Characterization of phosphate sequestration by a lanthanum modified bentonite clay: A solid-state NMR, EXAFS and PXRD study

Line Dithmer, Andrew S Lipton, Kasper Reitzel, Terence Edwin Warner, Daniel Lundberg, Ulla Gro Nielsen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

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 31P and 139La solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS) and powder X-ray diffraction (PXRD) and sorption studies. 31P SSNMR show that all phosphate was immobilized as rhabdophane (LaPO4·n H2O, n  3), which was further supported by 139La 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 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, 31P SSNMR showed that rhabdophane formed upon Pi sequestration is in close proximity to the clay matrix.
OriginalsprogEngelsk
TidsskriftEnvironmental Science & Technology (Washington)
Vol/bind49
Udgave nummer7
Sider (fra-til)4559-4566
Antal sider9
ISSN1086-931X
DOI
StatusUdgivet - mar. 2015

Fingeraftryk

Bentonite
Lanthanum
bentonite
X ray powder diffraction
Nuclear magnetic resonance spectroscopy
nuclear magnetic resonance
Phosphates
spectroscopy
X-ray diffraction
Nuclear magnetic resonance
phosphate
clay
Organic carbon
dissolved organic carbon
X ray absorption spectroscopy
monazite
atomic absorption spectroscopy
Clay minerals
X-ray spectroscopy
Restoration

Citer dette

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title = "Characterization of phosphate sequestration by a lanthanum modified bentonite clay: A solid-state NMR, EXAFS and PXRD study",
abstract = "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 31P and 139La solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS) and powder X-ray diffraction (PXRD) and sorption studies. 31P SSNMR show that all phosphate was immobilized as rhabdophane (LaPO4·n H2O, n  3), which was further supported by 139La 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 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, 31P SSNMR showed that rhabdophane formed upon Pi sequestration is in close proximity to the clay matrix.",
author = "Line Dithmer and Lipton, {Andrew S} and Kasper Reitzel and Warner, {Terence Edwin} and Daniel Lundberg and Nielsen, {Ulla Gro}",
year = "2015",
month = "3",
doi = "10.1021/es506182s",
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pages = "4559--4566",
journal = "Environmental Science & Technology (Washington)",
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Characterization of phosphate sequestration by a lanthanum modified bentonite clay: A solid-state NMR, EXAFS and PXRD study. / Dithmer, Line; Lipton, Andrew S; Reitzel, Kasper; Warner, Terence Edwin; Lundberg, Daniel; Nielsen, Ulla Gro.

I: Environmental Science & Technology (Washington), Bind 49, Nr. 7, 03.2015, s. 4559-4566.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Characterization of phosphate sequestration by a lanthanum modified bentonite clay: A solid-state NMR, EXAFS and PXRD study

AU - Dithmer, Line

AU - Lipton, Andrew S

AU - Reitzel, Kasper

AU - Warner, Terence Edwin

AU - Lundberg, Daniel

AU - Nielsen, Ulla Gro

PY - 2015/3

Y1 - 2015/3

N2 - 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 31P and 139La solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS) and powder X-ray diffraction (PXRD) and sorption studies. 31P SSNMR show that all phosphate was immobilized as rhabdophane (LaPO4·n H2O, n  3), which was further supported by 139La 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 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, 31P SSNMR showed that rhabdophane formed upon Pi sequestration is in close proximity to the clay matrix.

AB - 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 31P and 139La solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS) and powder X-ray diffraction (PXRD) and sorption studies. 31P SSNMR show that all phosphate was immobilized as rhabdophane (LaPO4·n H2O, n  3), which was further supported by 139La 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 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, 31P SSNMR showed that rhabdophane formed upon Pi sequestration is in close proximity to the clay matrix.

U2 - 10.1021/es506182s

DO - 10.1021/es506182s

M3 - Journal article

VL - 49

SP - 4559

EP - 4566

JO - Environmental Science & Technology (Washington)

JF - Environmental Science & Technology (Washington)

SN - 0013-936X

IS - 7

ER -