Methyl-functionalized flexible ultra-microporous MOF for efficient SF6/N2 mixture separation

In the semiconductor industry, SF6/N2 mixtures must be properly disposed of to protect the environment. Herein, three metal-organic frameworks with densely methyl-functionalized pores were designed to capture SF6. Among them, Zn(TMBDC)(DABCO)0.5 had the most suitable channels with the absorption capacity of 4.61 mmol/g, and the highest SF6/N2 selectivity is 239 at 298 K and 1 bar. Theoretical calculations indicated that introducing methyl groups provided more affinity sites that could bind SF6. Cyclic breakthrough experiments confirmed the ability to directly separate SF6 from a SF6/N2 mixture. This porous coordination network provides a method to construct other MOFs to separate SF6/N2 mixtures and other fluorinated gases.