H2/O2 seperation membrane with electrolite

[robwaddell]

Hello all,

I'm wondering if anyone has information on what membrane I might use to seperate my electrodes in an electrolite solution so that I can get H2 off of one electrode and O2 off the other electrode in an electrolyzer. Therefore the membrane must allow the creation of H2 and O2 using electricity, but have the electrodes sepearated so I get pure H2 off of one and pure 02 off of the other electrode. Any help would be great as I'm a mechanical engineer and not too hot on chemistry and electrisity.

 

[radomir]

Once upon a time when I was a kid we did water electrolyze experiment in a school. No membrane was used, only those laboratory test tubes over the electrodes, one captivating O2 (probably on anode but being a mechanical engineer also I am not to be trusted in this electro-chemical matters) and the other H2.

Therefore there is no need for membrane just some vessels or tubes connected to vessels placed above the electrodes, partialy encapsulating them (the bottom portion is open to electrolyte and the wires are connected from that side). Since both products are gaseous they will readily fill the vessels.

 

[dags]

I have considered Nafion for a similar application. Usually it is treated with acids to yield a solid polymer electrolyte for electrolysers. Nafion allows the water to pass, but unknown whether it also passes electrons or ions. . . anyone else?

 

[elvis932]

Hello, if I remember correctly, the H2 and O2 will be generated on opposite electrodes. Tubes slightly above the electrodes will collect the gas streams separately, the one with H2 will have twice the volume of gas as the one with o2. PS. the electrolosis reaction is relatively unaffected by pressure, so you could generate gas at high pressure; thereby eliminating the need for a compressor for storage.

On another note, a new technology is to use an apparatus similar to a hydrocyclone to separate H2, O2, and steam. also membrane technology is generally not economic for gas separation, because of the high pressure loss across the membrane (or high capital cost), and subsequent recompression.

Hope this was helpful

Melvin Hakes(Chem Eng)