Highly CO selective Cu(I)-doped MIL-100(Fe) adsorbent with high CO/CO2 selectivity due to π complexation: Effects of Cu(I) loading and activation temperature

• Published in: Microporous and mesoporous materials 2019-01, Vol.274, p.17-24
• Main Authors: Vo, The Ky, Bae, Youn-Sang, Chang, Bong-Jun, Moon, Su-Young, Kim, Jeong-Hoon, Kim, Jinsoo
• Format: Article
• Language: English
• Subjects: Adsorbent; CO2; Copper; Metal-organic frameworks (MOFs); MIL-100(Fe)
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2018.07.024

Cu(I) doping of octahedral MIL-100(Fe) was successfully performed by means of impregnation and consequent reduction under vacuum conditions. Although MIL-100(Fe) adsorbed CO2 better than CO, Cu(I)@MIL-100(Fe) showed selective CO adsorption compared to CO2 owing to π complexation between CO and Cu(I). Effects of Cu(I) loading concentration, activation temperature, and adsorption temperature upon CO/CO2 adsorption properties were systematically investigated. The adsorption behaviors of CO and CO2 on MIL-100(Fe) and Cu(I)@MIL-100(Fe) were well described by the dual-site Langmuir–Freundlich (DSLF) model. Ideal adsorbed solution theory (IAST) was used to predict adsorption isotherms of equimolar CO and CO2 mixtures and to predict CO/CO2 selectivities as a function of bulk pressure. The obtained results showed that 45 wt% Cu(I)-doped MIL-100(Fe) had CO adsorption capacity of 3.10 mmol g−1 and CO/CO2 selectivity of 420 at 298 K and 1 bar. In addition, a large CO working capacity of 1.39 mmol g−1 was observed for 45 wt% Cu(I)-doped MIL-100(Fe) in the pressure range of 10–100 kPa. Cu(I)-doped MIL-100(Fe) thus appears promising as an adsorbent material for effective CO/CO2 separation. [Display omitted] •Cu(I) was doped onto MIL-100(Fe) for highly selective adsorption of CO compared to CO2.•The effects of metal loading, activation temperature, and adsorption temperature were investigated.•Cu(I)@MIL-100(Fe) exhibited the high CO adsorption capacity of 3.10 mmol g−1.•The IAST prediction of CO/CO2 selectivity was 420 at 298 K and 1 bar.•The CO working capacity of 1.39 mmol g−1 was obtained for 45Cu(I)@MIL-100(Fe).