  An extension of the renormalized Jellium model which allows to study
colloidal suspensions containing trivalent counterions is proposed. The theory
is based on a modified Poisson-Boltzmann equation which incorporates the
effects of counterion correlations near the colloidal surfaces using a new
boundary condition. The renormalized charges, the counterion density profiles,
and osmotic pressures can be easily calculated using the modified renormalized
Jellium model. The results are compared with the ones obtained using the
traditional Wigner-Seitz (WS) cell approximation also with a new boundary
condition. We find that while the thermodynamic functions obtained within the
renormalized Jellium model are in a good agreement with their WS counterpart,
the effective charges predicted by the two theories can be significantly
different.
