Temperature-Compensated, Differential Tensimeter for Measuring Gas-Adsorption by Low Surface-Area Solids

An apparatus is described which permits convenient determination of gas adsorption of solids having lower adsorption capacity at subatmospheric pressures. The apparatus consists of a differential micromanometer whose two arms are connected to a pair of sample and reference burets of nearly equal volume for dosing gas into sample and reference cells also of nearly equal volume. When the two cells are immersed in the same temperature bath this design greatly reduces measurement uncertainties due to fluctuations in temperature. Surface areas as small as 1000 cm2 can be measured through volumetric measurements of nitrogen uptake at overall pressures between 3 and 30 KPa at liquid nitrogen temperature.