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[Display omitted] • We verified for the first time that Cu(I) has strong interaction with ST. • Cu(M)@MIL-100(Fe) exhibits the highest ST/EB selectivity and the largest ST uptake. • Cu(M)@MIL-100(Fe) shows good cyclic adsorption and desorption performance. • Cu(I) incorporation could open a new way to develop ST-selective adsorbents. Developing styrene (ST) selective adsorbents is an important issue in the petrochemical industry because ST is a crucial precursor for many useful materials. Since ST often presents as mixtures containing ethylbenzene (EB), an effective adsorbent having high ST selectivity over EB, large ST adsorption capacity, and good repeated adsorption/desorption is needed. We hypothesized that Cu(I) ions could provide a special ST selectivity due to unsaturated π-orbitals in ST. We have successfully loaded Cu(I) ions within a mesoporous metal–organic framework (MOF) by using redox-active Fe(II) sites in the MOF. By control experiments for the MOFs with and without Cu(I) ions, we verified for the first time that Cu(I) ions have strong ST selectivity over EB. The Cu(I)-loaded MOF (Cu(M)@MIL-100(Fe)) shows the largest ST uptakes and the highest ST/EB selectivity among the reported values for MOF adsorbents. Additionally, Cu(M)@MIL-100(Fe) maintains its good performance for several cycles. These indicate that Cu(M)@MIL-100(Fe) is a prospective adsorbent for ST/EB separation. We believe this Cu(I) incorporation strategy could open a new way to develop styrene selective adsorbents. [ABSTRACT FROM AUTHOR]

• Effect of different unsaturated metal ions (M2+) on ST/EB separation was studied. • Co-MOF-74 exhibited the highest ST/EB selectivity and the largest ST uptakes. • The obtained selectivity and uptake are superior to those of benchmark materials. • The high selectivity is attributed to preferential interaction between Co2+ and ST. • Co-MOF-74 retains its performance for three adsorption/desorption cycles. Styrene (ST) is one of the most important feedstocks in the petrochemical industry and must be separated from a mixture of ST and ethylbenzene (EB). While the current technology comprises the energy-intensive vacuum distillation process, energy-saving adsorptive separation can be an alternative for ST/EB separation. The potential of a series of isostructural metal-organic frameworks (MOFs), M-MOF-74 (M = Mg, Co, Cu, or Zn), featured by highly dense unsaturated metal sites were evaluated for use in ST/EB separation using liquid-phase adsorption experiments. While all four M-MOF-74 materials showed selective adsorption of ST over EB, Co-MOF-74 exhibited the highest ST/EB selectivity (6.9) and the largest ST uptake (2.5 mmol/g), which were superior to those of benchmark MOF materials. This can be explained by the preferential interaction between unsaturated Co2+ sites and unsaturated ST molecules. Moreover, Co-MOF-74 retained its adsorption performance, porosity, and structural integrity after three consecutive adsorption and desorption experiments. These findings suggest that creating high density of Co2+ sites within a proper pore size would be an efficient strategy for developing an adsorbent for ST/EB separation. [ABSTRACT FROM AUTHOR]

Highlights • The potential of MIL-53(Al) for a brand-new LNG-ANG system was evaluated. • Deliverable capacities of HKUST-1 and Norit RB3 were compared. • GCMC simulations provided a reason for high deliverable capacity of MIL-53(Al). • The stability of MIL-53(Al) during 5 cycles of temperature swings was tested. Abstract Natural gas (NG) is the most eco-friendly hydrocarbon fuel. However, due to its low energy density at ambient temperature and pressure, it is currently used restrictively. Recently, the coupling of liquefied natural gas (LNG) regasification and the adsorbed natural gas (ANG) charging processes has been suggested as a possible solution for expanding the uses of NG. Although metal-organic frameworks (MOFs) have been widely studied for ANG systems, few studies have been conducted on LNG-ANG systems. We evaluated the potential of MIL-53(Al) for LNG-ANG and compared it with HKUST-1 and Norit RB3. MIL-53(Al) exhibited a significantly larger deliverable capacity (262.3 v(STP)/v), which is almost close to the deliverable methane capacity target. GCMC simulations suggest that MIL-53(Al) may be transformed to a more favorable structure for methane adsorption at 159 K. Even with this flexible behavior, MIL-53(Al) was stable under repeated temperature swings between cryogenic and room temperatures. We believe that this flexible behavior of MIL-53(Al) could be applied to other gas storage and separations. [ABSTRACT FROM AUTHOR]

A hydrothermally stable, zirconium-based metal–organic framework called UiO-66-Zr has been studied for its ability to separate SF 6 from SF 6 /N 2 mixtures. The ideal adsorbed solution theory (IAST)-predicted selectivities based on single-component isotherms and the dynamic breakthrough calculations for mixture conditions demonstrate that UiO-66-Zr can effectively separate SF 6 /N 2 mixtures. Remarkably, UiO-66-Zr exhibits the highest SF 6 /N 2 selectivity values ever reported. In comparison with zeolite-13X, which is a benchmark adsorbent, UiO-66-Zr clearly shows enhanced separation performance, especially for the diluted SF 6 concentration. Moreover, UiO-66-Zr maintains its adsorption capacity even after one month of storage under ambient conditions. UiO-66-Zr may be considered as a promising adsorbent for SF 6 /N 2 separations. [ABSTRACT FROM AUTHOR]