Rapid mechanochemical construction of HKUST-1 with enhancing water stability by hybrid ligands assembly strategy for efficient adsorption of SF6

Sulfur hexafluoride (SF6) is commonly used as an insulating medium for high-voltage electrical equipment. However, SF6 is also a greenhouse gas, which escapes into the atmosphere during use, so its emissions represent a serious environmental threat. Therefore, the capture and recovery of SF6 gas are processes of great significance. Herein, we present a straightforward method for the rapid mechanochemical synthesis of a series of HKUST-1 that can be utilized for the efficient adsorption of SF6. Using trimesic acid (H3BTC) and copper nitrate as starting materials, [email protected] (X = Im, Trtz, or Tetz) was successfully prepared by doping three different hybrid ligands of imidazole (Im), 1,2,4-1H-triazole (Trtz), and tetrazole (Tetz), respectively. After the introduction of the mentioned hybrid ligands, the porosity of HKUST-1 was observed to be retained, but its ability to adsorb SF6 was reduced slightly. Notably, the water stability of imidazole-doped [email protected] was significantly enhanced with respect to that of HKUST-1. The results of adsorption experiments indicate that Im1%@HKUST-1 has a superior SF6 adsorption of 5.98 mmol·g−1 at 1 bar and 25 °C, as well as an excellent SF6/N2 selectivity with up to 93 at 1 bar, which is significantly higher than that reported in the literature for most SF6 adsorbents. Therefore, by implementing the hereby-developed rapid mechanochemical construction of HKUST-1 by hybrid ligand assembly strategy, one may not only effectively improve the water stability of HKUST-1 but also avoid the lengthy process and harsh preparation conditions involved in the traditional hydrothermal synthesis, providing an important reference for the preparation of metal–organic frameworks (MOFs) and their application to gas separation.