Chlor Alkali Membranes

Quote: Originally posted by Jstuyfzand

I am planning on building a chloralkali cell to then make hydrochloric acid

Quote: Originally posted by Jstuyfzand

Ps: I have tried the flower pot, did not went well.

Quote: Originally posted by experimenter_

Quote: Originally posted by Jstuyfzand   Ps: I have tried the flower pot, did not went well. May I ask what did go wrong? Do you think it is something that can be solved with a better approach or the flower pot idea is fundamentally wrong? I was thinking also of a simple "salt bridge" using only filter paper to bridge the two compartments but I wonder also if this is capable from keeping the solutions unmixed. Also, Im afraid that the high resistance of that "bridge" may cut the electrolysis current to very low amounts. I've seen online that there are some educational chloralkali cells available for shopping but I would like to keep it the simplest possible.

Quote: Originally posted by Jstuyfzand

The flower pot limited the current to extremely low current, and regarding the salt bridge, I have my doubts, the same as yours. I wondered if a silicon kit mixed with a salt like NaOH could conduct the electricity and act like a membrane and transfer the ions.

Quote: Originally posted by experimenter_

Quote: Originally posted by Jstuyfzand   The flower pot limited the current to extremely low current, and regarding the salt bridge, I have my doubts, the same as yours. I wondered if a silicon kit mixed with a salt like NaOH could conduct the electricity and act like a membrane and transfer the ions. Hm, I see. Did you mean silica gel bridge ( http://www.sciencemadness.org/talk/viewthread.php?tid=20816#... ) instead of silicon kit? (I don't know what silicon kit is)

Quote: Originally posted by Jstuyfzand

I do yes, but I just realized NaOH dissolves the gell, damnit, I am just going to try densely packed filter paper with NaOH

Quote: Originally posted by Tsjerk

Did you guys ever think about using agarose for the salt bridge? After solidifying it is practically insoluble, and 3% gel makes a really sturdy gel. It practically conducts the same amount of current as the solution you prepared it in would normally do. In bigger (250gramish) amounts the really pure high quality stuff is about one euro per gram, but at 3% that would last you a life time. It is even remold-able after melting at 100 degrees. Ps. I believe you can also find it at an vegan alternative for gelatine, I don't know about the purity of that stuff, but as a role of the tumb; If it is white it is pure. [Edited on 22-3-2016 by Tsjerk]

I will look into both, sounds promising, I assume you just mix in some electrolyte into the gelatin? Going to look at it now!
1€ a gram sounds expensive, and I try to keep the costs zero, I'm still a kid

Quote: Originally posted by Tsjerk

Yes, it also called agar or ''agar agar'', the cheap stuff is usually brownish and a bit less pure, but for a first try and depending on what you want to make it is probably fine. About the price; don't forget you only need 2-3%, so a couple of grams will already make you 100ml of the gel. To make it you make a suspension of it in your electrolyte of choice and heat it to 100 degrees while stirring, hold it against light to check if it completely dissolved, this usually takes a couple of minutes. When it cools down it solidifies, poor it in a watertight mold that can stand 100 degrees before it does. You can let the solution cool down to about 50 to 60 degrees before it solidifies, when you want to melt it again you have to heat it to 100 degrees again. Edit: To get any (charged) impurities out, you could just run your cell with plain electrolyte for multiple hours. This will "wash" any charged stuff out of the gel. Your electrodes have to be able to handle the voltage you run at for prolonged time though. [Edited on 23-3-2016 by Tsjerk]