Drinking water contaminated with bacteria has led to the death of millions of people around the world over the years, with young children proving to be the most at risk among all age groups. While water purification plants have been established in different countries, the cost of operating one facility is too expensive, especially for less developed countries to maintain.
This is what inspired Carnegie Mellon University researcher Dr. Theresa Dankovich to develop a water purifying system based on nanotechnology that is both inexpensive to create and easily transportable.
The new technology, which Dankovich calls The Drinkable Book, is made up of thick filter pages that are impregnated with metal particles that can effectively kill bacteria. It is based on the concept of silver and other such metals being able to eliminate microorganisms.
Dankovich discovered that by embedding silver particles on thick sheets of paper, she can purify water of bacteria and some forms of viruses. She then expanded her technology by incorporating other nanoparticles such as inexpensive copper.
To test the effectiveness of her newly-developed water purifying system, Dankovich conducted field investigations Limpopo, South Africa. She also carried out tests in areas in Kenya, Haiti and northern Ghana.
Dankovich said that she wanted to find out the application of the water purifying system on "real water" and not with water contaminated purposely for the experiment. While trying to purify lightly contaminated water samples collected from a local irrigation canal, Dankovich and her team were directed to a sewage dump by nearby workers. The amount of bacteria found in the ditch posed a challenging feat for the new water cleaning system.
Despite the millions of bacteria in the water source, the nanoparticle-embedded filter sheets were able to purify the water by as much as 99.9 percent. The copper and silver nanoparticles were able to bring the levels of bacteria in the water sample comparable to those of drinking water found in the United States.
Dankovich explained that while some of the copper and silver nanoparticles will remain leached on the filter paper, small amounts will be lost in the water sample during purification. She said that these lost nanoparticles are within the limits of metals in drinking water established by the World Health Organization (WHO) and the Environmental Protection Agency (EPA).
Dankovich is set to present her The Drinkable Book as well as the findings of her field tests on the water purifying technology at the American Chemical Society's (ACS) 250th National Meeting & Exposition.
Photo: Jeff Turner | Flickr