- TAYLOR & FRANCIS LTD
Humic substances (HSs) are ubiquitous in various environments including deep underground and play an important role in the speciation and mobility of radionuclides. The binding of Eu3+, a chemical homologue of trivalent actinide ions, to HSs isolated from sedimentary groundwater at -250m below the surface was studied by time-resolved laser fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) as a function of pH and salt concentration. PARAFAC modeling reveals the presence of multiple factors that correspond to different Eu3+ species. These factors resemble those observed for Eu3+ binding to HSs from surface environments; however, detailed comparison shows that there are some particularities in Eu3+ binding to the deep groundwater HSs. The distribution coefficients (K-d) of Eu3+ binding to the HSs calculated from the PARAFAC modeling exhibits a rather strong salt effect. At 0.01M NaClO4, the K-d values are relatively large and comparable to those to the surface HSs; they are decreaed at 0.1M NaClO4 by more than an order of the magnitude. The K-d values are larger for the humic acid fraction of the deep underground HSs than the fulvic acid fraction over the entire range of pH and salt concentration investigated in this study.
Web of Science ® 被引用回数 : 2
Web of Science ® の 関連論文(Related Records®)ビュー