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提出了电导率呈指数型分布的浓差极化层的介电模型.利用传递方程研究了压力驱动膜过程的介电谱,并导出层内电导率分布与宏观测量的电容和电导之间定量关系的理论表达式,得到介电谱高低频特征值与浓差极化模数之间的关系.计算结果表明,较之线性分布电导率,指数型分布电导率能更好地描述浓差极化层的介电谱.研究表明,介电谱及其特征值和弛豫强度随浓差极化模数和层厚度显著变化.对由分离膜、主体溶液和浓差极化层组成的复合体系的介电谱进行了数值模拟,发现电导较之电容其频率依存关系对浓差极化模数的变化更为敏感,上述研究为利用介电谱在线监测膜分离过程提供了有价值的理论参考。
The dielectric model of the concentration polarization layer with exponential distribution of conductivity is proposed.The dielectric spectrum of the pressure driven membrane is studied by using the transfer equation, and the conductivity distribution in the layer is derived from the quantitative measurement of capacitance and conductance Relationship between the theoretical expression of dielectric low and high frequency eigenvalues and concentration polarization modulus relationship between the results show that, compared to the linear distribution of conductivity, the exponential distribution of conductivity can better describe the concentration pole The dielectric spectra of the layers show that the dielectric spectra, their eigenvalues and the relaxation strengths vary significantly with the concentration polarization and the thickness of the layers. For the composite consisting of the separation membrane, the host solution and the concentration polarization layer The results show that the dependence of the conductance on the capacitance is more sensitive to the change of the concentration polarization modulus. These studies provide a valuable theory for on-line monitoring of the membrane separation process using dielectric spectroscopy reference.