and
a super-absorbent gel onto the contaminated surface. The wetting
agent causes the bound radioactivity to resuspend in the pores.
The super-absorbent polymer gel then draws the radioactivity out
of the pores, and fixes it in the engineered nanoparticles that
sit in the gel. Finally, the gel is vacuumed and recycled, leaving
only a small amount of radioactive waste.
“The polymer gel we use to absorb the radioactivity is similar
to the absorbent material that's found in disposable diapers,” Kaminski
explained. “When exposed to a wetting agent, the polymers start
to cross-link, forming something like a structural scaffold that
allows the gel to absorb an incredible amount of liquid.”
The Argonne technique would overcome many of the shortcomings
of current radioactive decontamination operations.
“Right now, it is common practice to demolish the contaminated
materials in hopes of getting rid of the radioactivity. Our technique
would allow surfaces to be preserved, which means that we wouldn't
have to deface monuments or buildings just to remove the radiation,” said
Kaminski.
The group has 18 months to complete development of the decontamination
method. The project will culminate in a prototype demonstration
of the technology using real contaminated concrete samples. This
work is being done as part of an interagency Technical Support
Working Group project selected from more than 3,000 submitted in
May 2003 and funded by the Department
of Homeland Security.
Kaminski's group is also developing other technologies for biomedical
and military applications, using magnetic nanoparticles. Experience
in that work, funded by the U.S. Department of Energy, led to the
super-absorbent gel project and other work for defense and homeland
security applications.
"Within our group, we are combining our experience from the past
several years in areas of nuclear power plant decontamination, engineered
nanoparticles and polymer gels to develop this new decontamination
technology," Kaminski says. "It has provided a potential solution
to one of the key challenges in counter-terrorism."
Argonne National Laboratory brings
the world's brightest scientists and engineers together to find exciting and
creative new solutions to pressing national problems in science and technology.
The nation's first national laboratory, Argonne conducts leading-edge basic
and applied scientific research in virtually every scientific discipline. Argonne
researchers work closely with researchers from hundreds of companies, universities,
and federal, state and municipal agencies to help them solve their specific
problems, advance America 's scientific leadership and prepare the nation for
a better future. With employees from more than 60 nations, Argonne is managed
by UChicago
Argonne, LLC for
the U.S.
Department of Energy's Office
of Science.
— Margret
Chang
For more information, please contact Steve McGregor (630/252-5580
or media@anl.gov) at Argonne.
|