Author Topic: Electrolysis membrane  (Read 8561 times)

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Bandil

  • Guest
Electrolysis membrane
« on: October 17, 2001, 08:03:00 PM »
Hi!

I was just testing some membranes for cell divided electrolysis today, for my reduction tomorrow. I used an unglazed clay pot, and filled it with dilute HCl and some dilute HCl on the outside. I really didnt expect to be able to pass current through it, but i wanted to be sure, before making sheep gutted version tomorrow. As expectet not a single milliamp passed through. I used 15 V on each side of the pot wall(cleaned it thourghly etc) attached to lead electrodes.

Have either of you been able to pass current through one of these buggers? I doubt it, so ill by some sheep gut from the butcher tomorrow. I have higher hopes for this material! I will of course post my results, as i am attempting to reduce with Zn-HCl and electrolytical at the same time.

Regards
Peter

hest

  • Guest
Re: Electrolysis membrane
« Reply #1 on: October 17, 2001, 09:03:00 PM »
It take some time for the acid to penetrate theclay (houers), before that it's a good insulator.

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #2 on: October 17, 2001, 09:45:00 PM »
So i have to leave it in the solution for a while? I guess it does not have to be hooked up on the current meanwhile. The claypot is currently soaking 10% HCl. Is that doable, or should i usem what i plan on using for catholyte?

Regards
Peter

hest

  • Guest
Re: Electrolysis membrane
« Reply #3 on: October 17, 2001, 10:11:00 PM »
Sounds good to mee.

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #4 on: October 18, 2001, 01:08:00 PM »
Allright! This morning the clay pot pulled 0.2 A at 24V... Its somewhat better than 0.0A, but still not good enough. Dp you think the conductivity will improve, if it is soaked for another 24 hrs?

hest

  • Guest
Re: Electrolysis membrane
« Reply #5 on: October 18, 2001, 02:20:00 PM »
No, not much. mabee a bigger elektrode/setup ??

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #6 on: October 18, 2001, 02:38:00 PM »
No... The electrodes had a surface area of about 15 cm2, which gives it a current density of 0.013 A/cm2(thats a bit small right?), which is way to small. I really dont want to regulate the voltage more up, as it already is 24 V. I think ill have a go with the lamb gut setup.

Ideas?

Regards
Peter

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #7 on: October 18, 2001, 08:37:00 PM »
Just attemped electrolysis with pig intestines as membrane. The g... da... thing broke after two minutes of running. So much for the natural approach!

I will try to get other materials for the membrane. In first attempt it will be a flower pot with thinner walls.

Any ideas for other practical materials for use as membrane?

Regards
Peter

Rhodium

  • Guest
Re: Electrolysis membrane
« Reply #8 on: October 18, 2001, 09:08:00 PM »
A fritted glass disc? They are available in all porosities from chem equipment suppliers.

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #9 on: October 18, 2001, 10:17:00 PM »
Do you have more details on the membrane? Name etc... Is it something that can be bought from Fluka or alike?

Thanks
Regards
Peter

Rhodium

  • Guest
Re: Electrolysis membrane
« Reply #10 on: October 18, 2001, 11:29:00 PM »
Not chemicals suppliers, but rather those selling glass and equipment. I have no exact source in the US.

Osmium

  • Guest
Re: Electrolysis membrane
« Reply #11 on: October 19, 2001, 12:02:00 AM »
I hope you didn't use 15 or even 24 volts on those intestines.

What about dialysis membranes? Anybody ever tried that?

I've seen soft polyurethane foam being used in electrolysis reactions. Improvised and ghetto, but it worked (or so I was told).

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #12 on: October 19, 2001, 12:15:00 AM »
I looked at dialysis membranes some time ago, and boy did i get confused. There where cathion one way, both ways, protein permitable and yadeyadeyade. There where litteraly 100's of different types, so i did not know which one to get. Any ideas on which ones of the dialysis membranes, that would work?

Regards
Peter

Osmium

  • Guest
Re: Electrolysis membrane
« Reply #13 on: October 19, 2001, 12:30:00 AM »
The cheapest, most general one. Or the one with the prettiest colour  ;)

Since the current is transported by the movement of the water molecules the pore size doesn't have to be big at all. Smallest pore size should be more than adequate, and will also help keeping the solutions separate.

I really don't know if it will work, just an idea. Ask the manufacturer for some free samples and find out if it works and which one is best.

Antoncho

  • Guest
Re: Electrolysis membrane
« Reply #14 on: October 19, 2001, 04:52:00 AM »

Or the one with the prettiest colour  ;)




Speaking of which - i don't know if a regular condom would pass molecules of water but it surely lets through gaseous HCl - at good rate, BTW! (And i used some really tough, studded Soviet condoms from my late grandpa's stock ;D )

HCl molecule is bigger than H2O, does anything else matter?

You also might have to stretch it for this.

Antoncho


pimpmaster

  • Guest
Re: Electrolysis membrane
« Reply #15 on: October 31, 2001, 09:44:00 PM »
need a membrane how´s about this procedure. wet a sheet of paper, wrap it several times around a large test tube or beaker,folding it in to close at the bottom. mold the paper into shape, then coat it inside out with a solution made by dissolving 75 grams of gelatin and 100g K4Fe(CN)6 in one liter of water. When the cup has drained and cooled it should be removed and inverted until dry.
sounds nice except for the K4Fe(CN)6 i wonder what could be used instead ?

sYnThOmAtIc

  • Guest
Re: Electrolysis membrane
« Reply #16 on: November 01, 2001, 11:47:00 AM »
Wow people are finally starting to get into electrochemical cells lately.... Pinky is using a stainless steel cup in a pot of acid for his reduction. No worry about goods being oxidised since there is absolutely no particle travel but conducts electricity fine. Machined carbon cups and unglazed fritted porcelin mugs can be bought and work much better thatn clay.

Natrix

  • Guest
Re: Electrolysis membrane
« Reply #17 on: November 01, 2001, 12:07:00 PM »
I think gore-tex could be used for a membrane.

dwarfer

  • Guest
Re: Electrolysis membrane
« Reply #18 on: November 02, 2001, 03:40:00 AM »
.2ampsat24 v is an unusually low current for that V:

?? get another pot:

10 V should give you 2X that much: although without knowing your set up, this is specious reasoning...

The worlds easiest set up is a standard pot inserted into the BOTTOM of a cut-off 2 liter soft drink bottle.

The cathode is in the bottom, symettrically placed, the teflon wrapped current supply wire passes through a sealed hole..

There IS a standard pot which will JUST FIT, and the tera cotta RIM rests on the rim of the cut off bottle...

Note that this seals the catholyte from air, enhancing appropriate reactivity therein

Now you take another 2 liter soft drink bottle, cut it off at the appropriate height to accomplish the following:

1.  melt a hole in the screw cap 3/8 diameter to pass the carbon electrode anode which you got from a welding supply shop for $.50

2.  A standard condom will be passed thru the screw on opening from the bottom, maybe 1/2 inches worth, and the screw on cap will be screwed on tightly enuff to hold it in place, and not so tight as to rip it. They ARE tough..

3. the top section will be placed INSIDE the tera cotta pot:
this will necessitate 3 verticl slits symettrically place so the "legs" thus form can overlap to accomodate the reduced diameter of the pot inside...

4.  The height will be adjusted so that the condom reaches down to about an inch from the pot bottom.

5.  Your 10 to 15% HCl will be added to the pot, and to the condom through the anode hole, keeping the levels about thesame.

6. You will insert the anode, NOT allowing contact with the skin.

This dual membrane system will have significantly less R than your set up: probably because of the large submerged pot surface area.

It was found to be as effective as a pressurized systemI built in reductive process.  And takes about maybe an hour to build...

I'll take some pictures...

:-[  ;D  :)  8)  ::)  :(  :o  :P

dwarfinger: He's the dwarf wit' der GOLdenNose <hmm>

Antibody2

  • Guest
Re: Electrolysis membrane
« Reply #19 on: November 02, 2001, 03:12:00 PM »
please do dwarfer

"All those memories lost like rain..."