Floating photocatalyst turns sunlight into radicals that disinfect water in minutes

Extremely light, floating films could make foul water fit to drink by using light to kill harmful bacteria. The film, comprising a photocatalyst that generates long-lasting bactericidal radicals, is quite potent under low light intensities and can purify water even under smartphone light.

Lack of access to safe drinking water claims up to 2 million lives annually, including a child under five every two minutes. This crisis is compounded by the fact that 81% of the at–risk population lives in low- and middle-income countries and remote villages that are plagued by poor infrastructure that often have no centralised water treatment plants.