Facile Cu(I) Loading for Adsorptive C 3 H 6 / C 3 H 8 Separation Through Double Cu( II ) Salts Incorporation Within Pores With Unsaturated Fe( II ) Sites

Developing an effective adsorbent for olefin/paraffin separation is a crucial and challenging issue. We have developed an olefin-selective adsorbent by loading two different Cu(II) salts (CuCl2 and Cu(CH3COO)(2)) within an iron-based metal-organic framework (MOF) and reduced them to Cu(I) species without a high-temperature calcination and an external reducing agent. The successful development of Cu(I)-loaded MOFs was confirmed by characterizations including scanning electron microscope/energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, and Brunauer-Emmett-Teller analyses. From the comparisons between Cu(I)-loaded MOFs degassed at two different temperatures, we confirmed that the unsaturated Fe(II) sites within the iron-based MOF can enhance the stability of formed Cu(I) species and thus improve the C3H6/C3H8 selectivity. The resulted Cu(I)-loaded MOF shows large C3H6 uptake (5.15 mmol/g) and high C3H6/C3H8 selectivity (8.9) at 100 kPa and 293 K.