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

US Army's gravity-defying alum...
A render of the water-purifying aluminum panel
A render of the water-purifying aluminum panel
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A treated aluminum panel developed by US Army and University of Rochester researchers can purify water with sunlight
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A treated aluminum panel developed by US Army and University of Rochester researchers can purify water with sunlight
Through its testing, the team found that its panel could cut down typical contaminants like detergents, dyes, urine, heavy metals and glycerin to levels that made the water safe for drinking
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Through its testing, the team found that its panel could cut down typical contaminants like detergents, dyes, urine, heavy metals and glycerin to levels that made the water safe for drinking
A render of the water-purifying aluminum panel
3/3
A render of the water-purifying aluminum panel
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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

“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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10 comments
michael_dowling
The collection of the purified vapor is not described,which is kind of important.
Alien
Interesting...but how and where is the purified water collected? Obviously a key addition to army survival equipment, one could also imagine this becoming a standard accessory in lifeboats.
jerryd
They have has solar stills on lifeboats forever. I even had one from a WW2 aircraft over water survival kit with raft used as the pilot's seat cushion.
Kpar
Both michael and Alien brought up the questions it raised for me. Sounds great, but it would have been nice to show it- or at least describe it.
Johannes
Is aluminium the only substrate on which this functionality can be achieved?
windykites
No mention of quantities of water cleaned and rate. Also the video shows the water evaporating into the air. I have read that water can be purified (to some extent) by filling a plastic bottle and hanging it in sunlight.
Trylon
Collection of the condensate is a simple matter and doesn't need to be explained. That's the simple part of the process which requires no technological progress. They already have the body of water there that can absorb the heat from the vapor to condense it.
SendSauce
Nobody said it was a product. It's a technology demonstration and the water collection aspect is not going to be a showstopper. Cost of production will until the laser process can be done quicker and less expensively. Point is, the higher cost of initial production units is more than made up for by it's portability and efficiency. Think it though, it's an incredible proof-of-concept.
Worzel
''.......... it is very easy to clean by simply spraying it,”
With what??
The dirty water that is being cleaned, or the clean water that has just been obtained??
ljaques
Great proof of concept (wicking pic) and great CGI showing massive amounts of vapor. But no collection, no numbers showing how much any enclosure would diminish the effectiveness of the "still", no numbers saying what kind of water return the have per square meter, etc. One more dog & pony show, eh?