Indian water purification goes nano

Researchers at the Atomic Research Centre in Mumbai, India, said carbon nanotubes have several advantages over traditional purification systems like polycarbonate in that they’re simple and inexpensive to install, operate and maintain.

Carbon nanotubes are characterized by having smooth, water-repellent interiors. This means that a nano-designed filter could potentially have a high efficiency and flow rate because of this low resistance, according to the researchers who recently reported their findings in the International Journal of Nuclear Desalination.

Nanotube membranes have fascinated researchers with their combination of high flow rates and high selectivity. Carbon nanotubes have the advantage that only water molecules can pass along their interior while viruses, bacteria, toxic metal ions and other organic molecules are kept out, according to nanotech researchers.

Nanotech filtration systems have to be designed for processing contaminated water need to allow for the efficient decontamination and flow of water.

The Indian research team is currently investigating how water filtration systems based on carbon nanotubes could be used to remove arsenic, fluoride, heavy metals and toxic organic chemicals (see Nanotech starting to gel).

Water shortages and lack of access to safe drinking water is a big problem in India, as well as other countries.

Today, 1 billion people lack access to safe drinking water, according to the United Nations. A third of the world's population lives in water-stressed countries, and by 2025, this is expected to increase to two-thirds.

Water problems are particularly acute in developing countries where little, if any, water treatment or distribution infrastructure is available (see Cleantech water deals diving into rough market).

Many water filtration technologies available today have significant drawbacks, such as high pressure requirements, high electricity demands and the use of harmful chemicals.

Over the next five-to-10 years membrane technology will increasingly be used to purify water in individual homes as way to avoid large investments in water pipe infrastructure, according to water experts.

Estimates for the market for nanotechnology in water vary widely. But industry analyst Helmut Kaiser based in Germany predicts that applications of nanotechnology products in water and wastewater worldwide will reach $1.6 billion in 2007 and $6.6 billion in 2015, with over 43 percent focused upon filtration products.