New aerogel is sponge for some toxins
Scientists say the porous material that can soak up heavy metals also shows promise in producing hydrogen-based fuels.
By Amber Dance, Times Staff Writer
July 28, 2007


Scientists have developed a lightweight, foamy material that can suck up toxic heavy metals like a sponge, according to a study published Friday.

The porous material, known as an aerogel, is made of sulfur or selenium instead of the traditional oxides.

The substance has so many pores and ridges that just 1 cubic centimeter has a surface size equivalent to a football field's.

In the study, published in the journal Science, the substance decontaminated a solution of 645 parts per million mercury down to 0.04 parts per million. It also effectively sponged up cadmium and lead.

"Nobody's ever demonstrated this absorption tendency for heavy metals from solution," said chemist Stephanie Brock of Wayne State University in Detroit, who was not involved in the study.

Mercouri Kanatzidis, the study's senior author, said: "It's as good as or better than the best materials out there."

Traditional aerogels look like frozen smoke and are used for air and water filters, for insulation and even to collect comet particles in NASA's Stardust mission.

The scientists first make a substance like gelatin, then carefully dry it out to yield a brittle, foamy material.

The new aerogel contains platinum, making it too expensive for cleanup efforts, but the method is likely to work with other less costly materials.

Kanatzidis, a chemist at Northwestern University, has other applications in mind. Because of the platinum, which speeds up production of hydrogen, Kanatzidis thinks the aerogel might be useful for production of hydrogen-based fuels.

The new aerogels are dark reddish-brown or black, which enables them to absorb light, so they could also be used in solar energy capture.