November 28, 2016

Researchers Turn Ordinary Fibers Into Water, Air Purifiers

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For centuries, rivers have sustained human civilization. From the Nile to the Indus, these blue-green and brown waters have been invaluable sources of irrigation. Unfortunately, they are equally convenient for waste disposal. Over time, cocktails of industrial effluents have caused these rivers to acquire much darker hues. Fortunately, Prof. Juan Hinestroza, fiber science, has created a pollutant-absorbing fiber that could help restore rivers to their former glory.

“I often know what color is in fashion in the U.S. by looking at a river because some of the chemicals used in manufacturing are thrown into lakes and rivers,” Hinestroza said. It’s so sad because people have to drink this water. As a result, what we wanted to do is create a material that could capture pollutants from air and water.”

Hinestroza developed the polymer using a process known as cyclodextrin polymerization to coat the surface of a cotton fabric. Polymerization is the process of reacting molecules together in a chemical reaction to form polymers, large molecules of repeated subunits. The resultant material is capable of filtering a variety of contaminants, including Styrene and Bisphenol A. BPA is known to cause a variety of negative health effects, including breast cancer, early puberty, heart disease and infertility.

“Cyclodextrin is a very beautiful molecule. On the outside it’s hydrophobic and on the inside it’s hydrophilic,” Hinestroza explained. “It works because of the chemical affinity of the molecule – it is able to capture the pollutants inside and reuse them.”

He uses the analogy of a cup to explain how the polymer captures these pollutants.

“The polymer is like a little cup. When we put the cups together the contaminant gets captured. We can release the pollutants by changing the pressure or heating it up slowly,” Hinestroza said.That’s an advantage because we can reuse the polymer.”

Hinestroza’s polymer has numerous other advantages over those that already exist. For example, companies can easily incorporate it into their manufacturing processes without needing to procure new machines or make special changes to manufacturing conditions.

“I think the main advantage of our polymer is that we can capture the pollutants extremely fast,” Hinestroza said. “We decided to benchmark our polymer with commercial solvents and we ended up being several orders of magnitude faster in capturing large amounts of pollutants without saturation.”

The process is not exclusive to cotton. Cotton was only chosen as the testing material due to its common use and low level of testing difficulty.

“We can coat polyester, we can coat nylon, we can coat any other textile fiber,” Hinestroza said. “Once you have it as a fiber, you can produce a t-shirt, a filter, a carpet, a curtain, anything. All these different objects can clean the air.”

Hinestroza said he hopes that such polymers will eventually be used in other industries as well.

“We want to see it become much bigger than the textile industry. It will be nice to have clothing that can clean water and air, but we also see these filtering juices, packaging food and as architectural textiles,” Hinestroza said.

In fact, one of Hinestroza’s main goals is to develop a ‘super-suit’ capable of repelling stains, changing colors and healing minor wounds.

“We work on interactive textiles, so cleaning the air and water is only one aspect. We are also working on clothing that changes colors without pigments. For example, when there is an allergen close by, the clothing will change colors to alert you. If someone spills wine on the clothing, it should be able to repel the stain and scent.”