Electric field-assisted preparation of aligned MWCNTs/polystyrene composite membranes for enhanced gas separation performance

doi:10.3969/j.issn.0438-1157.2014.01.044

Abstract

Abstract: Incorporation of particulate fillers in a membrane matrix has been proven effective in improving the separation performance of the membrane. This study explored the possibility of casting fillers embedded membranes with the assistance of alternating electric field to further improve the membrane performance in gas separation. Composite membranes with varying contents of multi-walled carbon nanotubes (MWCNTs) dispersed in polystyrene (PS) were prepared. In order to align the MWCNTs in the membrane, an alternating electric field of 2000 V·cm^-¹, 1 Hz was vertically applied on the pre-membrane solution until the solvent was evaporated completely. Electro-casting achieved not only vertical alignment but also more uniform dispersion of MWCNTs in the membrane matrix. The electro-cast composite membranes showed higher permeability of both carbon dioxide and methane, but the increment of the former was higher than the latter, resulting in improved selectivity of the membrane.

Key words: MWCNTs, composite membrane, electric field, align, separation, carbon dioxide, methane

摘要： 采用溶液浇铸法制备了不同含量多壁碳纳米管（MWCNTs）和聚苯乙烯（PS）掺杂的气体分离复合膜，成膜过程中在垂直于铸膜液平面的方向上施加场强为2000 V·cm^-1，频率为1 Hz的交变电场，直至溶剂挥发完全。采用荧光分光光度计、体式显微镜和数字万用表考察了膜的荧光特性，铸膜液中MWCNTs对水平电场的响应，MWCNTs在膜中的分散情况以及膜的垂直向电阻率，测定了复合膜对CO₂、CH₄的渗透系数。结果表明电场作用不仅可以实现MWCNTs在膜中的定向排布，还能够使MWCNTs在膜中分散得更均匀，定向复合膜CO₂和CH₄的透过性和选择性都优于非定向复合膜。

关键词: 碳纳米管, 复合膜, 电场, 定向, 分离, 二氧化碳, 甲烷

CLC Number:

TQ028.8

LI Xuewa, ZHAO Shixiong, WU Bin, AN De, WANG Yuxin. Electric field-assisted preparation of aligned MWCNTs/polystyrene composite membranes for enhanced gas separation performance[J]. CIESC Journal, 2014, 65(1): 337-345.

李雪娃, 赵世雄, 吴斌, 安德, 王宇新. 电场辅助制备多壁碳纳米管/聚苯乙烯复合膜的气体分离性能[J]. 化工学报, 2014, 65(1): 337-345.

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