WASHINGTON, July 26 (Xinhua) -- A new type of highly porous gel that can soak up heavy metals may be useful for environmental cleanup, U.S. researchers reported Thursday.

The gel is a "molecular sieve" that can trap large metals present in a solution, said the research team in an article published in the latest issue of the journal Science.

Most of the porous, inorganic materials that have been used for molecular sieving have been oxides, which prefer to form bonds with small metal ions such as magnesium and zinc.

Santanu Bag at the Northwestern University and collaborators have prepared a series of aerogels, which are basically rigid foams that preferentially absorb heavy metals.

The gel material is a metal chalcogenide rather than an oxide, where sulfur or selenium takes the place of oxygen.

The authors placed the gel in a solution containing smaller metal ions and larger, highly toxic metal ions such as mercury. The aerogel removed almost all of the mercury from the solution and also a number of organic compounds.