| 摘要 |
A method for purifying a minority constituent and concentrating it in a majority constituent of a gas mixture that also contains one or more other minority constituent(s) employs (i) a selective permeation step, (ii) next, a purification step, and (iii) finally a concentration step. In the selective permeation step, an initial gas mixture is passed through a membrane to yield a gas mixture that is enriched in the first minority constituent. In the purifying step, the first minority constituent is absorbed by a solid adsorbent which has a strong affinity for the first minority constituent, then following an elution step, a gas mixture that contains essentially only the majority constituent and the first minority constituent is formed. Finally, in the concentrating step, one or more successive adsorption and elution operations on a solid adsorbent, which has a strong specific affinity for the first minority constituent, are employed until an end gas mixture having the desired concentration of the majority constituent and the first minority constituent is obtained. This end gas mixture is highly enriched in the first minority constituent relative to the initial gas mixture. The procedure is particularly suited for detecting rare gases, e.g., xenon, and especially for detecting the natural and radioactive species in the atmosphere. The procedure can be employed in association with nuclear spectrometry to detect and monitor the presence of trace gases in the environment around nuclear installations.
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