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A team led by an IIT-Madras professor has devised a cheap and effective method to produce clean drinking water reports The Hindu.

It will soon be possible to produce 10 litres of water — free of bacteria and virus — at just Rs. 10-12 per month, for the daily consumption of a family of five.

Prof. T. Pradeep of the department of chemistry at IIT-M and his team have made use of silver nanoparticles to achieve this feat.

Apart from being affordable, silver nanoparticles coated on a composite do not require electricity or hydrostatic pressure to produce potable water.

They can operate at ambient temperatures ranging from 5-35 degrees Celsius, according to a paper published on May 7 in Proceedings of the National Academy of Sciences. The production of the nanoparticle matrix is also environment-friendly.

The technology is based on sustained release of about 50 parts per billion (ppb) of silver ions in a large volume of water to kill microorganisms. The amount of silver ions released is well below the maximum permissible limit of 100 ppb.

 “The consumer can use the filter for a year before reactivating it. It can be run for six cycles (six years),” Prof. Pradeep said. The use of carbon filter at a second stage helps in removing particulate matter, organic and bacterial biomass and traces of silver ions. Trials showed that composites made of specific materials were capable of removing contaminants like iron, lead and arsenic.

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