Ionic Diffusion Coefficients of Cs^+, Pb^<2+>, Sm^<3+>, Ni^<2+>, SeO^<2->_4 and TcO^-_4 in Free Water Determined from Conductivity Measurements

概要

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The ionic diffusion coefficients for Cs+ Pb2+, Sm3+ Ni2+, SeO42- and TcO4- in free water (Do) were determined at room temperature by measuring conductivity. The Do values were derived based on the Nernst- Einstein equation. The limiting ionic equivalent conductivities (λo) for Cs+ Pb2+, Sm3+ Ni2+ and SeO42- were derived based on Kolrauschs square-root law and that for TcO4- was derived from the relation between the concentration of TcO4- in the solution and the λ because of its weak electrolyte. The Do values were in a range of 1.4 to 2.2×10-9m2/s. The Do values for Cs+ Pb2+, Sm3+ Ni2+ and SeO42- and those found in the literature showed good agreement. The Do for TcO4-, which was previously unknown, was determined to be 1.95×10-9m2/s, which is similar to that for analogous chemical species. The variation in Do has been expected to be approximately one order of magnitude at constant temperature and all Do values determined in this work were in this range. The variation in activation energy for diffusion for some important ions was less than a factor of two and it is concluded that the temperature dependence of Do is approximately the same.
社団法人日本原子力学会の論文
1996-12-25