Analytical Sciences

Abstract − Analytical Sciences, 35(10), 1129 (2019).

Extraction Mechanism of Lanthanide Ions into Silica-based Microparticles Studied by Single Microparticle Manipulation and Microspectroscopy
Toshiki OTAKA,* Tatsumi SATO,* Simpei ONO,** Kohei NAGOSHI,** Ryoji ABE,** Tsuyoshi ARAI,** Sou WATANABE,*** Yuichi SANO,*** Masayuki TAKEUCHI,*** and Kiyoharu NAKATANI*
*Division of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
**Shibaura Institute of Technology, Toyosu, Tokyo 135-8548, Japan
***Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1194, Japan
Single porous silica microparticles coated with a styrene-divinylbenzene polymer (SDB) impregnated with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) were injected into an aqueous 3 mol/L nitric acid solution containing trivalent lanthanide (Ln(III)), as a high-level liquid waste model. We used the microcapillary manipulation-injection technique; and the extraction rate of Ln(III), as an Ln(III)-CMPO complex, into the single microparticles was measured by luminescence microspectroscopy. The extraction rate significantly depended on the Ln(III), CMPO, or NO3 concentration, and was analyzed in terms of diffusion in the pores of the microparticles and the complex formation of Ln(III). The results indicated that the rate-determining step in Ln(III) extraction was diffusion in the pore solution of the microparticles.