Sop story: new porous gel soaks up heavy metal.A team of chemists has created a new porous material that's extremely effective at sopping sop·ping
Thoroughly soaked; drenched.
Extremely; very: sopping wet.
completely soaked; wet through Also: ( up mercury. Called a chalcogenide aerogel aerogel, any of a group of extremely light and porous solid materials; the lightest is less than four times as dense as dry air. Aerogels are produced from certain gels (see colloid) by heating the gel under pressure, which causes the liquid in the gel to become or simply a chaleogel, the material could be used as a filter for cleaning contaminated drinking water drinking water
supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. . The material's versatility also makes it a good candidate for a wide range of other applications, including the production of hydrogen fuel.
Mercouri Kanatzidis of Northwestern University in Evanston, III., and his colleagues have created several chalcogels by, in each case, combining two ingredients. One ingredient is always a chalcogenide--a compound containing at least one of the elements sulfur, selenium selenium (səlē`nēəm), nonmetallic chemical element; symbol Se; at. no. 34; at. wt. 78.96; m.p. 217°C;; b.p. about 685°C;; sp. gr. 4.81 at 20°C;; valence −2, +4, or +6. , or tellurium tellurium (tĕlr`ēəm) [Lat.,=earth], semimetallic chemical element; symbol Te; at. no. 52; at. wt. 127.60; m.p. 450°C;; b.p. 990°C;; sp. gr. 6. , which lie directly below oxygen in the periodic table, and at least one positively charged element. The second ingredient includes platinum, which links the chalcogenide molecules.
In this case, the researchers combined a platinum compound with a chalcogenide containing sulfur and the semiconductor germanium germanium (jərmā`nēəm) [from Germany], semimetallic chemical element; symbol Ge; at. no. 32; at. wt. 72.59; m.p. 937.4°C;; b.p. 2,830°C;; sp. gr. 5.323 at 25°C;; valence +2 or +4. . After dissolving the two ingredients in water, the researchers poured the mixture onto a petri dish pe·tri dish
A shallow circular dish with a loose-fitting cover, used to culture bacteria or other microorganisms.
a shallow, circular, glass or disposable plastic dish used to grow bacteria on solid media such as agar. and let it sit for 2 days. The liquid turned into a dark-brown gel. Careful washing and drying preserved the gel's highly porous structure.
"It's very simple chemistry," says Stephanie Brock, a chemist at Wayne State University Wayne State University, at Detroit, Mich.; state supported; coeducational; established 1956 as a successor to Wayne Univ. (formed 1934 by a merger of five city colleges). in Detroit. "And that's one of the things that's very elegant about it."
To test the new material's ability to clean water, the team passed solutions highly contaminated with mercury through the chalcogel. Because mercury likes to bind to to contract; as, to bind one's self to a wife s>.
See also: Bind sulfur, explains Kanatzidis, the heavy metal accumulated on the surfaces of the numerous pores inside the material. In fact, the chalcogel removed up to 99.9 percent of the mercury in tainted solutions, the researchers report in the July 27 Science.
The team's initial findings indicate that the chalcogel performs just as well as, and sometimes even better than, commercially available water-filtration materials, says Kanatzidis. Unfortunately, the presence of platinum makes the new material too expensive to use in a commercial setting, he adds. His lab's next goal is to replace the platinum with a cheaper alternative.
Because the material also has interesting electronic and optical properties--due in part to the presence of germanium--such a chalcogel could be used for a range of applications beyond water remediation. Chalcogels can absorb both visible and infrared light, making them good candidates to act as light-triggered catalysts for a variety of reactions, including those that split water into hydrogen and oxygen.
Materials that use solar energy to produce hydrogen could one day generate the large amounts of hydrogen fuel needed to support a hydrogen economy (SN: 10/30/04, p. 282). That's one of many applications that Kanatzidis' group is interested in pursuing, he says.
"A lot of people are working on making hydrogen fuel," says Brock. "It's not a simple problem, and I don't think anyone has hit on a solution yet" The chalcogel, she says, could offer a new way forward.