Hydrocarbon permeation properties through microporous fluorine-doped organosilica membranes with controlled pore sizes
Hydrocarbon permeation properties through microporous fluorine-doped organosilica membranes with controlled pore sizes
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DOI：
10.1016/j.memsci.2020.118787
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发表时间：
2021-02
影响因子：
9.5
通讯作者：
Mari Takenaka;Hiroki Nagasawa;T. Tsuru;M. Kanezashi
中科院分区：
文献类型：
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作者：
Mari Takenaka;Hiroki Nagasawa;T. Tsuru;M. Kanezashi
F-BTESM膜是通过将氟源掺杂到双（三乙氧基甲硅烷基）甲烷（BTESM）中来制备的，所述双（三乙氧基甲硅烷基）甲烷是由Si-CH 2-Si键组成的有机二氧化硅前体。采用单组分气体渗透和N2/C3-C4烃二元分离方法，研究了不同氟浓度下F-BTESM膜的孔径可控性和C3-C4烃渗透性能。有机硅膜的孔径可以通过掺杂适当浓度的氟来精确控制。当F/Si = 0.05时，膜的C3 H6/iso-C4 H8分离性能显著提高，在50 °C时膜的C3 H6/iso-C4 H8渗透比为388。烃类气体的渗透率随着孔径的扩大而增加，并且F-BTESM（F/Si = 0.15）显示出高水平的C3 H6渗透率（>5.0 × 10− 7 mol m−2s− 1 Pa −1）。碳氢化合物吸附和单渗透性能的结果表明，碳氢化合物的碳数和不饱和键的存在增强了对二氧化硅衍生材料的吸附亲和力。在N2/C3-C4烃的二元分离中，N2的渗透率与单一气体的渗透率相比显著降低，这是由于吸附在孔内的烃的阻塞效应。亲合力较强的烃类气体对N2的渗透有抑制作用。
F-BTESM membranes were fabricated by doping a fluorine source into bis(triethoxysilyl)methane (BTESM), which is an organosilica precursor composed of Si–CH2–Si bonds. Pore size controllability and C3–C4 hydrocarbon permeation properties for F-BTESM membranes with different concentrations of fluorine were evaluated using single-gas permeation and N2/C3–C4 hydrocarbon binary separation. The pore size of an organosilica membrane can be precisely controlled via doping with the correct concentration of fluorine. The molecular sieving properties for C3/C4 hydrocarbon separation such as that for C3H6/iso-C4H8was dramatically enhanced with the addition of a fluorine concentration of F/Si = 0.05, and this membrane showed a C3H6/iso-C4H8permeance ratio of 388 at 50 °C. The permeance of hydrocarbon gases was increased with an expansion of the pore size, and F-BTESM (F/Si = 0.15) showed a high level of C3H6permeance (>5.0 × 10−7mol m−2s−1Pa−1). The results of hydrocarbon adsorption and single permeation properties showed that the carbon number of the hydrocarbons and the presence of unsaturated bonds enhanced the adsorption affinity to silica-derived materials. In the binary separation of N2/C3–C4 hydrocarbons, N2permeance was remarkably decreased by comparison with single-gas permeation, which was due to a blocking effect by the hydrocarbons adsorbed inside the pores. Hydrocarbon gases with a stronger affinity tended to inhibit the permeation of N2.