A new water filter that employs cotton dipped in nano-sized silver wires and copper tubes works 80,000 times faster than filters that simply block bacteria from getting through. The filter, developed by Stanford University researchers for use in developing countries, efficiently conducts a tiny charge of electricity, zapping 98 percent of all bacteria.
Millions of people die in rural and undeveloped areas every year from exposure to contaminated drinking water. The challenge is to create processes that work cheaply and reliably and uses materials that are light enough to transport. The pass-through filter is less likely to fail due to clogging or becoming infested with the bacteria it’s intended to kill: if bacteria cling to it, the silver kills them. And because its nano-materials are especially efficient conductors of electricity, the filter can get the jolt it needs from a small solar panel, a hand crank or 12-volt car batteries.
Unfortunately, when it comes to drinking water, 98 percent isn’t an adequate kill rate, so water would have to be filtered more than once. But since the filter works 80,000 times faster, there’s plenty of time for that.
Lead photo © Yi Cui