Probing the surface structure of divalent transition metals using surface specific solid-state NMR spectroscopy.
Environmental and geochemical systems containing paramagnetic species could benefit by using nuclear magnetic resonance (NMR) spectroscopy due to the sensitivity of the spectral response to small amounts paramagnetic interactions. In this study, we apply commonly used solid-state NMR spectroscopic methods combined with chemometrics analysis to probe sorption behavior of the paramagnetic cations Cu(2+) and Ni(2+)at the amorphous silica surface. We exploit the unique properties of paramagnets to derive meaningful structural information in these systems at low, environmentally relevant cation surface loadings by comparing the NMR response of sorption samples to paramagnetic free samples. These data suggest that a simple sorption model where the cation sorbs as inner sphere complexes at negatively charged, deprotonated silanol sites is appropriate. These results help constrain sorption models that are used to describe metal fate and transport.
Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue Livermore, California 94551, United States.
Harris E
HE
Mason
Stephen J
SJ
Harley
Robert S
RS
Maxwell
Susan A
SA
Carroll
D000327:Adsorption; D002413:Cations, Divalent / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D012996:Solutions; D013499:Surface Properties; D013997:Time Factors; D028561:Transition Elements / Q000737:chemistry*
D002413:Cations, Divalent; D008024:Ligands; D008670:Metals; D012996:Solutions; D028561:Transition Elements