Squeeze The Bacteria Out Of Water WIth A New Gel

[** Serge **]

In an emergency, clean drinking water can be tough to find. Floods, earthquakes and hurricanes can make our usual sources of water potentially unsafe.


After the 2004 tsunami in the Indian Ocean left many without access to clean water, researchers from Nanyang Technological University in Singapore and the University of Colorado, Boulder decided to create a water purification system that could kill bacteria quickly without requiring a power source. They came up with a bacteria-killing, spongy polymer gel that absorbs water, then releases it in a purified form when squeezed.

This could potentially be a super fast, convenient way to ensure access to clean water. Boiling contaminated water gets rid of nasty parasites like Giardia, but after a natural disaster, not everyone has the ability to boil all the water they need. Nor does everyone want to squeeze potable water from their own sweat.

A 4-gram cylinder of the gel can purify half a liter of water per squeeze, and can be reused more than 20 times without losing its ability to disinfect. Xiao Hu, one of the material's creators, estimates that a pocket-sized version of the gel for one person to use would cost about 50 cents to make, and could be dropped from helicopters by emergency aid workers after natural disasters. The researchers plan to field test their gel on water in Myanmar sometime in the near future.

http://www.popsci.com/science/article/2013-08/squeeze-bacteria-out-water-gel?src=SOC&dom=fb

http://pubs.acs.org/doi/abs/10.1021/es401219s?journalCode=esthag

[guillaume]

Merci Serge pour l'info !

Si je comprends bien, cela n'agirait que sur les bactéries. Ce qui semble normal puisque semble "capter" les bactéries dans la porosité du matériaux, un peu comme le charbon actif.

En revanche, le produit a une durée limité (adsorption maximale) mais il n'est pas fait mention d'un quelconque dispositif permettant de savoir quand on est au bout.

a+

[You]

"Abstract

This paper reports the preparation of poly(sodium acrylate) (PSA) cryogels decorated with silver nanoparticles (AgNPs) for point-of-use (POU) water disinfection. The PSA/Ag cryogels combine the high porosity, excellent mechanical and water absorption properties of cryogels, and uniform dispersion of fine AgNPs on the cryogel pore surface for rapid disinfection with minimal Ag release (<100 μg L–1). They were used in a process that employed their ability to absorb water, which subsequently could be released via application of mild pressure. Their antibacterial performance was evaluated based on the disinfection efficacies of E. coli and B. subtilis. The PSA/Ag cryogels had excellent disinfection efficacies showing close to a 3 log reduction of viable bacteria after a brief 15 s contact time. They were highly reusable as there was no significant difference in the disinfection efficacies over five cycles of operation. The biocidal action of the PSA/Ag cryogels is believed to be dominated by surface-controlled mechanisms that are dependent on direct contact of the interface of PSA/Ag cryogels with the bacterial cells. The PSA/Ag cryogels are thought to offer a simpler approach for drinking water disinfection in disaster relief applications."

Pour résumer : principe d'une éponge avec des nanoparticules d'argent.
Intéressant en post-filtration, reste à affiner la techno et attendre les premiers développements industriels.