US Army’s gravity-defying aluminum panel purifies water with sunlight

Providing clean drinking water in regions where the resource is scarce is a huge challenge, and one that we’re seeing plenty of inventive solutions to. A research team from the US Army and the University of Rochester is throwing a new possibility into the mix, showing off a “superwicking” aluminum panel that uses solar power to purify water with great efficiency.

Solar power has proven a popular choice when it comes to powering low-cost water purifiers, with sunlight long known to destroy waterborne pathogens. We have looked at quite a few technologies over the years that leverage this process to produce clean water through low-cost and portable platforms, but the researchers behind the latest system say it offers an entirely new level of efficiency.

The technology begins with a regular aluminum panel, which is treated with ultrashort femtosecond laser pulses to produce an open-grooved surface that is pitch black. This makes the material highly absorptive and “super-wicking,” enabling it to draw a thin film of water from a reservoir up over the metal’s surface, even against the forces of gravity.

While this is going on, the pitch black material gathers energy from the sun and is able to retain nearly all of it to heat up the water. The structures etched into wicking surface then alter the molecular bonds in the water, increasing the efficiency of the evaporation process that rids it of its contaminants.

A treated aluminum panel developed by US Army and University of Rochester researchers can purify water with sunlight
A treated aluminum panel developed by US Army and University of Rochester researchers can purify water with sunlight

University of Rochester

“These three things together enable the technology to operate better than an ideal device at 100 percent efficiency,” said Professor Chunlei Guo, professor of optics at University of Rochester. “This is a simple, durable, inexpensive way to address the global water crisis, especially in developing nations.”

Through its testing, the team found that the panel could cut down typical contaminants like detergents, dyes, urine, heavy metals and glycerin to levels that made the water safe for drinking. Additionally, the device offers easy cleaning after use, and can be reconfigured on-the-go for optimal efficiency.

“Moreover, because we use an open-grooved surface, it is very easy to clean by simply spraying it,” Guo says. “The biggest advantage 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.”

The research was published in the journal Nature Sustainability, while the video below provides an overview of the device.

Sustainable water purification using laser treated metal

Source: US Army, University of Rochester

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