HYDROXYL-GROUPS AND SURFACE-POTENTIAL OF SYNTHETIC ALUMINA

The total potential of the interface in aqueous suspensions of synthetic Al2O3 is calculated from conductometric titration data of acidic and basic surface-active sites. The time of rotational correlation of a spin probe in Al2O3 dispersions is determined using the EPR method; the viscosity of the dispersion medium within the slipping plane is found to be greater than that in the bulk solution by a factor of 4 - 4.5. The zeta-potential, calculated with account for the viscosity change, and the Psi(delta)-potential, calculated for the thickness of a hydrodynamically stationary layer equal to 1.5 nm, are close to the value of the total interfacial potential.