New polymer could greatly improve water purification

Materials scientists at Cornell University have created a new polymer with tremendous water purification abilities.

The new polymer is a porous form of cyclodextrin, a cornstarch derivative used in air fresheners to trap odorous particles. When deployed in contaminated water, the material absorbs pollutants at rates up to 200 times more efficient than traditional water purification technologies.

Most water treatment technologies use activated carbons. These materials have larger surface areas for pollutants to bind to, but they don't attract contaminant particles as efficiently. The new porous form of cyclodextrin has more space to trap toxins than previous versions.

"What we did is make the first high-surface-area material made of cyclodextrin, combining some of the advantages of the activated carbon with the inherent advantages of the cyclodextrin," lead researcher Will Dichtel, associate professor of chemistry and chemical biology at Cornell, explained in a press release.

"When you combine the best features of those two materials, you get a material that's even better than either class," Dichtel said. "These materials will remove pollutants in seconds, as the water flows by, so there's a potential for really low-energy, flow-through water purification, which is a big deal."

Dichtel is a 2015 MacArthur Foundation Fellowship winner. He says part of his $650,000 in award money -- spread out over five years -- will fund continued research into the water purification powers of cyclodextrin.

He and his colleagues are now working on integrating the material into a scalable water-treatment device, a machine that could be used to clean wastewater at an industrial scale.

The promise of cyclodextrin is detailed in a new paper, published this week in the journal Nature.

Another advantage of cyclodextrin is that it's recyclable. Activated carbon requires a high-intensity heat treatment to reactivate its water-cleaning properties. Cyclodextrin can be cleaned with methanol or ethanol at room temperature without a drop in performance.