The adsorption characteristics of helium under low temperature.

• Experiments have been conducted to investigate the cryogenic adsorption characteristics of helium on activated carbon within the temperature–pressure range of 15–300 K and 0–1.5 MPa, utilizing volumetric method. • A comprehensive analysis have been investigated for installation design, adsorption equilibrium, adsorption isotherms, the isosteric heats of adsorption, heat leak calculation and the uncertainty. • This device can serve for selecting the suitable adsorbents which can be used in the system of helium isotope extraction and purification project in the future. To study the separation of helium isotopes by cryogenic adsorption, figuring out the adsorption characteristics of helium isotopes at low temperature is necessary. In this paper, a cryogenic adsorption measurement device has been established. It consists of a cryostat with a GM Cryocooler as cold source, a Setaram gas sorption instrument and a temperature controller. The helium-4 adsorption isotherms were studied under different temperatures and pressures (15–300 K, 0–1.5 MPa) by volumetric method. The results showed that a little helium was adsorbed by activated carbon at 300 K and 77 K. The amount of adsorbed helium increased with the temperature decreased from 20 K to 15 K. At pressures lower than 0.2 bar, the adsorption capacity increased rapidly as the pressure increased. Besides, the isosteric heats of adsorption were obtained, which was around 515 J/mol and changed little. Moreover, the cryogenic adsorption results were analyzed by Langmuir model and Toth model. [ABSTRACT FROM AUTHOR]