Zhihua Qiao

Gas separation membrane with CO2-facilitated transport highway constructed from amino carrier containing nanorods and macromolecules

The CO2-facilitated transport highway in the membrane was designed through amino carrier containing polyaniline nanorods and polyvinylamine. CO2 molecules could transfer quickly owing to the reversible reaction with amino groups. This strategy may have great inspiration for constructing ideal membrane structure and offering the possibility to fabricate highly permeable and selective membrane.

Fabrication of high-performance facilitated transport membranes for CO2 separation

At present, liquid membranes, ion-exchange membranes and fixed carrier membranes are the three popular facilitated transport membranes for CO2 separation. They possess their own advantages, as well as their respective deficiencies. In view of the characters of these three types of facilitated transport membrane, we report a method to combine their advantages and overcome their deficiencies. A new membrane was fabricated by establishing high-speed facilitated transport channels in the fixed carrier membrane. This membrane displays excellent CO2 separation performance and good stability. The results suggest that this is an effective way to fabricate high performance and high stability CO2 separation membranes. Furthermore, establishing high-speed facilitated transport channels in fixed carrier membranes will be a universal route to improve the performance of gas separation membranes.

A Highly Permeable Aligned Montmorillonite Mixed-Matrix Membrane for CO2 Separation.

Highly permeable montmorillonite layers bonded and aligned with the chain stretching orientation of polyvinylamineacid are immobilized onto a porous polysulfone substrate to fabricate aligned montmorillonite/polysulfone mixed-matrix membranes for CO2 separation. High-speed gas-transport channels are formed by the aligned interlayer gaps of the modified montmorillonite, through which CO2 transport primarily occurs. High CO2 permeance of about 800 GPU is achieved combined with a high mixed-gas selectivity for CO2 that is stable over a period of 600 h and independent of the water content in the feed.

CO2 separation enhancement of the membrane by modifying the polymer with a small molecule containing amine and ester groups

A novel composite membrane was developed by using a polymer modified by a small molecule containing amine and ester groups as the active layer. The composite membrane shows high selectivity as well as high CO2 permeance for different CO2/gas mixtures.

High adsorption performance polymers modified by small molecules containing functional groups for CO2 separation

We proposed the novel idea of using small molecules with functional groups to modify the functional groups and molecular aggregation of a polymer simultaneously. Small molecular amine-modified PVAm samples were prepared as novel adsorbents that have high CO2 adsorption performance and good stability.

In situ synthesis of polymer grafted ZIFs and application in mixed matrix membrane for CO2 separation

Mixed matrix membranes (MMMs) provide an efficient implementation that overcomes the bottleneck of individual inorganic or polymeric membranes for gas separation, but still face challenges. Here, we put forward a strategy of using in situ synthesized polymer grafted metal organic frameworks (MOFs) to eliminate both interfacial and carrier problems existing in the MMMs. Specifically, polyethyleneimine (PEI) grafted ZIF-8 (PEI-g-ZIF-8) was synthesized in situ by using Zn2+, 2-methylimidazole, and hyperbranched PEI through a rapid method at room-temperature. The chemical composition and porous structure of PEI-g-ZIF-8 were investigated by Fourier transform infrared spectroscopy, powder X-ray diffraction, N2 adsorption–desorption measurement, etc. The results indicated that the synthesized PEI-g-ZIF-8 achieves an enlarged pore volume and aminated surface. The improved interfacial compatibility between PEI-g-ZIF-8 nanoparticles and poly(vinylamine) (PVAm) was confirmed through high-sensitivity differential scanning calorimetry and zeta potential measurements. According to the CO2/gas separation tests, the MMMs incorporating with PEI-g-ZIF-8 achieved 1990 GPU of CO2 permeance and 79.9 of selectivity for CO2/N2 (15/85 vol%) separation, and 1790 GPU of CO2 permeance and 40.7 of selectivity for CO2/CH4 (10/90 vol%) separation, under 0.30 MPa gas pressure.