The decrease in the SO4 2/Cl separation factorwith increasing cCl;tot in a model ion exchange system. (a) For a fixed total concentration of 4 meq/L total SO4 and a range of dissolved Cl concentrations that might be encountered in potable water sources.(b) For values of cCl applicable to resin regeneration conditions.The assumed conditions areKSO4=Cl ¼ 20 (based on c in meq/L and q in meq/g), 5 meq/L total ion exchange sites, cSO4;tot ¼ 4 meq/L, and cCl;tot ranging from less than 1 to 3500 meq/L.