电子级 CF₄中痕量 NF₃杂质的吸附脱除

The efficient and low-cost removal of trace NF₃ impurities in the preparation of CF₄ by fluorocarbon synthesis method has important application value for the development of electronic grade CF₄. In this paper, a series of MOF-74 materials with high density open metal sites were prepared as adsorbents. Based on the strong interaction of active sites on NF₃ inside the one-dimensional channels, the ultra-high adsorption capacity of NF₃ under low partial pressure (up to 50.3mL/g at 298K and 10kPa) and excellent NF₃/CF₄ selectivity (the IAST selectivity of MOF-74-Mg can reach to 245.6 at 0.001 molar ratio of NF₃) were achieved. The theoretical results showed that the unsaturated metal sites in the pores of MOF-74 had stronger affinity for the polar molecule NF₃, and the fixed-bed breakthrough experiment further verified that the materials could capture trace NF₃ in CF₄ under dynamic conditions. In summary, the above results confirmed that MOFs materials with open metal sites could be served as an efficient and economical adsorbent, providing a new strategy for the separation and purification of trace NF₃ impurities in CF₄ prepared by fluorocarbon synthesis.