Driven by the unfortunate effects of the forces of nature, a team of researchers at the University of Texas has recently finished a prototype for a water purifier the size of a cup. This small cup has shown promising results that filter creek water and similar sources, making it potable.
The water-purifying cup prototypes were 3D-printed with electrode branches inside. These electrode branches are made of graphite foam.
When electrified, the E. coli cells present in the sample are attracted to the electrode branches, as if they simply voluntarily swim towards them. After that, the water becomes potable.
Aside from being efficient, the water-purifying cups are also cost-effective as one unit only costs $1.47 to make.
In their recently published study, a research team showed that in about 20 minutes, 99.997% of E. coli have been removed from two- to three-ounce (60 to 90 mL) samples using their water-purifying cup.
They got their samples from Waller Creek in Austin and tested the device at a few voltages and low energy consumption at 435.5 J/L. After some tests, the team said that one device can operate at least 20 times for more than 8 hours before seeing functional degradation.
While there are already various water treatment options to product potable water, researchers and experts are still on their quest to make a more convenient and portable solution. That is because looking at the current methods, there are some flaws that still need to be addressed.
For example, disinfecting pills can contaminate water with oxidants that can be harmful to the health. Reverse osmosis (RO) systems, which have already gained popularity over the past decades, are efficient, but require the use of high pressure pumps (therefore, high energy consumption). And solar steam generators are not exactly for everyday use as it becomes unreliable in the event of natural disasters — the inspiration of Fan’s research in the first place.
On the other hand, the use of electrical power, like in the team’s water-purifying cup, opens the potential for integration with batteries for stored energy. This then makes it more portable, so consumers can use it wherever they are. It also consumes much less energy than existing technologies.
Associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering Donglei Emma Fan talked about how it is possible to use such small amount energy.
“We are able to clean water using very little energy because we steer the bacterial cells with electric fields, and most bacterial cells are natural swimmers who propel themselves to electrodes and got captured alive,” Fan said.
Now, the researchers are aiming to commercialize their device by first simplifying the process of inserting and removing the electrodes.
“When our water infrastructure is down — no water, no gas and no electricity — we need point-of-use devices for cleaning water we can get out of ponds, streams or rivers,” Fan said. “We believe our device can someday fill that need.”
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