Study on the Adsorption Separation of CHF₃/N₂ by an SIFSIX-3-Ni Metal–Organic Framework

CHF3 is a strong greenhouse gas, and its potential greenhouse effect is 14,800 times that of CO2, so recycling and reusing CHF3 positively contributes to environmental sustainability. Therefore, a purification and recovery process development based on the adsorption of CHF3 has become an urgent requirement. In this paper, an ultramicroporous fluorine-containing pillared metal–organic framework (MOF), SIFSIX-3-Ni, was applied to the separation of CHF3/N2. The adsorption and separation properties of SIFSIX-3-Ni for CHF3/N2 were confirmed by single-component isotherms and binary breakthrough experiments, respectively. The uptake capacity of CHF3 was 1.03 mmol g–1 at 288 K and 7.0 bar. The selectivity of CHF3/N2 reaches 23–24 at 288 K and 3.0 bar, exhibiting a high separation selectivity. The pressure swing adsorption (PSA) simulation of treating the CHF3/N2-mixed gas with the actual exhaust gas composition was investigated. The results show that the purity of CHF3 can reach 99%, it can be used as a fire extinguishing agent under the optimized operating conditions, and the recovery rate is over 83%. Experimental studies show that SIFSIX-3-Ni has a good application prospect in the separation of CHF3/N2.