BUSINESSWEEK ONLINE : NOVEMBER 27, 2000 ISSUE
SCIENCE & TECHNOLOGY

From a Volcano to Your Washing Machine--and Beyond


Photo by JONATHAN CHAPMAN
Crystal Gazing Chemist Andreas Stein envisions oil-grabbing crystals that can clean up spills


Look at the ingredients listed on a box of laundry detergent, says Andreas Stein, a chemist at the University of Minnesota. ''You may find 'aluminosilicates as water softeners.' These are zeolites.'' The tiny porous crystals function as sponges for the calcium and magnesium atoms that make water ''hard.'' Recently, zeolites emerged as a hot area of so-called meso-scale research. This is the field of materials science that studies structures and processes involving things bigger than atoms and molecules but smaller than the clumps of bulk materials in traditional test tubes and vats.

CATALYSTS. Nature's zeolites, found in volcanic rocks, were first introduced to industry in the 1950s. Because they're even more porous than sponges, zeolites have an enormous surface area--hundreds of square meters per gram. And the aluminum atoms studding the cavern walls of the silicon dioxide-based crystals can serve as catalysts to trigger chemical reactions. Led by ExxonMobil Corp., the petrochemical industry has been refining oil with zeolite catalysts since the early 1960s. Today, most oil and many polymers are processed with zeolites, although the crystals are now largely man-made. Their pores are carefully tailored to admit molecules up to a certain size, but no bigger. Zeolites with slightly different pore sizes produce gasoline with different octane ratings by separating petroleum molecules of different sizes--larger molecules packing more energy.

What sparked the latest round of research was Mobil's development in 1992 of a new kind of zeolite crystal. By modifying the basic inorganic structure with organic molecules, Mobil stretched the pore openings and channels, enlarging them enough to admit even the ''bottom-of-the-barrel'' gunk that until then had defied processing with zeolites. But the bigger pore sizes also opened the door to other exciting applications, including pharmaceuticals. Researchers at several schools--including Pennsylvania State University, Georgia Institute of Technology, and the Universities of Rochester, Toronto, and Wisconsin--began exploring the potentials of inorganic-organic hybrids. Late last year, a team of chemists from Arizona State University and the University of Michigan announced a metal-organic ''framework'' that can be used at temperatures up to 300C--highly unusual for a structure containing organic components, so even more applications may arise.

Back in Minneapolis, one of Stein's pet projects is aimed at a variation of zeolite water softeners. He wants to create a meso sponge that sops up oil. Someday, when an oil spill washes ashore, the cleanup crew may sprinkle Stein's oil-grabbing crystals on the water to get rid of the oil below the surface while it collects the thick stuff floating on top.

By Otis Port in New York

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

BACK TO TOP
RELATED ITEMS
It's a Nano World

TABLE: Just Like Child's Play

The Ultimate Library

Rainbow's End

Mix and Meld

Atomic Skyscrapers

From a Volcano to Your Washing Machine--and Beyond



INTERACT
E-Mail to Business Week Online

 
Copyright 2000-2009, Bloomberg L.P.
Terms of Use   Privacy Notice