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Degradation of full aromatic polyamide NF membrane by sulfuric acid and hydrogen halides: Change of the surface/permeability properties
Polymer Degradation and Stability ( IF 6.3 ) Pub Date : 2019-02-10 , DOI: 10.1016/j.polymdegradstab.2019.02.008
Byung-Moon Jun , Hyung Kae Lee , You-In Park , Young-Nam Kwon

We investigated the effects of both sulfuric acid (pH 0 to 2) and hydrogen halides (pH 0) on the physical, chemical, and performance properties of full aromatic nanofiltration (NF) polyamide (PA) NE90 membrane. Surface characterizations of the degraded membranes were conducted by Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), goniometer, and zeta potential analyzer. No noticeable changes were observed in the surface properties of the membrane exposed to sulfuric acid; however, the permeable characteristics were changed due to the distortion of hydrogen bonding from additionally generated proton bridge for O-protonation and the formation of tetrahedral structure for N-protonation. On the other hand, the membrane's physico-chemical properties were much affected by hydrogen halides compared with sulfuric acid. Amide peaks N-H bending at 1541 cm−1 and C=O stretching at 1663 cm−1 in ATR-FTIR were reduced because of the reaction of the PA with halogens produced by oxidation of hydrogen halides. Molecular halogen gases (Cl2, Br2, I2) generated in the reaction bottle were also analyzed by GC/MS during exposure of the membrane to various types of acids. The increment in halogenation on PA was in the order HCI, HBr, and HI, and it was the same as the order of temporary dipole moment from the effect of molecular size. Water flux after exposure to hydrogen halides was severely decreased due to broken hydrogen bonding by halogenation. Investigation of sulfuric acid and hydrogen halides on the change of the physico-chemical characteristics in the NE90 can be utilized when full aromatic NF membrane is applied to treat/recycle several industrial processes, which include sulfuric acid or hydrogen halides.



中文翻译:

硫酸和卤化氢降解全芳族聚酰胺NF膜:表面/渗透性的变化

我们研究了硫酸(pH 0至2)和卤化氢(pH 0)对全芳族纳米过滤(NF)聚酰胺(PA)NE90膜的物理,化学和性能特性的影响。降解膜的表面表征通过扫描电子显微镜(SEM),衰减全反射傅里叶变换红外光谱(ATR-FTIR),X射线光电子能谱(XPS),测角计和Zeta电位分析仪进行。暴露于硫酸的膜的表面性能未观察到明显变化;然而,渗透性由于改变了另外产生的用于O质子化的质子桥和形成用于N质子化的四面体结构的氢键的结合而发生了变化。另一方面,膜' 与硫酸相比,卤化氢对其物理化学性质的影响更大。酰胺峰NH在1541 cm处弯曲由于PA与卤化氢氧化产生的卤素反应,降低了在ATR-FTIR中在1663 cm -1处拉伸的-1和C = O。分子卤素气体(Cl 2,Br 2,I 2在膜暴露于各种酸的过程中,还通过GC / MS分析了反应瓶中生成的)。PA上卤化的增加顺序为HCI,HBr和HI,并且从分子大小的影响来看,它与临时偶极矩的顺序相同。由于卤化破坏了氢键,暴露于卤化氢后的水通量大大降低。当使用全芳族NF膜处理/回收包括硫酸或卤化氢在内的多种工业过程时,可以利用NE90中的硫酸和卤化氢对理化特性变化的研究。

更新日期:2019-02-10
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