CO <sub>2</sub> Chemical Trap and Electronegative Microenvironment Enable Metal–Organic Framework with One‐Step Ethylene Purification from Quaternary Mixture
Mingze Zheng, Zhi Fang, Wenjuan Xue, Tongan Yan, Hongliang Huang, Chongli Zhong
Abstract
Abstract One‐step purification of C 2 H 4 from a four‐component CO 2 /C 2 H 6 /C 2 H 2 /C 2 H 4 mixture with a single adsorbent is of great significance but very challenging. Herein a feasible and general strategy is reported for constructing chemical traps in MOF featuring an electronegative microenvironment in the pore wall for one‐step purification of C 2 H 4 from the four‐component mixture. The enzyme‐mimicking Zn‐OH sites in CFA‐Zn‐OH, acting as a CO 2 chemical trap, can efficiently fix CO 2 while the electronegative pore wall in MOF ensures the preferential adsorption of C 2 H 2 and C 2 H 6 impurities, thus leading to the one‐step purification of C 2 H 4 from a four‐component mixture. Mechanism studies reveal that the Zn‐OH sites in CFA‐Zn‐OH can chemically fix CO 2 impurity in a reversible manner to form bicarbonate Zn‐HCO 3 , mimicking the carbonic anhydrase. In addition, the negative electrostatic potential of the pore wall allows CFA‐Zn‐OH to preferentially capture C 2 H 2 , and C 2 H 6 impurities, thus ensuring one‐step C 2 H 4 purification from the four‐component mixture. Column breakthrough experiments validated its ability for one‐step C 2 H 4 purification on from the four‐component mixture and C 2 H 4 with a purity of 99.9% can be directly harvested.