Kinetic Study of Adsorption of Poly (acrylic acid) and Sodium Dodecyl Sulfate on Alumina Particles

The adsorption kinetics of poly (acrylic acid) (PAA) and sodium dodecyl sulfate (SDS) on alumina particles at pH 5.2 was investigated by measuring the amount of PAA and SDS adsorbed and the dispersion stability of suspensions with time. The adsorption of single systems of PAA and SDS showed a similar behavior that the adsorption increases rapidly and then saturates. In the simultaneous adsorption of PAA and SDS at two initial concentrations of SDS which correspond to the formation of a monolayer and a bilayer of SDS, respectively, the adsorption of PAA increased markedly at an early stage, decreased, and then became constant, while the adsorption of SDS exhibited a similar behavior to that of SDS alone. In addition, the dispersion stability of alumina suspensions with time was also affected by adsorption of PAA/SDS. The mechanism of adsorption kinetics of PAA and SDS on alumina particles was discussed.