an improved process for production of mixed cation - exchanged adsorbents that involves a single pass ion exchange . the precursor zeolite is treated with a combined essentially stoichiometric and excess solution of desirable weakly held and strongly held cations so that the resultant zeolite has the required mixed cation composition , while consuming smaller amounts of weakly held cation . ion exchange post - treatment includes an optional equilibration step to ensure a uniform adsorbent and an optional washing step .