hydrogen seperation

[linkintiger]

i was wonder one of the guys old chemist teacher mention something that in the setup like dry cell hydrogen is concentrating more on the positive plates and oxygen i more concentrating on the negative plates you think is it true?

[oicu812]

uh oh!!! I think the alzhiemer is starting to kick in, he's got it alittle reversed. In his defence I think he might have been refering to hydrogen ions forming on the positive plates(anode) and migrating to the negative plates (cathode) where hydrogen gas is formed . the oxygen side is the oppisite. now if you really want to get confused read up on batteries and what happens durring discharge.its the complete reverse.

[Philldpapill]

You can figure out which plate produces what with a bit of chemistry. In water, H20 is actually a big mess of H+ and OH- ions floating around - constantly combining and disassociating in a nice balance. However, if you start introducing an electric field, and supply of electrons, into the mix, the H+ ions will start grabbing an electron off the negative plate, and pairing up with his other stable buddies - other H+(plus -e's) to form H2. On the positive plate, the same sort of thing happens, except this plate is sucking electrons OFF of the OH- ions, and splitting the ion in the process. The result is O2 molecules forming, and H+ ions hanging around in the water until they recombine/disassociate with more OH- ions. The end result is that you get H2 bubbling up on the negative plates, and O2 bubbling up on the positive plates. The corrosion you get on the positive plates is a direct result of the oxidation reaction(O2 forming) going on at the positive plate. In other words, the O2 that forms is in such close, microscopic proximity to the actual plate surface, that some of the O2 molecules end up pairing up with the metal atoms of the plate surface, forming rust, or other oxides.

[Philldpapill]

By the way, oicu - Have you ever measured the voltage across your HHO cell just after you turn the power off? Have you noticed the small, but measureable voltage? It's acting as a battery for a little while until the H2 and O2 bubbles go away from the plates. Pretty cool stuff, and I wonder what kind of energy density is actually on the plates... Man, I'm going to try and measure this now. I wonder if we can actually make a REAL fuel cell with this...

What I imagine is, applying a steady flow of hydrogen gas bubbling up right at the negative plate, and oxygen bubbling up at the positive plate. Instead of connecting the cell to a battery source, connect it to an ammeter and see if there is any current flowing due to the electrochemical process going on. Basically, it would be an HHO cell operating in reverse - a true fuel cell, but without the PEM.

[oicu812]

By the way, oicu - Have you ever measured the voltage across your HHO cell just after you turn the power off? Have you noticed the small, but measureable voltage? It's acting as a battery for a little while until the H2 and O2 bubbles go away from the plates. Pretty cool stuff, and I wonder what kind of energy density is actually on the plates... Man, I'm going to try and measure this now. I wonder if we can actually make a REAL fuel cell with this...

What I imagine is, applying a steady flow of hydrogen gas bubbling up right at the negative plate, and oxygen bubbling up at the positive plate. Instead of connecting the cell to a battery source, connect it to an ammeter and see if there is any current flowing due to the electrochemical process going on. Basically, it would be an HHO cell operating in reverse - a true fuel cell, but without the PEM.

Yes I have... I find it facinating that the same metal would have a difference in potential. could it be from the slight oxidation at the anode? From taking my cells apart I've noticed a dark film that developes on the positive plates and on the positive side of the bi-polar plates. Have you ever wondered about using dissimilar metals in our cells? like maybe anodized titanium and stainless steel or even nickle. The less noble metal would become the anode durring discharge. Depending on the metal used I would think you could get 200 or 300 milivolts accross each cell. If you used a thin foil film like stainless steel foil and titanium foil you could pack alot of cells into a drycell. By anodizing the titanium foil you could increase the surface area by a thousand times making one hell of a battery!
What do you think? is it a crazy thought?

[RustyLugNut]

You can figure out which plate produces what with a bit of chemistry. In water, H20 is actually a big mess of H+ and OH- ions floating around - constantly combining and disassociating in a nice balance. However, if you start introducing an electric field, and supply of electrons, into the mix, the H+ ions will start grabbing an electron off the negative plate, and pairing up with his other stable buddies - other H+(plus -e's) to form H2. On the positive plate, the same sort of thing happens, except this plate is sucking electrons OFF of the OH- ions, and splitting the ion in the process. The result is O2 molecules forming, and H+ ions hanging around in the water until they recombine/disassociate with more OH- ions. The end result is that you get H2 bubbling up on the negative plates, and O2 bubbling up on the positive plates. The corrosion you get on the positive plates is a direct result of the oxidation reaction(O2 forming) going on at the positive plate. In other words, the O2 that forms is in such close, microscopic proximity to the actual plate surface, that some of the O2 molecules end up pairing up with the metal atoms of the plate surface, forming rust, or other oxides.

Another Item of Interest that belongs in a FAQ.

[astrocady]

Another Item of Interest that belongs in a FAQ.

I printed it and hung in on my wall. Thanks Phil

[Philldpapill]

It's an interesting idea, but I believe - and I could very well be wrong - that the reason we are seeing a voltage across the plates is due to the H2 and O2 bubbles lingering on the plates, causing a votlage potential. I think...

[oicu812]

you might be right... by the time the bubbles are gone the voltage drops to nothing.

[Philldpapill]

I sure hope I'm right about it... If that IS in fact what is going on, then that's pretty cool. We can make a real fuel cell that takes hydrogen gas, and converts it back into water and electricity by bubbling up very fine bubbles along a plate surface, and oxygen bubbles along the other plate surface. I can't wait to try some experiments.