This inexpensive cup zaps pathogens to purify poor-quality water
While “don’t mess with Texas” may have originated as a littering campaign catchphrase, scientists from the southern state have aimed that mantra at waterborne bacteria, creating a powered drinking cup that kills pathogens that cross its energy-efficient electric field.
“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,” said lead author Donglei (Emma) Fan, an associate professor in the Department of Mechanical Engineering at the University of Texas at Austin.
The branched graphite-foam electrode model, inspired by a tree root system, creates an electric field that inflicts fatal cellular damage on E. coli. In lab studies, the device removed 99.97% of E. coli in 20 minutes. The water sample from Austin’s Waller Creek was small – two to three ounces – but the researchers believe the device is scalable with the potential to handle much more.
The foam-encased electrode can work continuously for hours and costs around US$2 to make. It’s also simple to use: fill, zap, wait and pour water into vessel for drinking.
Engineers envisage the electric field to be powered by battery, allowing for water to be sourced remotely or at home in the case of emergencies such as natural disasters – an area Fan has pivoted her research towards. While this lab model was just a 3D-printed prototype, they're working on tweaking the design for commercial purposes.
“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.”
The research was published in the journal ACS Nano.
For more on this study, see the video below.
Source: University of Texas at Austin