| 摘要 |
<p>PROBLEM TO BE SOLVED: To produce an adsorbent having a high nitrogen adsorptive capacity at a low cost by lithium ion-exchanging a crystalline faujasite-type zeolite containing strontium, calcium, magnesium within specified ranges and moreover sodium and potassium within specified ranges. SOLUTION: In an adsorbent to be used for obtaining concentrated oxygen gas from air, a crystalline faujasite-type zeolite containing not less than 10% and less than 70% of a mixture of strontium, calcium, and magnesium, not less than 7% of sodium, potassium, and their mixture, and not less than 25% and less than 85% of lithium as exchangeable cations is used. The desiring adsorbent is produced by lithium ion-exchanging the crystalline faujasite-type zeolite. The zeolite to be used is preferably a crystalline faujasite-type zeolite with 2.0-5.0 SiO2 z/Al2 O3 mole ratio since higher efficiency is provided in the case the zeolite has larger micro pores.</p> |
