A sponge-like material that can purify water has been developed by scientists in South Korea. Making water safe requires technologies that can remove almost any pollutant. This need is likely to increase as the worldÃ¢ÂÂs population grows and access to fresh water becomes scarcer. Nanomaterials offer one possible solution. Graphene-oxide membranes, for example, can absorb toxic organic solvents and other hazardous chemicals but further improvements..