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

Abstract

The selective adsorption of C₂H₆ and C₂H₂ over C₂H₄ from C₂H₂/C₂H₄/C₂H₆ ternary mixtures for one-step C₂H₄ 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 C₂H₆ and C₂H₂ with high C₂H₂/C₂H₄ and C₂H₆/C₂H₄ selectivities of both 2.0. Breakthrough experiments show that polymer-grade C₂H₄ can be directly harvested from C₂H₂/C₂H₄/C₂H₆ (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.