Re: electrolysis


Farooq W wrote:
Ron Jones wrote:
Farooq W wrote:
tomm...@xxxxxxxxx wrote:
Do you know if there is a way to passively extract oxygen/hydrogen
molecules from the atmosphere?

Oxygen is commercially distilled from air-see liquefaction of air.
Also check the composition of Earth's atmosphere? Is hydrogen present
there?

There might be some technology to selectively absorb oxygen from air
on a solid/liquid and later desorb oxygen from the material by some
chemical or physical means...perhaps it is called molecular sieve
technology.

There certainaly is. People who require oxygen as an aid to breathe are
often given a machine that does just that. Will easily deliver 0-5 litres
of oxygen per minute. I beleive it's just a adsorption of oxygen with
pressure (and then desorption as pressure is removed)

But how is that made selective? If the material has affinity for O2
then surely nitrogen will also be adsorbed.


Why do you say "surely" nitrogen will be adsorbed? Hemoglobin, for
one, is a compound which selectively binds oxygen, and releases it when
oxygen partial pressure is reduced.

Metals selectively bind oxygen, because the nitrogen is so much less
reactive.

I don't know the details of the device Ron described, but I'm sure
there are numerous materials which meet the requirements of oxygen
selectivity.

Dave





--
Ron Jones
Process Safety & Development Specialist
Don't repeat history, see unreported near misses in chemical lab/plant
at http://www.crhf.org.uk
Only two things are certain: The universe and human stupidity; and I'm
not certain about the universe. ~ Albert Einstein

.

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