Dear all,

I am currently working on the extraction of Calcium from a solution containing various ions and organic molecules using a weak acid cation resin. Because my solution is acidic (pH=4,2; resin pH working range = 5-11), I added ammonium hydroxide (final solution pH = 9) before running it through the column.

When I run the solution through the column, bubbles form within the resin (small and big ones, everywhere). I ran a control by feeding the resin demineralised water with a pH adjusted to 9 with ammonium hydroxide, and no bubbles formed. Almost no bubbles form when I run the solution with almost no ammonium hydroxide (pH=5).

Therefore, I am wondering what causes the formation of those bubbles? Would you have an idea of which reaction, between my solution, ammonium hydroxide, and the resin could lead to the formation of gases?

Thank you very much for thinking with me,

Laetitia