A Zeolitic Octahedral Metal Oxide with Ultra-Microporosity for Inverse CO2 /C2 H2 Separation at High Temperature and Humidity

Abstract

Separation of CO₂ /C₂ H₂ to obtain pure C₂ H₂ presents a challenge for the chemical industry. CO₂ -selective adsorbents are favored because of the convenient separation process. However, there are only a few CO₂ -selective adsorbents that can effectively isolate CO₂ from CO₂ /C₂ H₂ , and there is almost no research on CO₂ /C₂ H₂ 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 CO₂ /C₂ H₂ at high temperatures and humidities. Single gas adsorption measurements show that the material only adsorbs CO₂ with almost no C₂ H₂ taken up. Dynamic competitive adsorption experiments show that the material efficiently separates CO₂ /C₂ H₂ , and highly pure C₂ H₂ 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.

Keywords: CO2/C2H2 Separation; High Humidity; High Temperature; Polyoxometalates (POMs); Zeolitic Octahedral Metal Oxides.