| Dendrimer membrane for COB2B separation is a new research subject in the field of gas membrane separation. Due to their unique physical and chemical properties such as large amount of terminal groups, highly branched molecular structure, small crystallizability, nonvolatility and good solubility, dendrimer membranes have the advantages of both stability and good permselectivity. In this paper, pentaerythrityl tetraethylenediamine (PETEDA), which would be used for a novel dendrimer membrane material, was successfully synthesized. Several methods of preparing membranes with this kind of dendrimer were investigated and PETEDA-PVA (polyvinylalcohol)/PES (polyethersulfone) blend composite membrane was successfully developed. The CO2/CH4permselectivity of this membrane was measured.PETEDA was synthesized through pentaerythrityl tetrabromide and ethylenediamine's reacting by the aminolyzing reaction of alkyl halide. It was proved that the product contains a lot of amino groups analyzed by FTIR (Fourier Transform Infrared Spectroscopy) and ETA (Elemental Analysis). Because amino groups are often viewed as facilitated transport carrers, it is possible that PETEDA membrane has good permselectivity of COB2B as facilitated transport membrane.PETEDA-PVA/PES (polyethersulfone) blend composite membrane was developed with the water solution of PETEDA and PVA as active layers and PES ultra-filtration membrane as the support. ESEM (Environmental Scanning Electron Microscope) was employed to characterize the morphology of the blend membrane. The results show that the active layer of the membrane, whose thickness is about 4μm, is dense and smooth. The permselectivities of the membrane were measured with pure CO2 and CH4 gas as well as binary mixture of CO2 and CH4. The results show that this composite membrane has good permselectivity. For pure feed gases, at feed gas pressure of 143.5 cmHg, the PETEDA-PVA blend membrane displays a CO2 permeation rate of 8.14×10-5cm3 (STP)cm-2s-1cmHg-1and CO2/CH4 ideal separation factor of 52. For mixed feed gas composed of 10 vol% CO2 and 90 vol% CH4, at feed gas pressure of 188.5 cmHg, the PETEDA-PVA blend membrane displays a COB2B permeation rate of 6.94×10-5P cm3 (STP)cm-2s-1cmHg-1and CO2/CH4 separation factor of 33. Furthermore, the effects of many kinds of factors such as... |
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