by Tim Terman
The author is associate director of the
WVU News and Information Services Office.For Richard Turton, it's a sticky issue.
If a new product for air and water filtration devices is to work, it has to adhere to polymer carrier particles about the size of BB gun pellets. Turton's job is to find a binder to make the product stick so that it can't be easily flushed off in flowing water. And it has to cling to the BB carrier in such a way that it doesn't diminish the product's effectiveness.
If Dr. Turton can solve this problem, then the water and air filter industry may have a revolutionary new product that could change the way disinfectants are applied in fighting diseases such as tuberculosis and Legionnaires' disease.
The quest began with Dr. Dave Worley of Auburn University, who developed what is known as polystyrenehydantoin, or Poly1, which contains a chemical that can almost instantly kill disease-causing bacteria and viruses. The product could be used in spas, slaughterhouses, oil refineries, nurseries, operating rooms, airplanes, restaurants, state parks, and even war zones.
"I don't use the word lightly, but this really is a product that could revolutionize water and air treatment," Turton said. "There are myriad uses for it."
Worley and his colleague, Dr. Gang Sun of the University of California-Davis, were able to attach a soluble stabilizer used in spas and swimming pools to a nonsoluble plastic (polystyrene), thereby making a nonsoluble stabilizer, which they call Poly1. This polymer, attached to the BB-sized carrier, contains molecules from the family of chemicals known as halogens (typically chlorine and bromine), which are effective germ killers.
So, instead of a swimming pool being treated with frequent doses of liquid chlorine, water would flow through a filter equipped with the halogen compound contained in Poly1. Turton's binder, a critical element of the system, holds the Poly1 to the larger carrier particles, and germs are killed by the millions--without chemicals being directly applied to the water. "Most treatment of bacteria in swimming pools involves adding chlorine," Turton said. "The big difference with the Poly1 method is that the chlorine is bonded to a polymer, not added to the water. And a big plus is that Poly1 can be recharged simply by being soaked in a mild bleach solution for about half an hour."
It's like killing insects. The filter will be like one of those electric insect eliminators that disturb the summer evenings, zapping unwary mosquitoes and moths in a deadly ultraviolet glow. That's the way the biocidal polymer, as it's called, would work, zapping bacteria and germs as they flow through the filter. Current water treatment works like an insect spray, adding a chemical to the environment in the hope that the offending insect, or in the case of water treatment, germ, comes into contact with it.
Turton is an expert in the use of fluidized bed technology. That's why Worley came to him with the binding problem. In a fluidized bed, solid particles are made to behave somewhat like liquids when a gas is forced into a chamber.
In the experimental phase, the polymer carrier particles float on a high-pressure air stream through a narrow container and pass a sprayer, which will apply a binder and a very fine dust of Poly1. The binder, said Turton, may be something as simple as a soluble polymer solution or another solvent that would soften the plastic in such a way that the Poly1 will fuse to it. Or, perhaps, hot polymer would be extruded into the fluidized bed where it would come into contact with a Poly1 powder.
"I'm pretty sure it will work," he said. "Whatever way we find that will cause the Poly1 to stick to the carrier, the big question will be whether the biocidal Poly1 will stay attached, and if it does, has attaching it to the carrier diminished its effectiveness?"
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