With much of the world still lacking access to safe drinking water, the need for more efficient filtration systems is higher than ever. Wei Gao, from Rice University in Texas, has however invented a graphite-coated type of sand that is cheap to produce and much more effective at filtering water.
He called it the “super sand.” Each and every grain of this sand is coated in an oxide of graphite – a material you’re surely acquainted with from pencils. He tells the BBC that regular coarse sand is a lot less effective than fine sand when the water is contaminated with pathogens, organic materials and heavy metal ions.
“This material demonstrates comparable performance to some commercially available activated carbon materials,” says Dr Mainak Majumder from Monash University in Melbourne, Australia. “But given that this can be synthesized using room temperature processes and also from cheap graphite sources, it is likely to be cost-efficient,” he adds.
Gao explains the technique they used to produce the super sand. She says it involves dispersing graphite oxide into water and mixing it with regular sand. “We then heat the whole mixture up to 105C for a couple of hours to evaporate the water, and use the final product – ‘coated sand’ – to purify polluted water.”
Cleaning water is a must for today’s technology to solve cheaply and energy efficiently, since the World Health Organization says that “just 60% of the population in Sub-Saharan African and 50% of the population in Oceania [islands in the tropical Pacific Ocean] use improved sources of drinking-water.”
[via goodcleantech]
I remember from my early geography studies that contaminated water that passed through the surface soil of a normal grassland/forest et al for a mile or so would be potable when it resurfaced.
This knowledge is encapsulated in a system used over here where we bias the effluent underground and let it anaerobically purify, or bias it to surface dams populated by lillies on top and a myriad of things underneath.
And yes it is potable, more so than the local council attempts where they take pure water and pollute it with purifiers.
Russ
VERY HAPPY TO SEE AN ECONOMICAL SOLUTION TO THE WATER PROBLEM.i ONLY WISH THIS IS MASS PRODUCED AND AFFORDABLE TO MILLIONS AROUND GLOBE WHO ARE WATER STARVED.WE IN PART OF CHENNAI IN SOUTH INDIA ARE FORCED TO GO FOR WATER TREATMENT PLANTS WHICH ARE COSTLY BUT A HEALTH NECESSITY , OTHER WISE YOU PAY THE DOCTOR.
hope some one comes up with a cheaper technology here also, which can save millions of hut dwellers and their children from stomach disorders and other water born diseases.