Highly selective separation of C3H6/C3H8 within hierarchical metal–organic CuxOy@HP–Cu–BTCs

Two critical characteristics for gas adsorption and separation are the porosity and open metal sites of adsorbents. The Cu–BTC (BTC = benzene–1,3,5–tricarboxylate) structure was tailored using a template synthesis technique to increase the separation performance for C 3 H 6 /C 3 H 8 mixtures. The three hierarchical porous frameworks, Cu x O y @HP–Cu–BTC, synthesized using a cationic surfactant (cetyltrimethylammonium bromide (CTAB)), a neutral organic amine (N,N–dimethyltetradecylamine (N,N)), and an anionic surfactant (sodium dodecylbenzene sulfonate (SDBS)) as the template, Cu x O y @HP–Cu–BTC(SDBS) exhibited the best performance, with a C 3 H 6 adsorption capacity of 6.679 mmol g −1 , which was significantly greater than that of C 3 H 8 (5.721 mmol g −1 ). Cu x O y @HP–Cu–BTC(SDBS) has an ideal ultra–microporous structure that encloses C 3 H 6 molecules precisely while rejecting slightly bigger C 3 H 8 molecules, and C 3 H 6 interacts strongly with unsaturated metal sites through particular π–Cu bonds. According to the ideal adsorbed solution theory (IAST), the adsorption selectivity of C 3 H 6 /C 3 H 8 was 63.322, which is more than that of the reference adsorbent Cu–BTC. Additionally, the breakthrough studies shown that Cu x O y @HP–Cu–BTC(SDBS) has a good dynamic performance for the effective separation of the C 3 H 6 /C 3 H 8 mixture.