Influence of membrane skin morphology on CO2/N2 separation at sub-ambient temperatures
Influence of membrane skin morphology on CO2/N2 separation at sub-ambient temperatures
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DOI：
10.1016/j.memsci.2013.06.001
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发表时间：
2013-11
影响因子：
9.5
通讯作者：
Lu Liu;E. Sanders;J. Johnson;Oguz Karvan;S. S. Kulkarni-S.;David J. Hasse;W. Koros
中科院分区：
文献类型：
--
作者：
Lu Liu;E. Sanders;J. Johnson;Oguz Karvan;S. S. Kulkarni-S.;David J. Hasse;W. Koros
在253.15 K时，具有硅橡胶（PDMS）填充的熔融结节状选择性层的Matrimid®中空纤维膜比具有各向同性致密选择性层的中空纤维膜显示出更高的CO2/N2选择性和更高的CO2渗透性。成功地纺制了两种非对称中空纤维膜：具有熔融结节状表皮的纤维和具有真正致密表皮的纤维。皮肤形态用SEM图像证实。在253.15 ~ 308.15 K温度范围内对CO2/N2混合气体渗透性能进行了表征。渗透性能测试结果表明，在253.15 K下，经PDMS标准捻缝处理后，结皮纤维的CO2/N2选择性为90.5，CO2渗透率为63.3 GPU;而致密结皮纤维的CO2/N2选择性为52.5，CO2渗透率为16.6 GPU。PDMS捻缝对致密皮层纤维的影响很小，但对熔融的结节状皮层纤维有必要进行捻缝。提出了一个关于引入朗缪尔吸附位点和局部取向的聚合物链段的假设来解释更好的性能的捻缝结皮纤维。本工作为改进中空纤维膜脱除烟气中CO2提供了一种很有前途的方法。
Matrimid®hollow fiber membranes with silicone rubber (PDMS) calkedfused nodular selective layersdisplay much higher CO2/N2selectivity as well as higher CO2permeance than those withisotropic dense selective layersat 253.15 K. Two kinds of asymmetric hollow fiber membranes were successfully spun: fibers with fused nodular skins and fibers with truly dense skins. The skin morphologies were confirmed with SEM images. CO2/N2mixed gas permeation characterization was carried out within the temperature range of 253.15 K to 308.15 K. Permeation results showed that, at 253.15 K, the nodular-skinned fibers displayed CO2/N2selectivity of 90.5, and CO2permeance of 63.3 GPU after standard PDMS calking; while the dense-skinned fibers displayed CO2/N2selectivity of 52.5, and CO2permeance of 16.6 GPU. The PDMS calking had negligible effect on the dense-skinned fibers, but it was necessary for the fused nodular-skinned fibers. A hypothesis regarding the introduction of Langmuir sorption sites and a local orientation of polymer chain segments is proposed to explain the better performance of the calked nodular-skinned fibers. This work provides a promising method for improved hollow fiber membranes for the removal of CO2from flue gas.