separating oxygen and hydrogen from water

[pinobot]

Bit of an off-spin from the osmosis idea.
Would it be possible to separate water into oxygen and hydrogen by pressing it to a filter and how much pressure would be needed? Can't find anything on the net but maybe someone here knows?
To clarify the idea: a hydrogen atom is about 1/4 the diameter of an oxygen atom, so if you'd push the water hard into a filter that's just big enough to let the hydrogen atom through you'd separate water into oxygen and hydrogen (i think).

[Flit]

If you had loose oxygen and hydrogen atoms this may work.  Remember that water is made up of hydrogen and oxygen atoms that are bonded together so you would need to break that bond first before you could filter out the hydrogen.

Have you ever read Kym Stanley Robinson's Red Mars series?  He proposed a similar type of filter used to aid breathing based on the concept that oxygen is smaller than carbon dioxide so you could filter it out to allow the breathing of a hostile environment.

[pinobot]

I haven't read this perticular paper but it's seems to be a common way to separate gasses.
What i want is to brake the bond by fysical force pressing it through a filter, how much pressure would be needed (100 bar, 1k bar, 1m bar)?

[Flit]

Here is some information on bond energies in water.

http://www.chem.ox.ac.uk/vrchemistry/energy/Page_27.htm

I think that electrolysis would probably be more efficient and a lot cheaper than pressure seperation.  Working with high pressures is also very dangerous much like working with explosives.

Electrolysis, in its most basic form, requires nothing more than some wire a power source and some water.

Pressure seperation would require a vessel capable of containing high pressure, some sort of pump to produce the pressure and you would need a filter so small it is capable of letting through a hydrogen atom but denying an oxygen atom.  A filter of this type would, I imagine, be incredibly expensive.

It's an interesting concept though and it never hurts to think about new things.

[raburgeson]

What happens when the Oxygen clogs the filter?