'Dry' water, which resembles powdered sugar yet consists of 95 percent water, was discovered in 1968 and got attention in the cosmetics industry.   Each powder particle contains a water droplet surrounded by modified silica, which is much like ordinary beach sand. The silica coating prevents the water droplets from combining and turning back into a liquid so the result is a fine powder that can soak up liquids - or gases - which chemically combine with the water molecules to form a hydrate. 
 
Scientists 40 years later have begun to try and expand its range of potential applications - quite topically, they think it can soak up carbon dioxide and perhaps even be a greener, more energy-efficient way of jumpstarting the chemical reactions used to make hundreds of consumer products. Dry water also could provide a safer way to store and transport potentially harmful industrial materials. 

"There's nothing else quite like it," said Ben Carter, Ph.D at the University of Liverpool.   "Hopefully, we may see 'dry water' making waves in the future." 

One of the most recent involves using dry water as a storage material for gases, including carbon dioxide. In laboratory-scale research, researchers from University of Liverpool  found that dry water absorbed over three times as much carbon dioxide as ordinary, uncombined water and silica in the same space of time. This ability to absorb large amounts of carbon dioxide gas as a hydrate could make it useful in helping to reduce global warming, the scientists suggested. 

In previous studies, the Liverpool researchers learned that dry water is also useful for storing methane, a component of natural gas, and may help expand its use as a future energy source. In particular, they hope that engineers can use the powder to collect and transport stranded deposits of natural gas. This also exists on the ocean floor in the form of gas hydrates, a form of frozen methane also known as the "ice that burns." The powder could also provide a safer, more convenient way to store methane fuel for use in vehicles powered by natural gas. "A great deal of work remains to be done before we could reach that stage," Carter added.

In another potential new application, the scientists also showed that dry water is a promising means to speed up catalyzed reactions between hydrogen gas and maleic acid to produce succinic acid, a feedstock or raw material widely used to make drugs, food ingredients, and other consumer products. Manufacturers usually have to stir these substances together to get them to react. By developing dry water particles that contain maleic acid, Cooper and colleagues showed that they could speed up the acid's reaction with hydrogen without any stirring, resulting in a greener, more energy-efficient process.

"If you can remove the need to stir your reactions, then potentially you're making considerable energy savings," Carter said.

Another new application where dry water technology shows promise is for storing liquids, particularly emulsions. Emulsions are mixtures of two or more unblendable liquids, such as the oil and water mixture in mayonnaise. The scientists showed that they could transform a simple emulsion into a dry powder that is similar to dry water. The resulting powder could make it safer and easier for manufacturers to store and transport potentially harmful liquids. 

The researchers are seeking commercial or academic collaboration to further develop the dry water technology. The U.K. Engineering and Physical Sciences Research Council (EPSRC) and the Center for Materials Discovery provided funding and technical support for this study.