Sunday, August 21, 2016

Graphene based sheets for water filtration take two

See previous post on water purification

I can't find any of the graphene foam sheets for sale, but NewAtlas has an article on what they are and how they work.

The biofilm is created as a two-layered structure consisting of two nanocellulose layers produced by bacteria. The lower layer contains pristine cellulose, while the top layer also contains graphene oxide, which absorbs sunlight and produces heat. The system works by drawing up water from underneath like a sponge where it then evaporates in the topmost layer, leaving behind any suspended particulates or salts. Fresh water then condenses on the top, where it can be drawn off and used.
it doesn't require pipes, and it uses solar power.
more HERE.
full article for later reading HERE 

The advantage over old fashioned water filters is explained in the StrategyPage Article:

Together, this material when placed on the surface of polluted water uses sunlight and a sponge-like process to purify the water that can then be directed (by gravity) to containers. Field tests have shown that it works and the next step is to mass produce the graphene-based biofoam sheets and distribute them widely so regional variations in water and climate can be tested and tweaks made to the composition of the sheets for different conditions. 

alas, it doesn't look like it is commercially available, although graphene is being used in water filters and in all sorts of other things.

Guess I'll have to read up on it.

although for those of us in the third world, unless it is cheap and easy to find (i.e. the Chinese sell it cheaply) we will have to stick with old fashioned ceramic pot water filters.

also for later reading: Low cost water purifiers for the developing world.

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