Regulation of the nature and sites of copper species in CuNaY zeolites for ethylene and ethane separation

Abstract

Y-zeolites modified with copper ions (CuY) are adsorbents with great potential and economic value for the adsorption and separation of ethylene and ethane. However, there are still some problems that need to be solved, such as the relationship between the states of Cu species and the ethylene adsorption capacity. In this study, a series of CuNaY adsorbents with different loadings was prepared by a liquid phase ion exchange method. The Cu(I)NaY-3 adsorbent showed the most significant ethylene breakthrough adsorption capacity (2.14 mmol g⁻¹). The location, valence, and dispersion of copper species in the CuNaY zeolites were comprehensively analysed by H₂-TPR, in situ FTIR, HRTEM and XPS techniques. The experiments indicated that the adsorption capacity of ethylene depends on the states of the Cu species, which was also confirmed by DFT. These results can serve as a theoretical foundation and guideline for the development of highly efficient Cu-modified zeolite adsorbents for ethylene separation.