PARTICLE ADHESION IN MODEL SYSTEMS .15. EFFECT OF COLLOID STABILITY IN MULTILAYER DEPOSITION

The deposition of uniform spherical colloidal hematite on glass of the same and opposite sign of charge was studied using the packed column technique. The recently developed multilayer model explains the data on systems of like charge for which the previously used monolayer model would fail. The deposition experiments at ionic strengths exceeding the critical coagulation concentration could also be fitted by the same multilayer model. The adhesion was strongly affected by the addition of the sulfate ion to the dispersion due to the complexation with hematite particles, which caused charge reversal. The data in aqueous systems agreed with those in 50% ethanol/water mixture when the difference in viscosity was taken into consideration. The obtained mass transfer efficiencies were related to the theoretically calculated instability ratios. © 1992.