Researchers have developed a specialized aluminum panel that can purify contaminated water when angled at the sun.
The material, described in a study published in the journal Nature Sustainability, could prove useful in developing countries during water shortages or for water desalinization projects.
Its development was funded by the Army Research Office, with military officials hoping that the technology could also provide clean water to soldiers in the field.
The panel consists of regular aluminum that the researchers processed using specially developed laser technology to turn the material pitch black, while also making it super-wicking—meaning it effectively draws water uphill against gravity.
The aluminum panel is designed to be placed in dirty water while facing towards the sun. When deployed like this, the material draws a thin film of water upwards over the surface of the metal.
The pitch-black surface, which retains nearly 100 percent of the energy it absorbs from the sun, rapidly heats the water, causing it to evaporate.
According to the researchers, the evaporation rates they measured exceed that of an ideal device operating at 100 percent efficiency. Once the water has evaporated, it can then be collected. To do this, the scientists used a transparent and cleaned container, where the vapor condensates.
The team's experiments showed that the panel purified dirty water, reducing the level of contaminants to well below the standards for drinkable water set by the World Health Organization and the Environmental Protection Agency.
Specifically, the device significantly reduced levels of contaminants such as detergent, dyes, urine, heavy metals and glycerin.
Boiling water using the sun's heat effectively eliminates microbial pathogens, such as bacteria. However, it does not totally remove heavy metals and some other contaminants. Nevertheless, it does separate sufficient quantities from the water to ensure that it is safe to drink.
"This is a simple, durable, inexpensive way to address the global water crisis, especially in developing nations," Chunlei Guo, lead author of the study from the University of Rochester, said in a statement.
The researchers say that their device provides advantages over other similar approaches, in which floating, absorbing and wicking materials are placed on top of water in order to heat its surface. But because the materials have to float horizontally, they cannot face the sun directly.
"The biggest advantage [of our device] is that the angle of the panels can be continuously adjusted to directly face the sun as it rises and then moves across the sky before setting—maximizing energy absorption," Guo said.
"The technology can be used for either water sanitization or desalinization. Therefore, it can help generate potable water in both developing and developed countries where fresh water is in limited supply," Guo told Newsweek. "On a smaller scale, our system can be used as a survival kit for personal use. On a larger scale, the technology can be integrated into commercial solar-thermal systems to generate a large amount of clean water for a community."
This article was updated to include additional comments from Chunlei Guo.
