离子交换树脂悬浊液的介电弛豫谱研究

研究了D354阴离子交换树脂分散在不同浓度KCl溶液中的悬浊液的频率域介电谱,发现在测量频率为106～107 Hz处出现了显著的介电弛豫现象,得出了介电常数、电导率以及弛豫时间随KCl溶液浓度的特异的变化关系,理论分析表明,该弛豫是一个以界面极化为主的非单一极化机制的弛豫过程,进而利用Maxwell-Wagner界面极化理论和双电层性质解释了该体系的特异介电行为,得到了树脂悬浊液在外加交变电场下的离子迁移和聚集信息,并确定了该树脂在静态平衡下双电层中对离子的相对离子强度.

Study on Dielectric Relaxation Spectroscopy of Ion- Exchange Beads Suspension

Dielectric measurement was carried out on D354 anion-exchange beads dispersed in KCl solutions with different concentrations. Distinct dielectric relaxations were observed in the frequency between 106 Hz and 107 Hz, and particular relations between permittivity, electric conductivity, relaxation time and the solution concentration were obtained. It was proved that such a relaxation is a non-single mechanism relaxation that due mainly to interfacial polarization, then the particular dielectric behavior was interpreted by the theory of Maxwell-Wagner and properties of electrical double layer, and the information of ion transformation and accumulation at the interface between the particles and solution phase in the presence of an external AC (alternative current) field was obtained. It is conclude that, the electric double layer that formed during the static ionic equilibrium would not be destroyed by added AC field; the enrichment of counterions in electric double layer predicts dielectric increment, while the thickness of electric double layer decides the magnitude of the relaxation frequency; and the ionic strength in electric double layer was fond corresponding to the ionic strength of pure KCl solution with a concentration of 0.7 mmol•L－1.