本文模拟了难溶盐对纳滤膜的污染过程并对其进行了介电谱解析，探讨了介电谱作为一种监测膜内部或表面污染层信息的方法之可行性。测量了NF90、NF270、NF-三种商用纳滤膜分别被四种难溶盐（CaCO3、CaSO4、BaSO4、SrSO4）污染前后膜/液体系的介电谱，介电谱的差异是来自于因膜孔径的不同而分别由膜孔径的堵塞及同时由膜孔径的堵塞和膜表面形成结垢层共同导致的；解释了不同膜体系的介电弛豫机制：对于NF270、NF-体系，污染初期是由污染膜和水之间的界面极化和膜表面浓差极化共同决定；对于NF90体系而言，此时，不仅跟膜/水之间的界面极化和膜表面浓差极化有关，还与NF90膜表面形成的结垢层与水之间的界面极化有关；而4小时之后主要受界面极化所控制；分析了介电参数随污染时间的变化，发现膜孔径大小以及难溶盐的结晶机制均会对膜污染过程产生影响。进一步，利用引入了描述污染了的膜相及结垢相的常相位角元件（CPE）的等价回路模型，对介电谱进行了理论解析。研究表明，介电谱在监测纳滤膜难溶盐污染具有很有的潜力，另外，介电谱也可能为研究难溶盐浓差极化及难溶盐污染方面提供一些有用的信息。

The insoluble salt fouling process of nanofiltration membrane was simulated and the dielectric analysis were carried out. The feasibility of dielectric spectra as a noninvasive method to monitor the information on membrane fouling was discussed. The change of dielectric spectra of three industrial nanofiltration membranes NF90, NF270 and NF-, before and after fouled by CaCO3 , CaSO4, BaSO4, SrSO4, were observed, the difference between the dielectric spectra of these systems was due to the different fouling mode caused by the different membrane pore radius. The membrane NF270 and NF- were fouled in the inner of the membrane pore and NF90 was fouled on the membrane surface where a scaling layer formed. The dielectric relaxation mechanisms of different membrane systems were explained: The relaxation for the NF270、NF- membrane observed at the initial stage of fouling process was the result of cooperation of interfacial polarization (between the fouled membrane and deionized water) and the concentration polarization (near the membrane surface); for the NF90 membrne, the relaxation was not only due to the interfacial polarization (between the fouled membrane and deionized water) and the concentration polarization (near the membrane surface); For the NF90 membrane, but also to the interfacial polarization (between the scaling layer which formed on the membrane and deionized water);the relaxation after 4 hours was mainly controlled by the interfacial polarization between the fouled membrane and solution interface. Through the analysis of the dependence of dielectric parameters on the fouling time, it is indicated that both the value of membrane pore and the crystal mechanism of insoluble salts would influence the fouling process. Further, the dielectric spectra in theory by introducing a constant-phase-element(CPE) to circuit to describe the fouled membrane. Our finding infers that the dielectric spectra method is a powerful method to monitor the fouling process of internal and surface of the membrane non-invasively. In addition, the dielectric spectra could also supply some useful information to the concentration polarization and fouling process of insoluble salt research .