Sand has been used as a purifier for thousands of years. An innovative way of cleaning water, by adding graphite waste, provides a cost affective way to bring purified water to those who may not normally have access to a clean water source. Via Treehugger:
The solution is cheap since the sources of graphite could include the waste produced by graphite mining companies that still contains a significant amount of graphite. And the researchers believe that it is possible to modify the graphite oxide to pick out particular pollutants and therefore tailor the super sand to specific areas that might be having trouble with certain water-borne diseases or pollutants.