Preparation of UiO-66/DMBPTB and UiO-66-NH2/DMBPTB Nanocomposite Membranes with Enhanced CO2/CH4 Selectivity for Gas Separation

A great deal of fossil fuel is consumed due to enormous industrial and domestic activities. Meanwhile, massive emissions of CO2 have led to global warming. Replacing coal with natural gas will greatly decrease CO2 emissions. However, this requires cutting-edge technologies to purify CH4. Polymeric membranes with both high permeability and high selectivity are preferred but there exists a trade-off between them. To solve the problem, we incorporated the UiO-66 and UiO-66-NH2 metal organic frameworks (MOFs) nanoparticles into a Troger's base polymer, dimethylbiphenyl Troger's base polymer (DMBPTB). The CO2 permeability of the UiO-66/DMBPTB nanocomposite membranes increased by 13 folds with a marginal decrease in selectivity. Moreover, the composite membranes with amine-functionalized UiO-66 nanoparticles showed higher permeability and selectivity to the CO2/CH4 gas pair. The best gas separation performance was obtained for the composite membrane having 30 wt% UiO-66-NH2 nanoparticle, where the selectivity of CO2/CH4 was 18.0, and the CO2 permeability was 744 Barrer.