Graphite-coated sand could clean up dirty drinking water

BBC : Researchers have been working on a new technology to decontaminate water in developing countries. It involves coating grains of sand with an oxide of graphite, a widely available material commonly used as pencil lead. Sand has been used to purify water since ancient times. Although fine sand is more effective than coarse when cleaning water of pathogens, organic materials, and heavy metal ions, water drains much more slowly through fine sand than coarse. “Our product combines coarse sand with functional carbon material that could offer higher retention for those pollutants, and at the same time gives good throughput,” explained Wei Gao of Rice University, one of the authors of a study published in Applied Materials and Interfaces. In addition, lead scientist Pulickel Ajayan, also at Rice, said the graphite oxide could be modified to make it more selective and sensitive to certain pollutants. Because the necessary materials are cheap and readily available and the graphite-coated sand grains can be synthesized using room-temperature processes, the researchers say the method would be very cost efficient.