Ethane selective adsorbent Ni(bdc)(ted)0.5 with high uptake and its significance in adsorption separation of ethane and ethylene

Abstract We reported a novel ethane selective metal–organic framework material Ni(bdc)(ted) 0.5 with a high uptake of C 2 H 6 and a decent selectivity towards C 2 H 6 /C 2 H 4 separation. This material was synthesized with double ligands (bdc and ted) by a hydrothermal method. Its C 2 H 6 and C 2 H 4 isotherms were subsequently measured. The BET surface area of the synthesized Ni(bdc)(ted) 0.5 reached 1701 m 2 /g. Successful assembling of the two organic ligands into Ni(bdc)(ted) 0.5 was indicated by FT-IR. TGA indicated that Ni(bdc)(ted) 0.5 was stable in the temperature region below 673 K. Ni(bdc)(ted) 0.5 exhibited decent adsorption capacities of C 2 H 6 and C 2 H 4 with a superior high C 2 H 6 adsorption capacity of 6.93 mmol/g at 100 kPa. More importantly, it exhibited preferential adsorption of C 2 H 6 over C 2 H 4 . Its C 2 H 6 /C 2 H 4 adsorption selectivity was in the range of 2–7.8 at pressure below 100 kPa, higher than the reported adsorbents possessing the characteristic of preferential adsorption of C 2 H 6 over C 2 H 4 . In addition, the isosteric heat of C 2 H 6 and C 2 H 4 adsorption on Ni(bdc)(ted) 0.5 were much lower compared to those π-complexation sorbents adsorbing olefin preferentially by binding with the π bond of olefin. The high ethane adsorption capacity, high ethane/ethylene selectivity and low isosteric heat of adsorption of Ni(bdc)(ted) 0.5 would make it a promising adsorbent for the effective separation of ethane/ethylene.