‘Super sand’ to purify drinking water

June 23rd, 2011 - 4:08 pm ICT by IANS  

Bangalore, June 23 (IANS) Scientists have developed a way to chemically transform ordinary sand into so-called “super sand” for improved purification of drinking water.

Ordinary sand, an abundant natural resource of the earth, is a preferred filter material used throughout the world to purify drinking water from municipal water supplies to small domestic water filters, particularly as packed bed filters.

The new method transforms the regular sand into a “super sand” with five times the filtering capacity, according to a report in the journal Applied Materials & Interfaces published by the American Chemical Society (ACS).

The new material developed by Mainak Majumder and colleagues at Monash University in Australia “could be a low-cost boon for developing countries, where more than a billion people lack clean drinking water”, the ACS said in a statement.

Majumder and colleagues started off with a nanomaterial called graphite oxide and chemically modified its surface to enable its use as a novel material for low-cost water purification processes.

They used a simple method to coat sand grains with surface modified graphite oxide, creating super sand that successfully removed mercury and a dye molecule from water.

Its filtration “performance is comparable to some commercially available activated carbon”, the scientists said.

In other words, they have demonstrated a simple technique for conversion of regular filtration sand into “core-shell” graphite oxide coated sand granules that improved sand filtration in a cost-effective way.

“The nanostructured graphite oxide-coated sand retains at least five-fold higher concentration of heavy metal and organic dye than pure sand,” the scientists reported.

Thus suitably engineered graphite oxide, particularly derived from natural graphite, can improve existing processes and spawn low-cost water purification technologies suited for the developing economies, their report said.

The researchers said they are currently investigating strategies that will enable the assembly of “functionalised graphite oxide particles on the sand grains to further enhance contaminant removal efficiencies”.

(Killugudi Jayaraman can be contacted at killugudi@hotmail.com)

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