A method for detecting radioactive argon 37Ar produced in the soil by the nuclear reaction between 40Ca and fission neutrons is used for monitoring and detection of underground nuclear tests. In this regard, a relevant problem is to extract argon from soil gas with the elimination of impurities and conduct radioactive analysis. An industrial technology of low-temperature air rectification allows argon extraction in large quantities. However, this technology is prohibited by the CTBTO for on-site inspection purposes. This work is devoted to the study of materials for argon extraction and processing using the adsorption method and, in particular, the pressure swing adsorption (PSA) method. Traditional noble gas sorbents are used as materials, as well as high-silicon zeolites modified with transition metal nanoparticles (of the Y and ZSM-5 types), which feature an increased selectivity for argon. The study is carried out on a setup for examining the sorption and separation characteristics of sorbents. The technique for determining the characteristics of argon sorbents is based on the volumetric method (in the high-pressure range) and the preparative gas chromatography method.
The study of materials for argon extraction and processing allows to determine the sorbents with the highest selectivity for argon and to provide the possibility to conduct analysis of its radioactivity with the aim of underground nuclear test monitoring and verification.