Access to clean water may be difficult in remote areas
Kornienko Alexander/Alami
A simple jar with a curved handle could revolutionize the provision of clean drinking water to disaster areas and remote communities without electricity.
Xu Deng from the University of Electronic Science and Technology of China in Chengdu says he and his colleagues were determined to create a simple way to rid water of parasites, as well as bacterial, viral and fungal pathogens.
“We kept hitting the same roadblock with decentralized water treatment,” Dan says. “Most point-of-use options require either electricity or strong sunlight and are slow.”
In off-grid communities and disaster areas, traditional systems are unreliable, so they needed an invention that could completely disinfect water with a minute of gentle hand stirring.
Their solution is based on spherical silica nanoparticles coated with amino group chemicals that become positively charged in water, and gold nanoparticles that become negatively charged in stirred water.
“Imagine a jar containing a small dose of a specially formulated sand-like powder,” says Dan. “A few turns of the handle create a slight shift in the water, and this movement ‘awakens’ our nanoparticles.”
The flow of water on the surface of the gold and amine nanoparticles creates an electrical charge, which in turn leads to the formation of oxidizing chemicals called reactive oxygen species.
“These reactive oxygen species punch holes in microbial membranes so pathogens cannot survive or reproduce,” says Dan. “When you stop stirring, the powder will separate from the water on its own and you will get clean water from the outlet.”
The team tested the device on 16 highly infectious pathogens that pose a serious threat to public health. A reduction of 99.9999 percent was achieved. coli in just 15 seconds of stirring water at 50°C and the same reduction Vibrio cholerae within 1 minute. Overall, it inactivated more than 95 percent of all microorganisms tested.
According to Deng, the device is still in the proof-of-concept stage, so researchers have not yet determined how many liters of water can be disinfected.
“We can say that the same batch of particles is recovered after each cycle and reused,” he says. “And once charged, the system provides long-lasting protection against recontamination for many hours.”
Because the amount of gold nanoparticles is so small, their cost is negligible—material costs are dominated by silica powder and plastic casing, he said.
Chiara Neto from the University of Sydney, Australia, says she is extremely impressed by the science and the new application of nanoparticles to disrupt the cell membranes of pathogens. “It’s very smart, fantastic work.”
