Interesting stuff:

Natural disasters often leave survivors without access to safe drinking water. Now researchers have made a cheap, lightweight material that could help survivors get that water fast. It’s a porous gel embedded with silver nanoparticles that works like a bacteria-killing sponge (Environ. Sci. Technol. 2013, DOI: 10.1021/es401219s). The gel absorbs tainted water, kills bacteria in seconds, and releases drinkable water with just a squeeze.

http://cen.acs.org/articles/91/web/2013/08/Spongy-Material-Puts-Squeeze-Waterborne.html