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Some have likened them to honeycombs; others to unending teacups, each only a billionth of a metre wide. But when it came to naming them they just had to be called nanosponges.
The idea is that one could clamp them across a water source — whether it is a kitchen tap or the pipe taking water into a power station — and they would soak up the fluid, catching impurities in their myriad tiny cavities and letting water through only in its purest form.


Nanosponges were invented at the Los Alamos National Laboratory in the United States by DeQuan Li and Min Ma over a decade ago. Within a couple of years Bheki Mamba and Rui Krause, of the University of Johannesburg in South Africa, began researching the sponges. They could see the potential for their own continent.

Another potential problem comes from the nanosponges' super-efficiency. While removing unwanted organic matter they might remove minerals that are useful to human health, acknowledges Krause. "In a rural community it may be important to remove biological pollution, such as [the bacteria] E.coli, while leaving some of the beneficial trace minerals if we can."
"Whether or not this is a real problem is open to debate, since we do not get a significant amount of minerals from the water we drink, and the polymers can be modified to remove things of specific polarity and size," he says.
Then there are the general fears about the potential health and environmental consequences of nanomaterials.
"Without knowing the properties of nanosponges we are being cautious," says Jo Burgess, manager of South Africa's Water Research Commission, which funds nanotechnology for drinking water, wastewater and mine water treatment."
"Nanosponges may be wonder materials with only beneficial effects, or they may be another asbestos — an apparent wonder material that turned out to cause health problems. Or more likely they will be somewhere in between.

After the Horse has bolted !

Nanosponges: South Africa's high hopes for clean water - SciDev.Net