溶解度
吸附
选择性
聚酰亚胺
膜
热扩散率
扩散
磁导率
甲烷
渗透
气体扩散
气体分离
促进扩散
分配系数
稀释
化学
化学工程
分析化学(期刊)
热力学
色谱法
物理化学
有机化学
生物化学
图层(电子)
催化作用
吸附
工程类
物理
电极
作者
Giuseppe Genduso,Bader S. Ghanem,Ingo Pinnau
出处
期刊:Membranes
[MDPI AG]
日期:2019-01-08
卷期号:9 (1): 10-10
被引量:52
标识
DOI:10.3390/membranes9010010
摘要
The nonideal behavior of polymeric membranes during separation of gas mixtures can be quantified via the solution-diffusion theory from experimental mixed-gas solubility and permeability coefficients. In this study, CO2-CH4 mixtures were sorbed at 35 °C in 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA)-m-phenylenediamine (mPDA)—a polyimide of remarkable performance. The existence of a linear trend for all data of mixed-gas CO2 versus CH4 solubility coefficients—regardless of mixture concentration—was observed for 6FDA-mPDA and other polymeric films; the slope of this trend was identified as the ratio of gas solubilities at infinite dilution. The CO2/CH4 mixed-gas solubility selectivity of 6FDA-mPDA and previously reported polymers was higher than the equimolar pure-gas value and increased with pressure from the infinite dilution value. The analysis of CO2-CH4 mixed-gas concentration-averaged effective diffusion coefficients of equimolar feeds showed that CO2 diffusivity was not affected by CH4. Our data indicate that the decrease of CO2/CH4 mixed-gas diffusion, and permeability selectivity from the pure-gas values, resulted from an increase in the methane diffusion coefficient in mixtures. This effect was the result of an alteration of the size sieving properties of 6FDA-mPDA as a consequence of CO2 presence in the 6FDA-mPDA film matrix.
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