School of Environmental Science and Engineering, Sun Yat-sen University , Guangzhou 510006, China.
Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University , Guangzhou 510275, China.
Environ Sci Technol. 2017 Dec 19;51(24):14342-14351. doi: 10.1021/acs.est.7b03952. Epub 2017 Nov 28.
A clear understanding of membrane aging process is essential for the optimization of chemical cleaning in membrane-based facilities. In this study, two-dimensional (2D) Fourier transformation infrared (FTIR) correlation spectroscopy (CoS) analysis was first used to decipher the sequential order of functional group changes of NaOCl-aged poly(ether sulfone)/polyvinylpyrrolidone (PES/PVP) membranes. The synchronous maps showed 12 major autopeaks in total. Based on the asynchronous maps, a similar aging sequence of membrane groups was clearly identified at three pHs (i.e., 6, 8, and 10): 1463, 1440, and 1410 (cyclic C-H structures) > 1662 (amide groups) > 1700 (succinimide groups) > 1320, 1292 (S═O asymmetric) > 1486, 1580 (aromatic structures) > 1241 (aromatic ether bands) > 1105, 1150 cm (O═S═O symmetric). Among them, membrane chlorination occurred at 1241, 1410, and 1440 cm. Moreover, the initial degradation of PVP and the subsequent transformation of PES could be highly responsible for the increased water permeability and the enlargement of membrane pores, respectively, both leading to serious fouling with humic acid filtration. In summary, the 2D-FTIR-CoS analysis is a powerful approach to reveal the interaction mechanisms of NaOCl-membrane and could be also useful to probe the process of membrane fouling and chemical cleaning.
清楚了解膜老化过程对于优化基于膜的设施中的化学清洗至关重要。在这项研究中，首先使用二维（2D）傅里叶变换红外（FTIR）相关光谱（CoS）分析来解析次氯酸钠老化的聚（醚砜）/聚乙烯吡咯烷酮（PES/PVP）膜的官能团变化的顺序。同步图谱总共显示了 12 个主要的自峰。根据异步图谱，在三个 pH 值（即 6、8 和 10）下清楚地确定了膜基团的相似老化顺序：1463、1440 和 1410（环状 C-H 结构）>1662（酰胺基团）>1700（琥珀酰亚胺基团）>1320、1292（S═O 不对称）>1486、1580（芳构结构）>1241（芳族醚带）>1105、1150 cm（O═S═O 对称）。其中，膜氯化发生在 1241、1410 和 1440 cm 处。此外，PVP 的初始降解和随后的 PES 转化可能是导致水透过率增加和膜孔扩大的主要原因，这两者都会导致严重的腐殖酸过滤污染。总之，2D-FTIR-CoS 分析是一种揭示 NaOCl-膜相互作用机制的有力方法，也可用于探测膜污染和化学清洗过程。
