Enhancing ethane/ethylene separation performance through the amino-functionalization of ethane-selective MOF

The utilization of ethane-selective materials for adsorption-based separation technology presents an energy-efficient alternative to cryogenic distillation for ethylene (C2H4) purification from ethane (C2H6). To study the relations between separation performance and pore environments, we carried out the isoreticular chemistry rule to introduce the -NH2 groups into a C2H6-selective MOF [Cu1.5(BTC)(BPU)1.5(H2O)1.5], and successfully improved the adsorption capacity and selectivity for C2H6 over C2H4. The NH2-functionalized MOF [Cu1.5(NH2-BTC)(BPU)1.5(H2O)1.5] with a relatively narrow pore not only forms appropriate pore restriction but also provides additional binding sites to enhance the adsorption capacity of C2H6 relative to C2H4. Both gas adsorption and dynamic breakthrough results indicated that the -NH2 functionalization significantly enhanced the separation performance of materials for C2H6/C2H4 mixtures, allowing the production of C2H4 with a purity of over 99.99% and a productivity of up to 30.02 L/kg in one step. Theoretical calculations revealed that the synergistic effect of appropriate pore confinement and NH2-modified functional surfaces imposed stronger interactions on C2H6 than C2H4.