Sciencemadness Discussion Board

Testing Ionic Membranes

Geekineer - 21-12-2015 at 13:33

I need to measure the relative (not calibrated or absolute) performance of anion membranes. Looking for the best membrane to use in a special electrochemical cell. Don't have access to impedance spectroscopy but can put together just about any type of electronics required, i.e. measure voltage, current, resistivity. Can generate AC/DC signals......

My cell so far is a nice two part 3D printed (water tight) arrangement that clamps the membrane. It has input and output fittings on both sides of the membrane cavities. So I can input (pump if required) liquids in and out.

What I need to know is what chemicals and electrical set up will tell me the relative ionic flow (without being over ridden by any background electrical path). There shouldn't be any electron flow if its a true ionic membrane - but that's part of what I need to test.

1. Was thinking of using easy to attain/make electrolytes like Copper sulphate, or Ferric Chloride.
2. What should I make the anode and cathode electrodes out of. OK if they are one time use doing to plating out etc.
3. What about polarities?
4. Do I measure voltage, current, AC or DC or something else.

Sorry if this souds lame - will appreciate any and all comments.

[Edited on 22-12-2015 by Geekineer]

Sulaiman - 22-12-2015 at 06:10

Could you make your actual 'special electrochemical cell' with a replaceable membrane,
probably best anyway to allow replacement due to wear and tear,
then you could test under actual conditions.

Geekineer - 23-12-2015 at 12:49

What I have now is just that - a test cell with replaceable membrane. Any suggestions on the electrolytes for the test? Something simple and inexpensive?. Preferably not to acidic. Developed some 'homemade' carbon based electrodes so just about anything will work for relative measurements.

[Edited on 23-12-2015 by Geekineer]

elementcollector1 - 23-12-2015 at 18:33

Is polylactic acid sufficiently resistant to various chemicals to warrant a cell being 3D-printed out of it?

smaerd - 26-12-2015 at 07:07

I'm a little confused as to what you wish to test here?

Are you making an ion selective electrode? It doesn't sound like it. I'm not sure what "relative ionic flow" is. Can you please elaborate?

Are you trying to make a membrane that only allows certain ions to permeate it's boundary, or something else?