TY  - JOUR
A1  - Marang, Laura
A1  - Eidner, Sascha
A1  - Kumke, Michael Uwe
A1  - Benedetti, Marc F.
A1  - Reiller, Pascal E.
T1  - Spectroscopic characterization of the competitive binding of Eu(III), Ca(II) and Cu(II) to a sedimentary originated humic acid
N2  - The competition between REE, alkaline earth and d-transition metals for organic matter binding sites is still an open field of research; particularly, the mechanisms governing these phenomena need to be characterized in more detail. In this study, we examine spectroscopically the mechanisms of competitive binding of Eu(III)/Cu(II) and Eu(III)/ Ca(II) pair to Gorleben humic acid (HA), as previously proposed in the framework of the NICA-Donnan model. The evolution of time-resolved laser induced luminescence spectra of humic-complexed Eu(Ill) showed two strikingly different environments for a comparable bound proportion for Cu(II) and Ca(II). Cu(II) seems to compete more effectively with Eu(III) inducing its release into the Donnan phase, and into the bulk solution as free Eu3+. This is evidenced both by the shapes of the spectra and by the decrease in the luminescence decay times. In contrast with that, Ca(II) induces a modification of the HA structure, which enhances the luminescence of humic-bound Eu(III), and causes a minor modification of the chemical environment of the complexed rare earth ion.
Y1  - 2009
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/30771
UR  - http://www.sciencedirect.com/science/journal/00092541
SN  - 0009-2541
ER  -