Fabrication of Zr-MOF filled PVA/CS blended membranes for high efficiency CO2 separation

Abstract

In the present work, a series of PVA and CS blend membranes were studied. These prepared membranes were evaluated by binary mixture gases of CO2/N2 and CO2/CH4. The optimum ratio of PVA/CS for CO2 permeance was achieved at 5:5. It recorded a CO2 permeability of 20.8 GPU (1 GPU = 1 × 10-6·cm3 (STP)·cm−2·s−1·cmHg−1) with CO2/N2 selectivity of 89.7, as well as CO2 permeability of 10.2 GPU and CO2/CH4 selectivity of 56.3. Secondly, two kinds of nanoparticle UiO-66 and UiO-66-NH2 were used to prepare mixed matrix membranes. The effects of nanofiller content and chemical groups on gas permselectivity were investigated. Results show that the addition of nanoparticles can effectively improve the permselectivity of membrane. The mixed matrix membranes addition with UiO-66-NH2 achieved the optimum CO2 performance and these were following the order of PVA(5)/CS(5)-UiO-66-NH2 > PVA(5)/CS(5)-UiO-66 > PVA(5)/CS(5). For all these membranes, the permeance and selectivity present initial increased and then decreased. Mixed matrix membranes addition UiO-66-NH2 (containing 3.75 wt%) exhibits a CO2 permeance of 32.77 GPU and CO2/N2 selectivity of 93.47, as well as CO2 permeance of 25.57 GPU and CO2/CH4 selectivity of 70.1, which was beyond the 2008 Robeson upper bound.