ELECTROCHEMICAL CHARACTERIZATION OF COMPOSITE MEMBRANES BASED ON CROWN-ETHERS INTERCALATED INTO MONTMORILLONITE

被引:23
作者
ARANDA, P
GALVAN, JC
CASAL, B
RUIZHITZKY, E
机构
[1] CSIC,INST CIENCIA MAT MADRID,C SERRANO 115 BIS,E-28006 MADRID,SPAIN
[2] CSIC,CTR NATL INVEST MET,MADRID 6,SPAIN
关键词
MEMBRANES; IMPEDANCE; CROWN-ETHERS; MONTMORILLONITE; ION-CONDUCTIVITY;
D O I
10.1007/BF00659285
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Oxyethylene macrocyclic compounds (crown-ethers) act as ligands of intracrystalline cations of certain layered silicates as montmorillonites. Stable intercalation materials are formed which are used to prepare organic-inorganic membranes by encapsulating these intercalation compounds with a polybutadiene thin coating. Electrochemical Impedance Spectroscopy (EIS) is used to study the resulting composite membranes in contact with aqueous electrolytes. From the impedance plots, the ionic resistance of the membranes is obtained. The thickness of the polybutadiene coating is an important factor determining the ability of ions to pass across the membrane. Marked differences in the ionic resistance are observed as a function of the nature of the interlayer macrocyclic compound. For non-intercalated montmorillonite membranes, the ionic resistance is strongly reduced, whereas for some crown-ether intercalated materials such as 18-crown-6 and dibenzo 24-crown-8, iono-selective membranes are obtained. Concerning the nature of the electrolyte, cations exhibiting greater hydration energies show higher difficulties to pass through the membrane and, consequently, the ionic resistance increases.
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页码:712 / 720
页数:9
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