Dynamic Flow Method

In 1951, Loebenstein and Deitz [1] described an innovative gas adsorption technique that did not require the use of a vacuum. They adsorbed nitrogen out of a mixture of nitrogen and helium that was passed back and forth over the sample between two burettes by raising and lowering attached mercury columns. Equilibrium was established by noting no further change in pressure with additional cycles. The quantity adsorbed was determined by the pressure decrease at constant volume. Successive data points were acquired by adding more nitrogen at the system. The results obtained by Loebenstein and Deitz agreed with vacuum volumetric measurements on a large variety of samples with a wide range of surface areas. They were also able to establish that the quantities of nitrogen adsorbed were independent of the presence of helium.