Researchers have also designed and synthesized ionic liquids that remove cadmium and mercury from water, which could be used to clean up industrial effluent. When ionic liquids come in contact with contaminated water, they snatch and sequester metal ions, according to James H. Davis, Jr., Ph.D., assistant professor in the department of chemistry at the University of Southern Alabama in Mobile. Davis developed the water purification technique with Robin D. Rogers, Ph.D., director of the Center for Green Manufacturing at the University of Alabama in Tuscaloosa. The Alabama researchers have also devised a way of using ionic liquids to remove impurities from natural gas. Unrefined natural gas contains many contaminants, particularly carbon dioxide and hydrogen sulfide.
Conventional techniques use organic solvents to remove contaminants.
During the purification process, however, the organic solvents can get caught up in the natural gas stream - in effect, exchanging one contaminant for another. The ionic liquid solvents that Davis designed and synthesized incorporate chemical groups that react with carbon dioxide and hydrogen sulfide, literally binding them into the solvent. Preliminary results indicate that heating contaminant-laden ionic liquids in a vacuum reverses the binding process, permitting the liquids to be reused, he says. Oxidation of organic compounds is one of the most fundamental reactions in chemistry. Such reactions create epoxides - biologically reactive chemicals that are widely used in making pharmaceuticals.