A cartoon illustrates the potential uses of a new theoretical type of mobile technology that would use an aluminum alloy to convert non-potable water into drinking water while also extracting hydrogen to generate electricity. Such a lightweight, portable system might be used to provide power and drinking water to villages and also for military operations. Image: Jerry Woodall, Purdue Univ. |
Researchers have developed an aluminum alloy that could be
used in a new type of mobile technology to convert non-potable water into
drinking water while also extracting hydrogen to generate electricity.
Such a technology might be used to provide power and
drinking water to villages and also for military operations, said Jerry Woodall,
a Purdue Univ. distinguished professor of electrical and computer engineering.
The alloy contains aluminum, gallium, indium, and tin.
Immersing the alloy in freshwater or saltwater causes a spontaneous reaction,
splitting the water into hydrogen and oxygen molecules. The hydrogen could then
be fed to a fuel cell to generate electricity, producing water in the form of
steam as a byproduct, he said.
“The steam would kill any bacteria contained in the
water, and then it would condense to purified water,” Woodall said.
“So, you are converting undrinkable water to drinking water.”
Because the technology works with saltwater, it might have
marine applications, such as powering boats and robotic underwater vehicles.
The technology also might be used to desalinate water, said Woodall, who is
working with doctoral student Go Choi.
A patent on the design is pending.
Woodall envisions a new portable technology for regions
that aren’t connected to a power grid, such as villages in Africa
and other remote areas.
“There is a big need for this sort of technology in
places lacking connectivity to a power grid and where potable water is in short
supply,” he said. “Because aluminum is a low-cost, non-hazardous
metal that is the third-most abundant metal on Earth, this technology promises
to enable a global-scale potable water and power technology, especially for
off-grid and remote locations.”
The potable water could be produced for about $1 per
gallon, and electricity could be generated for about 35 cents per kilowatt hour
of energy.
“There is no other technology to compare it against,
economically, but it’s obvious that 34 cents per kilowatt hour is cheap
compared to building a power plant and installing power lines, especially in
remote areas,” Woodall said.
The unit, including the alloy, the reactor and fuel cell
might weigh less than 100 lbs.
“You could drop the alloy, a small reaction vessel
and a fuel cell into a remote area via parachute,” Woodall said.
“Then the reactor could be assembled along with the fuel cell. The
polluted water or the seawater would be added to the reactor and the reaction
converts the aluminum and water into aluminum hydroxide, heat and hydrogen gas
on demand.”
The aluminum hydroxide waste is non-toxic and could be
disposed of in a landfill.
The researchers have a design but haven’t built a
prototype.
