Lundberg, Daniel
- The Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences
Abstract
Phosphate (P-i) 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 P-31 and La-139 solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS), powder X-ray diffraction (PXRD) and sorption studies. P-31 SSNMR show that all P-i was immobilized as rhabdophane (LaPO(4.)n (HO)-O-2, n <= 3), which was further supported by La-139 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 mu M 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, P-31 SSNMR showed that rhabdophane formed upon P-i sequestration is in close proximity to the clay matrix.
Published in
Environmental Science and Technology
2015, volume: 49, number: 7, pages: 4559-4566
Publisher: AMER CHEMICAL SOC
SLU Authors
Global goals (SDG)
SDG6 Clean water and sanitation
UKÄ Subject classification
Oceanography, Hydrology, Water Resources
Materials Chemistry
Environmental Sciences
Publication identifier
- DOI: https://doi.org/10.1021/es506182s
Permanent link to this page (URI)
https://res.slu.se/id/publ/68375