Abstract
Iron metal–organic framework, MIL-100(Fe) was prepared by a hydrothermal method and used as a support to incorporate diethylenetriamine (DETA) for the study of CO
2
adsorption and separation of CO
2
/N
2
. All synthesized adsorbents were characterized by PXRD, N
2
adsorption–desorption isotherms, FT-IR, TGA, SEM, and elemental analysis. Structural characterization results have revealed that the structure of MIL-100(Fe) was not changed by the incorporation of diethylenetriamine. The CO
2
adsorption capacities were 29 cm
3
g
−1
and 41 cm
3
g
−1
at 298 K, 1 bar for MIL-100(Fe) and DETA–MIL-100(Fe), respectively. Adsorption of CO
2
on DETA–MIL-100(Fe) was higher than that on MIL-100(Fe). The enhancement was due to the presence of amine groups which could form ammonium carbamate by interaction with CO
2
. Similarly, the N
2
adsorption capacities were 3 cm
3
g
−1
and 0.9 cm
3
g
−1
at 298 K, 1 bar for MIL-100(Fe) and DETA–MIL-100(Fe), respectively. The decrease in N
2
adsorption capacity was due to the decrease in surface area. The selectivity of CO
2
/N
2
on DETA–MIL-100(Fe) was four times higher than that on MIL-100(Fe). The heat of CO
2
adsorption was 74.2 kJ mol
−1
at low coverage of CO
2
on DETA–MIL-100(Fe) and the CO
2
adsorption capacity was constant in each adsorption cycle over the same adsorbent.