16-08-2012, 12:32 PM
Super sand
super sand.pptx (Size: 1.12 MB / Downloads: 51)
Production method.
Using nanotechnology, Rice University scientists coated grains of sand with a nanomaterial called graphite oxide (GO), a product in the chemical exfoliation process of graphite (aka pencil lead) that leads to single-atom sheets known as graphene via subsequent reduction. These nanosheets of carbon can be engineered to have either hydrophobic (water-hating) or hydrophilic (water-loving) properties, and when combined with sand, the coatings adhere to the grains and thus and exposure of the hydrophilic parts is ensured.
Coating the sand
the sand involves dispersing graphite oxide into water and mixing it with regular sand.
Then the whole mixture is heated up to 105C for a couple of hours to evaporate the water, and the final product i.e., “coated sand” is used to purify polluted water.
Cost-efficient
This can be synthesized using room temperature processes and also from cheap graphite sources, it is likely to be cost-efficient.
Coated sand does good job of filtering out dyes and heavy metals as activated carbon which are relatively expensive.
Effectiveness
This material demonstrates comparable performance to some commercially available activated carbon materials.
It was possible to modify the graphite oxide in order to make it more selective and sensitive to certain pollutants - such as organic contaminants or specific metals in dirty water.
By attaching different functional moieties onto graphite oxide, we could engineer some form of a ‘super sand’ to target specific contaminants species, like arsenic, trichloroethylene and others,
Advantages
Many mining companies extract graphite and they produce a lot of graphite-rich waste.This waste can be harnessed for water purification.
Concluding remarks
In the future, it could do an even better job at targeting dangerous particles: The next step for the super-sand creators is to create coatings that could specialize in capturing particular contaminants, like arsenic.
It has to be a national effort and everyone has to contribute.