Sciencemadness Discussion Board

Can a coffee filter be used as a membrane for electrolysis?

redshield5 - 8-4-2023 at 17:57

I am currently working on washing/cleaning/extracting potassium chloride from Morton Table Salt replacement. After I finish, I'll post a writeup if all goes well. My intention is to get *pure* potassium chloride from this stuff (I don't want to order things online if I don't have to!) which I intend to reduce with electrolysis to form an aqueous solution of potassium hydroxide .

Anyway, I am wondering if a single unbleached coffee filter would function as a membrane between the containers at anode and cathode of my electrolysis device. I have seen a YouTuber use a single cotton ball as his membrane, so am just curious if I can use one of my unbleached filters, as I don't have any cotton balls in my room. Thank you! I know this sounds boring but I have big plans lol

Rainwater - 9-4-2023 at 01:57

No, the pores are much to big. Printer paper will work, but not very well.
If you search the forums you will find what your looking for. This topic has been covered alot

Johanson - 9-4-2023 at 19:36

Try:
1. The filter paper from a wet/dry vacuum cleaner (shop vac). It's a lot thicker.
2. Unglazed pottery
3. Stiff felt paper from an art/hobby store. Concentrated caustic potash might burn through this stuff, though.
4. Rip the separator paper out of an alkaline battery, wash it real good, and try that.
5. If must use cellulose, grab a bunch of cotton or dryer lint, mix with bentonite clay or kaolin clay, and roll it out into sheets.
Heck, I'm just throwing out low budget ideas

Chemgineer - 10-4-2023 at 07:28

+1 for the unglazed clay pot, this can work well. I did have to sand paper mine slightly though to get it to start conducting.

Laurelium - 10-5-2023 at 13:20

I have seen nylon mesh being used as membrane to separate H2 + O gas from water through electrolysis although I don't recall the mesh size. Not sure if it applies to your situation.

Rainwater - 10-5-2023 at 16:06


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Romix - 11-5-2023 at 07:00

I've used cotton wool that nurse stick on my hand with plaster after the injection of antipsychotic medication.
Works great.
Two 500ml bottles, one pen that screws in from both sides and a soldering iron, you can burn holes with a lighter, but I finding it easier using a soldering iron.
Place some cotton wool in the middle of a pen, burn hole in one bottle, screw pen in tight, then do the other end with the same technic. Gluing anything in the bottles will eventually leak, because KOH and Cl2 dissolves most glues!
Connect hose to the lid of the Anode bottle and bubble it in water, not to poison your self with chlorine, some still will pass trough the water, you'll smell it, trust. You need to know polymer that won't react with Cl2. I've used cable sleeve taken out of broken CRT TV. Your water will have a mixture of acids in it.



[Edited on 11-5-2023 by Romix]

Romix - 12-5-2023 at 03:19

And best to use a HDPE bottle out of milkshake for the Cathode, because when concentration of KOH gets high it will crack the bottom of the PET bottle in hours.