Zn Isotope Fractionation during Sorption onto Kaolinite

• DOI: 10.1021/acs.est.5b05347
• Publication Date: 2016-01-13T18:57:28Z
• Authors: Damien Guinoiseau; Alexandre Gélabert; Julien Moureau; Pascale Louvat; Marc F. Benedetti
• Keywords: Isotopes of zinc

In this study, we quantify zinc isotope fractionation during its sorption onto kaolinite, by performing experiments under various pH, ionic strength, and total Zn concentrations. A systematic enrichment in heavy isotopes on the surface of kaolinite was measured, with Δ66Znadsorbed-solution ranging from 0.11‰ at low pH strength to 0.49‰ high strength. Both measured concentration isotopic ratio are correctly described using a thermodynamic model that considers two binding sites: external basal surfaces edge sites. Based modeling approach, distinct factors were calculated: = 0.18 ± 0.06‰ for ion exchange sites, 0.49 specific complexation These indicate is dominantly controlled chemical composition solution (pH, strength).