Chennai: Various studies suggest that nearly 15 states in India are endemic to fluorosis due to consumption of groundwater containing high fluoride concentration.

While the problem of heavy metal contamination in water is universal, the cost of purifying such water has been expensive.

Now, a Switzerland-based Indian scientist has designed a low-cost membrane from nano-sized protein fibrils to pull heavy metals and radioactive compounds out of water. The membrane filter can be simply placed above a container to collect purified water by pouring the impure liquid.

Scientist Sreenath Bolisetty working for ETH Zurich said the cost-effective filtering technology can remove close to 99 per cent of heavy metal pollutants like lead and mercury, certain bacteria and radioactive wastes like Uranyl acetate. It filters pollutant particles and brings down the concentration to 0.02parts per million, he said.

Bolisetty presented his patented technology in an international conference on water held in the city last week. He is a native of Nalgonda district, a fluorosis endemic district in Andhra Pradesh. "Popular filtering technologies like reverse osmosis and dialysis require big plants. But the filter I have developed is smaller than even the water purifier we use at home," he said.

The membrane is made from a composite of amyloid protein fibrous, a protein similar to those implicated in Alzheimer's disease, and activated porous carbon.

The fibre is made by processing whey protein, a byproduct of cheese production. "With 1kg of whey protein, about 64,000 litres of water can be filtered."

Bolisetty said the membrane filter is supported with a plastic frame and can be placed on a container to collect purified water. The scientist, who worked for more than two years to develop the technology, tested the filter with heavy metals like lead, mercury, gold and palladium.

Interestingly, the scientist found the membrane could trap gold. This, the scientist said, makes it possible for the filter to be used in gold mines.

Companies in the US, Canada, Africa, Germany, Switzerland and Austria have shown interest in trying the technology, he said.



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