  We study electrostatic mechanisms of destabilization of highly asymmetric
electrolytes. For this purpose, we perform primitive model Monte Carlo
simulations of charged macroions immersed in multivalent salt solution. At low
salt concentration, the macroion effective charge is reduced due to multivalent
counterion adsorption. At high salt concentrations, the macroions become
overcharged so that their apparent charge has the opposite sign to the
stoichiometric one. The inverted charge is growing up to a saturation value
upon further increasing the salinity. The system remains stable at low as well
as at very high salt concentrations. In the intermediate region, close to the
macroion isoelectric point, we observe macroion aggregation. The obtained phase
behaviour closely resembles polyelectrolyte-induced instability of colloidal
dispersions.
