Dielectric Behavior of Water Adsorbed on Alumina

Abstract

The dielectric behavior of water adsorbed on gamma alumina has been investigated by measuring dielectric constant and loss tangent as functions of temperature (0–86°C), amount adsorbed (0–220 mg H₂O/g Al₂O₃), and frequency (50 cps—100 kc). The results are those expected for a multilayer adsorption system in which the monolayer is very strongly bound and in which molecules in layers above the first are relatively free to orient under the influence of applied field. The temperature coefficient of the vapor pressure of the system for fixed amount adsorbed has been measured to provide an enthalpy of adsorption which has been compared with enthalpy of orientation obtained from the dielectric measurements.