Figure 6. Application of the MOF-polymer composites in a gas separation process.

Separation selectivity, defined as the ratio between the permeability of CO₂ and CH₄, as a function of the pressure difference over the membrane for the MOF-polymer composites when employed as membranes in the separation of CO₂ from an equimolar CO₂/CH₄ mixture at 298 K. For comparison purposes, results for a neat polyimide membrane (PI) are also presented. The data correspond to steady operation conditions, after at least 8 hours on stream. CO₂ permeabilities spanned in the range of 2.8-5.8 Barrer, while CH₄ permeabilities were lower than 0.3 Barrer in all cases (see Supplementary Table S1). 1 Barrer = 10⁻¹⁰ cm³ (STP) cm⁻¹ s⁻¹ cmHg⁻¹. Error bars correspond to the standard deviations, as determined from three independent tests with selected membranes. When not displayed, error bars are smaller than the symbols.