Chemical alteration of LDPE hollow fibers exposed to monoethanolamine solutions used as absorbent for CO2 capture process
Chemical alteration of LDPE hollow fibers exposed to monoethanolamine solutions used as absorbent for CO2 capture process
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DOI：
10.1016/j.seppur.2011.05.017
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发表时间：
2011-07
影响因子：
8.6
通讯作者：
S. Sedghi;J. Brisson;D. Rodrigue;M. Iliuta
中科院分区：
文献类型：
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作者：
S. Sedghi;J. Brisson;D. Rodrigue;M. Iliuta
研究了单乙醇胺（MEA）对膜接触器用无孔低密度聚乙烯（LDPE）中空纤维表面的影响。LDPE中空纤维与MEA溶液（新鲜（未加载）或CO2加载后）在不同温度和溶液pH下保持接触8至45天的时间长度。进行FT-IR、XPS和接触角分析以监测膜表面上的化学变化。在使纤维与未加载的MEA溶液接触延长的时间（超过8天）并用水彻底洗涤样品后，XPS分析显示中空纤维的氧和氮含量增加。此外，FT-IR光谱显示LDPE中空纤维表面存在羰基和酰胺基团。这些基团被发现在更高的温度下更显着的数量。这表明LDPE中空纤维发生氧化降解。MEA与LDPE表面氧化产生的羰基之间的反应可能导致酰胺基团的形成。另一方面，接触角测量表明，中空纤维的疏水性降低，作为其表面能的增加的结果，这可以降低膜接触器中的膜的长期稳定性。然而，基于FT-IR和接触角测量，LDPE化学降解被认为是不太重要的CO2的存在下，由于负载MEA溶液的pH值的降低，导致膜的疏水性能的变化慢得多。
The effect of monoethanolamine (MEA) on the surface of non-porous low density polyethylene (LDPE) hollow fibers aimed to be used in membrane contactors was investigated. LDPE hollow fibers were kept in contact with MEA solution (fresh (unloaded) or after CO2loading) for lengths of time varying from 8 to 45days, at different temperatures and solution pH. FT-IR, XPS and contact angle analyses were performed in order to monitor chemical changes on the membrane surface. After keeping the fibers in contact with unloaded MEA solutions for prolonged time (more than 8days) and thoroughly washing the samples with water, XPS analysis showed an increase in oxygen and nitrogen content of hollow fibers. In addition, FT-IR spectra showed the presence of carbonyl and amide groups on the LDPE hollow fiber surface. These groups were found to be in more significant quantity at higher temperatures. It is suggested that the LDPE hollow fibers undergo oxidative degradation. The reaction between MEA and carbonyl groups generated by oxidation on the LDPE surface might lead to the formation of amide groups. On the other hand, contact angle measurements showed that the hydrophobicity of hollow fibers decreased as the result of the increase in their surface energy, which can reduce the long-term stability of membranes in membrane contactors. However, based on both FT-IR and contact angle measurements, LDPE chemical degradation was found to be less important in the presence of CO2due to the reduction of the pH of loaded MEA solutions, leading to a much slower alteration of the membrane hydrophobic properties.