Turning Nitrates into Harmless Water and Air


Photo by: JJ Harrison via Wikimedia Commons


Toxic nitrates from drinking are have been cleaned and converted into air and water by engineers at Rice University's Nanotechnology Enabled Water Treatment Center. 

Nitrates are molecules that have one nitrogen atom and three oxygen atoms that turn into nitrite like the ones used to preserve meats when they lose an oxygen atom.

Nitrates come mostly from runoff by agricultural farming communities everywhere and both nitrates and nitrites are toxic. However, Rice Chemical Engineer Michael Wong says that nitrites are toxic but "nitrates are the more prevalent problem."

Nitrates are not only toxic and but may also be carcinogenic. Infants and women are often the groups most susceptible to these like in the Corn Belt and California's Central Valley where fertilizers are in heavy use. 

Engr. Wong says that "the best way to remove nitrates is a catalytic process that breaks them completely apart into nitrogen and oxygen."

Wong's lab develops nanoparticle-based catalysts that speed up chemical reactions. His group has shown in 2013 that tiny gold spheres dotted with palladium are able to break down nitrites (which are the more toxic cousin of nitrates) but are not that good enough.

Together with research co-author Kim Heck, they were able to find another alternative using indium and palladium as they searched scientific literature.

Collaborating with colleague chemical engineers Jeffrey Miller of Purdue University and Lars Grabow of the University of Houston, the team from Rice University found that the indium was able to speed up the nitrate breakdown while the palladium kept the indium from undergoing total oxidation.

They plan to add the process into commercially viable water-treatment systems as they will be working with industrial partners and other researchers.

"NEWT is all about taking basic science discoveries and getting them deployed in real-world conditions," says Wong as he adds that they have already figured out the chemistry and that the next step is proof of concept after which it can already be used.