The gutter layer of thin film composite membranes (TFCMs) promotes the formation of ultrathin top layers. MOFs nanosheets gutter layer is an efficient strategy for building gas separation TFCMs while suffers from such an issue that gas molecules transport between interlayer thus making it difficult to fully utilize the excellent molecule sieving ability of MOFs. In this work, both MOFs nanosheets and continuous MOFs gutter layers were constructed to prepare TFCMs for CO 2 separation. The polyamide top layer with irregular structure was formed on MOFs gutter layer by interfacial polymerization. The physical and chemical properties as well as separation performance of different TFCMs were further compared. Benefitting from the denser structure and stronger hydrophobicity of continuous ZIF-8 gutter layer, the obtained top layer showed more regular structure with ultrathin thickness (≈30 nm). At the same time, due to the ZIF-8 gutter layer provided additional and stable CO 2 selectivity, the CO 2 permeance reached 588.2 GPU with the selectivity of CO 2 /N 2 and CO 2 /CH 4 of 49.8 and 52.3, which surpassed the 2008 Robeson upper bound. We believe that such a membrane design based on continuous MOFs gutter layers is a promising approach for high-performance gas separation membranes.
An imidazolium ionic liquid (1-aminoethyl-3-methylimidazolium bromide, AMIB) was exploited to prepare thin film composite membranes (TFCMs) exhibiting high water permeability, salt rejection, antibiotics separation and antibacterial properties. Polyamide TFCMs were prepared by “piperzine ~ trimesoyl chloride” (PIP-TMC) interfacial polymerization. AMIB molecules were anchored to membrane surface through “acyl chloride ~ amine” amidation. Salt rejection and water flux of the modified membrane (PIP-TMC-AMIB) was 95 ± 1% (R Na2SO4 ) and 135 ± 5 L m −2 h −1 at 6 bar pressure. Thus the permeance of the modified TFCM is ~ 4 times as high as that of lab-made pristine PIP-TMC TFCM. The PIP-TMC-AMIB membrane shows high water permeance (~ 25 Lm −2 h −1 bar) and effective rejection (>90%) toward antibiotics such as 50 ppm ciprofloxacin, tetracycline, oxytetracycline, levofloxacin and erythrocin. In addition, the membrane exhibits effective separation of antibiotics/sodium chloride mixtures, and highly improved antibacterial properties by killing 99% E. coli colonies.
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