Access to clean water can be challenging in isolated areas
Kornienko Alexander/Alamy
A hand-cranked bottle could transform the availability of safe drinking water in areas affected by disasters and in off-grid communities.
Xudeng professors at the University of Electronic Science and Technology of China in Chengdu are committed to developing a straightforward approach to eliminate bacterial, viral, and fungal pathogens, as well as parasites from water.
“We often faced the same challenges in decentralized water treatment,” says Deng. “Most point-of-source (POS) solutions need electricity or ample sunlight and are labor-intensive.”
In areas without grid access and during emergencies when standard systems fail, an invention was required to disinfect water using a simple one-minute manual action.
Their method utilizes spherical silica nanoparticles coated with amine-based compounds that acquire a positive charge in water, along with gold nanoparticles that become negatively charged when agitated.
“Imagine a hand-cranked bottle filled with a small quantity of a synthetically made sand-like powder,” Deng explains. “A few turns of the handle induce a gentle shear in the water, activating the nanoparticles.”
As water flows over the gold and amine nanoparticles, it generates an electric charge that produces oxidizing agents known as reactive oxygen species.
“These reactive oxygen species puncture the membranes of microorganisms, rendering the pathogens incapable of survival or reproduction,” Deng states. “When agitation ceases, the powder naturally separates from the water, allowing clean water to flow out of the outlet.”
The research team evaluated the device against 16 highly infectious pathogens known to pose significant public health threats, achieving a reduction rate of 99.9999%. A similar level of reduction was noted for Escherichia coli in just 15 seconds of stirring at 50°C and for cholera bacteria in one minute. In total, it inactivated over 95 percent of all tested microorganisms.
Deng mentioned that the device is still in the proof-of-concept phase, so researchers haven’t yet established how many liters of water it can purify.
“What we do know is that after each cycle, the same set of particles can be collected and reused,” he adds. “Moreover, once charged, this system provides prolonged defense against recontamination for several hours.”
Since the quantity of gold nanoparticles used is minimal, their expense is negligible, with the primary cost attributed to the silica powder and plastic casing.
Chiara Neto from the University of Sydney in Australia expressed her admiration for the scientific advancement and novel applications of nanoparticles in disrupting pathogen cell membranes. “It’s a brilliant and impressive piece of work.”
Source: www.newscientist.com
