Na2EdTA Vs. Na4EdTA?

Question

Which one of these two guys works better as a chelating agent in Food Industry or in Textile Industry? Why?

Answer 1

The Na4 salt is fully ionic, and is a better chelating agent - it attracts the metal ions more strongly.

Answer 2

From a chemistry point of view, the Na4 would work better or at least be a stronger chelate for weakly held ions. The problem is that if the Na2 works well enough, it is much cheaper than the Na4 and is the one used most often, usually in conjunction with another agent called NTA. It usually comes down to "good enough" and cheaper.