“…These orders are useful as they allow to predict the zeolites behaviour at competitive ion exchange. The order of the cations is defined on the basis of the ion radii of the exchangeable cations [30,31], of the specific hydration energy [33], the presence of impurities, etc. Important criteria are zeolite electronegativity (determined by the Si/Al ratio), as well as the cation charge [22,29,34].…”