A team of scientists led by László Forró at Ecole Polytechnique Fédérale de Lausanne have built a new drinking water purification filter, powered entirely by sunlight, by combining titanium dioxide (TiO2) nanowires and carbon nanotubes.
The TiO2 nanowires by themselves can efficiently purify water in the presence of sunlight — but interweaving the nanowires with carbon nanotubes forms a composite material, which adds an extra layer of decontamination by pasteurizing the water.
The idea is that when UV light hits the filter, it causes it to produce a group of molecules called Reactive Oxygen Species (ROS). These include hydrogen peroxide (H2O2), hydroxide (OH), and oxygen (O2-), and are known to be effective pathogen killers.
The researchers tested their device with E. Coli, but they say that it should also work with other bacteria pathogens, such as Campylobacter Jejuni (a common diarrhea-inducing pathogen in the developed world), Giardia Lamblia (a microorganism that causes the intestinal infection giardiasis), Salmonella, Cryptosporidium (causes diarrheal cryptosporidiosis), the Hepatitis A virus, and Legionella Pneumophila (causes Legionnaires' disease).