Producing clean water in an emergency
平特五不中 researchers develop a new and inexpensive way of filtering water using silver nanoparticles
Disasters such as floods, tsunamis, and earthquakes often result in the spread of diseases like gastroenteritis, giardiasis and even cholera because of an immediate shortage of clean drinking water. Now, chemistry researchers at 平特五不中 have taken a key step towards making a cheap, portable, paper-based filter coated with silver nanoparticles to be used in these emergency settings.
鈥淪ilver has been used to clean water for a very long time. The Greeks and Romans kept their water in silver jugs,鈥� says Prof. Derek Gray, from 平特五不中鈥檚 Department of Chemistry. But though silver is used to get rid of bacteria in a variety of settings, from bandages to antibacterial socks, no one has used it systematically to clean water before. 鈥淚t鈥檚 because it seems too simple,鈥� affirms Gray.
Prof. Gray鈥檚 team, which included graduate student Theresa Dankovich, coated thick (0.5mm) hand-sized sheets of an absorbent porous paper with silver nanoparticles and then poured live bacteria through it. 鈥淰iewed in an electron microscope, the paper looks as though there are silver polka dots all over,鈥� says Dankovich, 鈥渁nd the neat thing is that the silver nanoparticles stay on the paper even when the contaminated water goes through.鈥� The results were definitive. Even when the paper contains a small quantity of silver (5.9 mg of silver per dry gram of paper), the filter is able to kill nearly all the bacteria and produce water that meets the standards set by the American Environmental Protection Agency (EPA).
The filter is not envisaged as a routine water purification system, but as a way of providing rapid small-scale assistance in emergency settings. 鈥淚t works well in the lab,鈥� says Gray, 鈥渘ow we need to improve it and test it in the field.鈥�
The research was funded by the National Sciences and Engineering
Council of Canada (NSERC) and the work is part of the NSERC
Sentinel Bioactive Paper Network.
The team鈥檚 findings were recently published in the Journal of
Environmental Science & Technology. For an abstract of the
article, please visit:
For more information about Derek Gray鈥檚 lab: /pprc/members/gray/
Complete article available on request.