The activated adsorption contribution to the hydrogen adsorption by birch activated carbon at 20.4 K

Literature data were used in studying hydrogen adsorption on activated birch charcoal at 20.4, 20, 30, and 32 K. The Δν=f(epsilon) curves were analyzed for adsorption isotherms at 20.4 and 24 K (Δν=νsub(20.4)-ν24 at a given epsilon, where epsilon=kT 1n P/P). They were shown to be analogous to the Δν=f(P) curves for slightly burned activated charcoal studied earlier (Δν=νsub(50-20.4)-νsub(20.4)) at a given pressure, P, where νsub(50-20.4) is the adsorption volume obtained as a result of warming the adsorbent to 50 K and then cooling to the initial temperature, 20.4 K). This analogy indicates the presence of ultramicropores with dimensions close to those of the hydrogen molecule. Pores remaining unfilled at 20.4 K are filled both when the temperature is increased to 24 K or during the course of a long experiment at 20.4 K. Thus a contribution of activation adsorption is shown