Pillar-layer Zn–triazolate–dicarboxylate frameworks with a customized pore structure for efficient ethylene purification from ethylene/ethane/acetylene ternary mixtures

The selective adsorption of C(2)H(6) and C(2)H(2) over C(2)H(4) from C(2)H(2)/C(2)H(4)/C(2)H(6) ternary mixtures for one-step C(2)H(4) purification represents a crucial yet challenging task in industry. The pore structure of the adsorbents must be finely tailored to meet the demanding requirements for the separation considering the very similar physicochemical properties of the three gases. Herein, we report a Zn–triazolate–dicarboxylate framework, HIAM-210, featuring a novel topology which possesses one-dimensional channels decorated with adjacent uncoordinated carboxylate–O atoms. The suitable pore size and customized pore environment enable the compound to selectively capture C(2)H(6) and C(2)H(2) with high C(2)H(2)/C(2)H(4) and C(2)H(6)/C(2)H(4) selectivities of both 2.0. Breakthrough experiments show that polymer-grade C(2)H(4) can be directly harvested from C(2)H(2)/C(2)H(4)/C(2)H(6) (34/33/33 and 1/90/9) ternary mixtures. The underlying mechanism of the preferential adsorption was uncovered by grand canonical Monte Carlo simulations and DFT calculations.