Adsorption of Polyethylene Glycol at the Interface of Dicalcium Silicate - Sodium aluminate solution

Surfactants, such as polyethylene glycol (PEG), are widely used to inhibit the secondary reaction of dicalcium silicate (beta-CaOSiO2) in sodium aluminate solution. The adsorption isotherm of PEG on beta-CaOSiO2 in sodium aluminate solution at 80 C was researched in this paper. It was found that the type of surface adsorption of PEG is saturated adsorption, and the adsorption behavior belongs to "S"-type, according with the multi-molecular layer adsorption model of the Freundlich Equation. The surface coverage of PEG close to saturated adsorption derived from the specific surface area of beta-CaOSiO2 is 0.723 mol/d mu(2). The relation curves between the surface pressure and the molecular area of adsorption film were obtained according to the adsorption results at the solid-liquid interface by Gibbs formula. The variation of interfacial energy caused by adsorption, as well as the relationship between the relation curves and the type of adsorption was also discussed.