Effect of polymer molecular weight on the adsorption of polyacrylic acid at the alumina-water interface

The adsorption and electrokinetic characteristics of alumina suspensions in the presence of polyacrylic acid as a dispersant have been studied. The adsorption isotherms exhibit high-affinity Langmuirian behaviour. The adsorption density decreases with increasing in pH, while it increases with increasing molecular weight of the polymer. Electrokinetic studies indicate specific adsorption at and above the isoelectric point of the alumina sample. Possible mechanisms of interaction between alumina and polyacrylic acid are discussed