CO2 capture under humid conditions in NH2-MIL-53(Al): the influence of the amine functional group

The hydrostable MIL-53(Al) and NH2-MIL-53(Al) CO2 capture properties were confirmed by kinetic uptake experiments, under different humidity conditions with maximum CO2 captures of approximately 6.0 wt% and 4.6 wt%, respectively, at 5% RH at 30 °C. In the case of MIL-53(Al) this corresponds to a 1.7-fold increase (CO2 capture) in comparison to anhydrous conditions. NH2-MIL-53(Al) exhibited a considerably stronger affinity to water than MIL-53(Al), and its ability to capture CO2, under humid conditions, was significantly reduced. The in situ FTIR experiments show how the hydrophobicity of the pores within MIL-53(Al) enhanced and sustained the CO2 adsorption capabilities of the material under more realistic CO2 capture conditions.