Rice U. lab leads hunt for new zeolites(p Zeolites are a fine lattice a molec...)

Zeolites are a fine lattice, a molecular sieve that can let molecules of a certain size pass while blocking others. They can also adsorb molecules, attracting and gripping certain substances -- for which cats and their owners are grateful.

Natural zeolites are often the product of volcanic activity, as rocks, ash and alkaline water combine and crystallize over thousands of years. "The term zeolite comes from the combination of two Greek words that mean 'boiling' and 'stone,'" Deem said.

About a third of zeolites used for commercial purposes are mined, while the rest are synthesized into custom configurations that tend to be more pure, he said.

The fact that only 200 or so zeolites are known makes the creation of Deem's database a real breakthrough, as it gives industries new clues to optimizing their techniques. "That's one possibility, to look for related materials," he said. "In many catalytic applications, there's only one material that currently works."

It took serious computer time to figure out all the possibilities, said Deem, who has lately gained a measure of fame for his study of viruses, particularly H1N1. He began looking at zeolites two decades ago while at Exxon and published his first paper on the subject in the journal Nature. With support from the National Science Foundation (NSF) and the use of the Deem lab's Zefsa II software, researchers needed three years to complete the computations on the NSF's TeraGrid node at Purdue. "I think we were the biggest user of computer time there in 2006, and the fifth- or sixth-largest on the TeraGrid," Deem said. "At Purdue, we were making use of unused computer cycles, like the SETI@home project that searches for extraterrestrial life using people's home computers. We finished around the start of 2009."

The "big question," he said, is how to turn theoretical zeolites into real ones, a project his lab plans to pursue. "A couple of things have to happen. One is
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