Rice U. lab leads hunt for new zeolites( In all the world there are about 200...)

In all the world, there are about 200 types of zeolite, a compound of silicon, aluminum and oxygen that gives civilization such things as laundry detergent, kitty litter and gasoline. But thanks to computations by Rice University professor Michael Deem and his colleagues, it appears there are -- or could be -- more types of zeolites than once thought.

A lot more.

A project that goes back 20 years came to fruition earlier this year when Deem, Rice's John W. Cox Professor in Biochemical and Genetic Engineering and a professor of physics and astronomy, and his team came up with a list that shows the structures of more than 2.7 million zeolite-like materials.

Of those, they found the thermodynamic characteristics of as many as 314,000 are near enough to currently known zeolites that it should be possible to manufacture these materials.

Creation of the public database is the focus of a new paper, "Computational Discovery of New Zeolite-Like Materials," posted online by the American Chemical Society's Journal of Physical Chemistry C and planned as the cover of the Dec. 24 print edition. The paper's authors include Ramdas Pophale, a postdoctoral research associate in Deem's lab; Phillip Cheeseman, senior scientific applications analyst at Purdue's Rosen Center for Advanced Computing; and David Earl, an assistant professor of chemistry at the University of Pittsburgh.

Zeolites can be viewed as "a membrane that will only let molecules of a certain size pass through," Deem said. "But they also do other things. They have an affinity for some molecules, so they're used to absorb odors, for instance, in flower shops."

In laundry detergents, zeolites trade soft ions for hard ones in the water, and the petrochemical industry uses zeolites to crack petroleum into gasoline, diesel and other products. After the accident at the Three Mile Island nuclear power plant, zeolites were used to adsorb radioactive ions.'/>"/>