Environmental Science & Technology · 2015 · 140 citations · 61 references
Natural SciencesChemistryEarth SciencesInorganic ChemistryMineralogySoil ChemistryClay MineralogyClay MineralsMineral ChemistryMineral-organic InteractionsNutrient MineralizationPhosphate MineralsBinding CapacityClay Mineral ChemistryClay Mineral ImmobilizationClay-organic Matter InteractionsDissolved Organic Carbon SorptionLake RestorationNutrient AdsorptionSorption
Phosphate (Pi) sequestration by a lanthanum (La) exchanged clay mineral (La-Bentonite), which is extensively used in chemical lake restoration, was investigated on the molecular level using a combination of (31)P and (139)La solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS), powder X-ray diffraction (PXRD) and sorption studies. (31)P SSNMR show that all Pi was immobilized as rhabdophane (LaPO4·n H2O, n ≤ 3), which was further supported by (139)La SSNMR and EXAFS. However, PXRD results were ambiguous with respect to rhabdophane and monazite (LaPO4). Adsorption studies showed that at dissolved organic carbon (DOC) concentration above ca. 250 μM the binding capacity was only 50% of the theoretical value or even less. No other La or Pi phases were detected by SSNMR and EXAFS indicating the effect of DOC is kinetic. Moreover, (31)P SSNMR showed that rhabdophane formed upon Pi sequestration is in close proximity to the clay matrix.
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E.I. Hamilton · Marine Pollution Bulletin · 1984 · 3.7K citations
Multiple-scattering calculations of x-ray-absorption spectra
S. I. Zabinsky, J. J. Rehr, A. L. Ankudinov et al. · Physical review. B, Condensed matter · 1995 · 2.9K citations