A highly stable MOF with F and N accessible sites for efficient capture and separation of acetylene from ternary mixtures

Considering the important applications and purification requirement of C-2 hydrocarbons in the industry, the separation of C-2 in mixtures is a vital task. To achieve this goal, herein a new Ni2+-based metal-organic framework (MOF) has been solvothermally prepared by utilizing a tetrazolyl-carboxyl ligand and 4,4 '-bipyridine coligands as well as incorporating F- ions. The MOF shows a unique pillared-layer framework based on the novel metal-tetrazolate-carboxylate-fluorine chains, and possesses high chemical stability. Owing to the exposed adsorption sites of uncoordinated N atoms and F- ions in the channels, the MOF had high loadings for C2H2 and selectivity for C2H2 over C2H4, C2H6, CO2 and CH4. Under ambient conditions, dynamic breakthrough experiments revealed that the MOF performs effective separation of C2H2 from binary (C2H2-CH4, C2H2-C2H6, C2H2-C2H4, and C2H2-CO2) and ternary (C2H2-CO2-CH4, C2H2-C2H6-CH4, C2H2-C2H4-CH4, and C2H2-C2H4-C2H6) mixtures. The comparison based on the GCMC calculation revealed the crucial role of the accessible N and F sites for the selective capture of C2H2.

Automated summary

This study successfully achieved effective separation of C-2 hydrocarbons by utilizing a Ni2+-based MOF, which exhibited high loadings and selectivity for C2H2 and demonstrated effective separation of C2H2 from various mixtures. The crucial role of the MOF lies in its unique structure and exposed adsorption sites.