Diffused Layer ion in Electrix Double Layer

When KI is added to AgNO3 soln, so AgNO3 is in excess, collidal particle is AgI:Ag+ with diffused layer of I-, Why is the diffused layer not of NO3- when the anion in excess is NO3-?
If we had KI in excess in the above scenario, we get AgI:I- with diffused layer of K+ which fits logic of the ion in more concentration having more probablity of being the diffused layer.


(preferential adsorbtion of ion common to lattice for primary layer doesn't seem to factor in diffused layer?)


