A book with pages made of paper coated with bacteria-killing nanoparticles could help stop the spread of waterborne diseases in some parts of the developing world.
eveloped by former McGill University student Theresa Dankovich, the low-cost and easily transportable book would meet water needs of a single person for four years.
Dankovich, who stumbled on the idea while studying material properties of paper, has recently tested the technology in Bangladesh. Previous tests conducted in South Africa, Ghana, Haiti and Kenya showed more than encouraging results.
"In Africa, we wanted to see if the filters would work on 'real water', not water purposely contaminated in the lab," Dankovich explained. "One day, while we were filtering lightly contaminated water from an irrigation canal, nearby workers directed us to a ditch next to an elementary school, where raw sewage had been dumped. We found millions of bacteria; it was a challenging sample.”
The pages of the book removed 99.9 of contaminants present in the water making it fit to be consumed by humans without health consequences.
The nanoparticles used in the paper are based on silver and copper, which have been long known to have the capabilities to kill bacteria and various viruses. However, before Dankovich, no one tried to integrate such nanoparticles into paper to filter water. Both silver and copper can be toxic for the human body but the researcher says that quantities that can possibly escape from the paper into the water would do much less harm than the bacteria and viruses it removes.
"Some silver and copper will leach from the nanoparticle-coated paper, but the amount lost into the water is within minimal values and well below Environmental Protection Agency and World Health Organization drinking water limits for metals," Dankovich said.
Each page of the ‘drinkable book’ can filter up to 100 litres of water. On both sides of each page is printed information about water safety in English and in the native tongue of the region where the technology is meant to be used.
Upon removing the page from the book, the filter is placed into a special frame through which the water is poured and filtered.
"Worldwide, many people use a 5-gallon bucket for many needs, so we are basing our approach on that type of container,” said Dankovich.
"Along with applications, our biggest current focus is to scale up, going from a lab bench experiment to a manufactured product. We have to go from 'cool chemistry' to something everyone can understand and use."
Dankovich is further developing the technology as a postdoctoral researcher at Carnegie Mellon University.
Drinkable Book infographic