Cancer-causing chemicals and drugs like antibiotics pollute many of America’s lakes, rivers and drinking water supplies. Activated carbon filters can remove about 40 percent of carcinogens and antibiotics from these waters. But a tiny solar-powered filter made of two bacterial proteins absorbs more than 50 percent more of the pollutants.
Antibiotics and chemicals enter waterways through sewage and run-off from yards and farms. They can breed resistant bacteria and kill helpful microorganisms, degrading the health of aquatic ecosystems.
The nano-filters, each smaller than the diameter of a human hair, employ a protein used by drug-resistant bacteria to excrete waste, but the researchers have turned it around so it sucks compounds in. Another protein, which responds to sunlight, provides the pumping power for the filter.
Environmental engineer David Wendell, one of the developers, calls the innovation an environmentally friendly and cost-effective way to extract and recover antibiotics from surface waters. He foresees the possibility that, one day, a collection of nano-filters could be anchored downstream from urban or farming areas to capture harmful compounds in water.
Details of the development and testing of the new filter appear in the journal Nano Letters.