a) CO2 and CH4 permeation properties measured for a 1:1 CO2/CH4 mixture at 298 K and Δp = 3 bar of MMMs comprising 6FDA-DAM and NH2 MIL 53(Al) MOF nanoparticles as a function of the filler loading, influence of the trans-membrane pressure difference (Δp = 3, 6 and 9 bar), b) on the CO2 permeability and c) on the selectivity of the NH2 MIL 53(Al)@6FDA-DAM MMMs as a function of filler loading. The data are average values of at least two membranes and error bars correspond to standard deviation. ☆ bare 6FDA-DAM and ● 5 wt%, ▲ 10 wt%, ◊ 15 wt% and ■ 20 wt% NH2-MIL-53(Al)@6FDA-DAM MMMs, respectively.