[Reddart]

I have a polymer I am trying to remove as many stray ions as possible. I can use anionic ion exchange resin to remove some impurities, but unfortunately the polymer sticks to cationic ion exchange resin, so I cant use those for metal cation removal.

Has anyone used membranes to purify ions out of polymers (or large protiens)?

I was thinking about using these types of bottles: https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-purification-isolation/protein-dialysis-desalting-concentration/dialysis-products.html#product-list-table

[Arkcon]

Any of those work for large bio molecules.  What's the nature of your polymer?  You'll have to know the MW range, and charge properties to select the proper dialysis membrane.