Carbon nanotubes enlisted to reduce waste in cleanup of toxic chemicals
"Researchers at Pacific Northwest National Laboratory have demonstrated a new, environmentally friendly process for treating water contaminated by perchlorate ....
The conventional method for treating perchlorate-contaminated water employs an ion exchange resin. Regenerating the resin requires flushing with an acidic solution, which results in large quantities of secondary waste.
The PNNL method is an electrically controlled anion exchange process. The technology is unique in that it uses an electric current to regenerate the resin and release the perchlorate without producing a lot of secondary waste ...To create the new process, Lin and his colleagues induced a positive charge to an electrically conducting polymer, such as a polypyrrole, that selectively attracts the negatively charged perchlorate ions. Application of an electric current releases the trapped perchlorate ions for disposal. Now neutral, the polymer can be reverted to a positively charged surface and re-used.
The scientists increased the amount of perchlorate that can be captured by depositing the polymer as a polypyrrole thin film on a matrix of carbon nanotubes, creating a porous conductive nanocomposite."
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