Biocidal paper for emergency water purification

This work was carried out as part of the NSERC Sentinel Bioactive Paper Network. The aim was to make a cheap, lightweight paper-based filter for emergency water purification, using biocidal action rather than simple filtration. In flood disaster areas, there is an overabundance of contaminated water but a shortage of clean drinking water. Our aim was to develop a light, cheap paper-based filter that could remove a significant amount of the most dangerous contaminants. As biocide, we focused on silver, in both ionic and nanoparticle forms. The aim was to generate a high concentration of biocide within the paper sheet structure, while minimizing the amount of metal ions released in the eluent. This was not envisaged as a routine water purification system, but as way to provide rapid small-scale assistance in emergency situations. We think it may be easier to store and transport paper filters than to deliver pure water to disaster areas.

Diagram showing biocidal paper

Basic idea (from Dankovich and Gray, Environmental Sci. Technol., 45(5), 1992-1998 (2011).)

The major challenge was to make sufficiently pure water in the time that a water sample percolates through the paper sheet. Initial results on a model suspension of e. coli showed promise, with a log 5 reduction in live bacteria passing through the AgNP sheet. (Environmental Sci. Technol., 45(5), 1992-1998 (2011) doi:10.1021/es103302t.)

Dr. Theresa Dankovich has continued this work, field-testing the concept in several tropical locations, and setting up a company, Folia Water, to develop the concept of the “Drinkable Book”.

Next: Chiral cellulose structures in plants