Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
Anal Chem. 2011 Mar 1;83(5):1709-16. doi: 10.1021/ac102891g. Epub 2011 Feb 3.
Membrane fouling is the major drawback of membrane-based technologies because it will lead to severe flux declines and the need to clean or replace the fouled membrane. A technique capable of early diagnosis, process monitoring, and evaluation of the role of different foulants playing in the fouling process is crucial for the fouling control. We develop surface-enhanced Raman spectroscopy (SERS) as a new and versatile tool to investigate the fouling process of protein on PVDF (polyvinylidene fluoride) membranes as well as the fouling propensity of three different proteins. We optimized the aggregation level and volume of SERS-active Ag sol and the spectra acquisition method combined with a statistical analysis method to ensure a high detection sensitivity, signal uniformity, and stability. We then used SERS for the early diagnosis of the fouling process and determining when the membrane pores would be blocked. The fouled area was visualized by a combination of the silver staining and Raman mapping. The fouling propensity of different proteins was studied by comparing the relative SERS band intensities of different proteins on a glass slide and after membrane filtration. Compared with fluorescence-based techniques, the narrow, well-resolved Raman band, especially the use of the same excitation line and laser power, endows SERS the ability to compare the fouling propensity in a very simple way.
膜污染是膜基技术的主要缺点，因为它会导致严重的通量下降，需要清洗或更换污染的膜。一种能够进行早期诊断、过程监测和评估不同污染物在污染过程中作用的技术，对于污染控制至关重要。我们开发了表面增强拉曼光谱（SERS）作为一种新的多功能工具，来研究蛋白质在聚偏氟乙烯（PVDF）膜上的污染过程以及三种不同蛋白质的污染倾向。我们优化了 SERS 活性 Ag 溶胶的聚集水平和体积以及光谱采集方法，并结合统计分析方法，以确保高检测灵敏度、信号均匀性和稳定性。然后，我们使用 SERS 进行污染过程的早期诊断，并确定何时会堵塞膜孔。通过银染和拉曼映射的结合，对污染区域进行可视化。通过比较不同蛋白质在玻璃载玻片上和膜过滤后的相对 SERS 带强度，研究了不同蛋白质的污染倾向。与基于荧光的技术相比，狭窄、分辨率良好的拉曼带，特别是使用相同的激发线和激光功率，使 SERS 能够以非常简单的方式比较污染倾向。
