O2 from water

dutchgold

Electrolysis allows o2 to be extracted from water. Anyone any ideas on how the o2 could be contained so it could be used in an aqualung for example?

Sarky

You'd want a massive electrolysis array. You don't get oxygen that fast from it, unless you could fix up a large surface area, high voltage system. Pressurising the air would be another big problem if the aqualung was going to be used more than a meter or two below the water's surface.

Capt'n Midnight

Not really practical due to the amount of electricity needed.

H2O means you need two electrons per Oxygen atom


http://www.cartage.org.lb/en/themes/Sciences/Physics/Electromagnetism/Electrostatics/Electricharge/CoulombsLaw/Examples/Examples.htm

How many coulomb's of charge is contained in the electrons of one kg of hydrogen?

One g of hydrogen has Avagadro's number of electrons.

Q = NA * e

where e = 1.602E-19 (C) , and NA = Avogadro's number = 6.02E23

Q= 96440.4 (C)

Since Oxygen is heavier and divalent you Get 8g (half a mole - 11 Litres at NTP) of Oxygen for every 96,000 Amp. Seconds = 26.7 AmpHours (Car Battery size)

This would have to be done at ~3 volts so you could rig up the car battery to give you about Two moles of O2 (44L = 10 Gallons / one Ounce of Oxygen) if you have four electrolysis cells in series.

A car battery weighs more than one ounce...

If Scuba divers use air at 200 Bar and it contains 20% O2 then your 44L would replace one litre of volume in a normal tank..

===============================

Options:
Some Algae release O2 bulbbles
Some plastics (silicon polymers ?) are gas permiable but not water permiable - about 2 m2 could be enough to breath for a person - near the surface in agitated water.
Reverse osmosis or vacuum extraction ?

dutchgold

Thanks for all your help, gave me some more to think about