Recently, cyclopentyl methyl ether (CPME) has found use as a commercially available solvent for various applications. As CPME shows better properties such as more hydrophobicity, less solublity in water, less volatility, and more stablity compared with typical ethereal solvents, it could be used as a diluent or an extractant in liquid-liquid extraction systems. In the present study, CPME was found to be useful for the extraction of Au(III) in hydrochloric acid media. Extraction of Au(III) increased with as increase in the hydrochloric acid concentration. Au(III) was selectively extracted using CPME from other precious metal ions and base metal ions. From the result of the dependency of the Au(III) concentration, CPME can load at least 0.93 g/dm 3 Au(III). Extracted Au(III) was quantitatively stripped from CPME using 0.1 M aqueous thiourea solution. As the solubility of water into CPME is much smaller than that into alcohols such as 1-hexanol, CPME is more favorable as an extractant for Au(III) in hydrochloric acid media.

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Complex impedance measurements were made on Gd-doped U02 to study Gd doping effects on electrical properties of the matrix and grain boundary. The Gd contents ranged from 0.5 to 10 wt%; temperature from 295 to 1.273 K; and frequency from 5 to 4 X 10 7 Hz.The matrix conductivity increased almost linearly with Gd content. indicating that the number density of electron holes also increased almost linearly with increasing Gd. The grain boundary capacitance of the Gd-doped uo. was larger than that of U02 by about 3 orders of magnitude. The grain boundary conductivity of the Gd-doped U02 was also larger than that of UO •. but decreased rapidly with increasing Gd content, between 0.5 to 10 wtq6. The migration energy of electron holes across a grain boundary was larger than that in the matrix and seemed to increase with Gd content.It was presumed from these results that Gd ions segregated to the grain boundaries to form a potential barrier for the migration of electron holes. The barrier thickness was estimated to be a few nanometers from the grain boundary capacitance. The energy barrier estimated from the migration energy of electron holes seemed to increase with Gd content.

To date, many kinds of chelating extractants have been developed, however, many of the good extractants are insoluble in aliphatic solvents. In the present study, cyclopentyl methyl ether (CPME) was assessed as a solvent for extractants to develop new solvent extraction systems. Many of the extractants (100 mM) were soluble in CPME. The extraction behavior of metal ions using a typical chelating extractant, 8-quinolinol (HQ) in CPME, was studied. The extraction profiles of metal ions using HQ in CPME were similar to those in toluene, whereas metal ions were extracted using HQ in 1-octanol and chloroform under lower pH conditions. The extraction reaction of In(III) using HQ in CPME was confirmed by slope analysis. A 3 : 1 complex between HQ and In(III) was formed in CPME by a proton exchange reaction, and the extraction equilibrium constant was determined. In(III), extracted using HQ in CPME, was quantitatively recovered using mineral acids. From the results, CPME was found to be a potential alternative solvent to other toxic organic solvents for the development of a solvent extraction system.