chalcogenides.com

Inorganic porous materials are being developed for use as molecular sieves, ion exchangers, and catalysts, but most are oxides. We show that various sulfide and selenide clusters, when bound to metal ions, yield gels having porous frameworks. These gels are transformed to aerogels after supercritical drying with carbon dioxide. The aerogels have high internal surface area (up to 327 square meters per gram) and broad pore size distribution, depending on the precursors used. The pores of these sulfide and selenide materials preferentially absorb heavy metals. These materials have narrow energy gaps (between 0.2 and 2.0 electron volts) and low densities, and they may be useful in optoelectronics, as photocatalysts, or in the removal of heavy metals from water.

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http://www.sciencemag.org/cgi/content/full/317/5837/490}

By Julie Steenhuysen

CHICAGO (Reuters) - A new porous material can soak up heavy metals from liquids like a sponge, U.S. researchers said on Thursday, offering a host of potential uses including removing pollutants such as mercury or lead from water.

The material is an aerogel, a type of rigid foam made from a gel in which most of the liquid has been replaced by gas.

"What we've made is a new kind of aerogel that is made of the same stuff that semiconductors are made of," said Mercouri Kanatzidis, a researcher with Northwestern University in Evanston, Illinois, and the U.S. Department of Energy's Argonne National Laboratory.

Classical aerogels -- which are made of silica or carbon -- have been around for many decades. "They are white and colorless and don't absorb any light," Kanatzidis said in a telephone interview.

Kanatzidis has made aerogels from chalcogenides, which are used in semiconductors.

"These new aerogels absorb light and they can be changed in composition from one kind to another," said Kanatzidis, whose work appears in the journal Science.

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http://www.reuters.com/article/scienceNews/idUSN2618995520070726