A Zeolitic Octahedral Metal Oxide with Ultra-Microporosity for Inverse CO 2 /C 2 H 2 Separation at High Temperature and Humidity.

Separation of CO 2 /C 2 H 2 to obtain pure C 2 H 2 presents a challenge for the chemical industry. CO 2 -selective adsorbents are favored because of the convenient separation process. However, there are only a few CO 2 -selective adsorbents that can effectively isolate CO 2 from CO 2 /C 2 H 2 , and there is almost no research on CO 2 /C 2 H 2 separation under harsh conditions, such as with high temperatures and humidities. Herein, a zeolitic octahedral metal oxide based on ϵ-Keggin polyoxometalates is utilized for separations of CO 2 /C 2 H 2 at high temperatures and humidities. Single gas adsorption measurements show that the material only adsorbs CO 2 with almost no C 2 H 2 taken up. Dynamic competitive adsorption experiments show that the material efficiently separates CO 2 /C 2 H 2 , and highly pure C 2 H 2 is obtained directly. The robust material maintains a high separation performance at 333 K with 18.12 % water. The high stability of the material enables reuse without loss of separation performance.