speciation and role of iron phases in cement to fix heavy ...cement08.in2p3.fr/presentation workshop...
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2nd Mechanisms and modelling of waste/cement interactions international Workshop
Speciation and role of iron phases in cement to fix heavy metals
J. Rose1,2, A. Benard 2,3, A. Masion 1,2, P. Chaurand 1,2, I. Moulin 4, J-Y Bottero1,2
1: CEREGE UMR 6635 CNRS-Univ. Paul Cezanne, 13545 Aix en Provence, France2 : ARDEVIE, Europole Méditerranéen de l’Arbois, 13545 Aix en Provence, France
3: INERIS Domaine du Petit Arbois, BP 33, 13545 Aix en Provence, France4: LERM, 10, rue Mercoeur, 75011 Paris, France
October 12-16, 2008Le Croisic/France
[email protected] http://Se3d.cerege.fr
http://nano.cerege.fr
Fixation of heavy metals (HM) in cement (OPC)
Many OPC mineral phases can fix HM:
C-S-H : Pb, Zn, Eu…
AFm : Cr (III, VI),
Ettringite : almost all !!!
Other minor phases…. (LDH…)
Leaching of Portland cement (as an example)
Cement corrosion
Dissolution / precipitation pH modification
Altered zone
Non-Altered zone
Kamali, 2003
pH >12.5
pH<12.5
Adenot, 1992
CSH
MonosulfoAlCaGel
of S
i and
Al
CSH décalc.
CSH Low Ca/Si
Ettringite++
Hydrog.
Ca/SiEttringite
Portlandite
CSH
Ettringite
MonosulfoAlCa
Water(Without carbonate)
Dissolution fronts
Altered zone
hydrogarnet hydrogarnet
Can fix heavy metalsCan fix heavy metals
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Ca normS
Nor
mal
ized
con
cen
trat
ion
distance from solid-water interface (µm)
Unaltered layerUnaltered layer
XGT-5000 µ-XRF (HORIBA). (Rh X-ray
source, 15-50 KV voltage, 100-10 µm spot size
What about long term evolution (no ettringite…)
Leaching of Portland cement (as an example (30 days…at 35°C in water)
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Ca normS
Nor
mal
ized
con
cen
trat
ion
distance from solid-water interface (µm)
EttringiteEttringitefrontfront
Alte
red
Alte
red
lay e
rla
y er
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Ca normS
Nor
mal
ized
con
cen
trat
ion
distance from solid-water interface (µm)
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Ca normS
Nor
mal
ized
con
cen
trat
ion
distance from solid-water interface (µm)
Leaching of Portland cement (as an example)
What about long term evolution (no ettringite…)Iron ? Iron (III) is highly insoluble.
Unaltered layerUnaltered layerEttringiteEttringitefrontfront
Alte
red
Alte
red
lay e
rla
y er
FeFeXGT-5000 µ-XRF
(HORIBA). (Rh X-ray source, 15-50 KV voltage,
100-10 µm spot size
Iron (oxyhydr-)oxide in natural systems
Alteration (hydrolysis): very long term!!Formation of FeOOH/Fe2O3
Transport and fixation of numbers of species during
oxidation-precipitation
Fe(III)OOH
Fe(II)
Release of numbers of
species during reduction
Cycle dissolution-neoformation
Associated with redox front and biological
activity
Natural system: (in oxic zones, near neutral pH)
Adsorption and Adsorption and incorporation into the incorporation into the matrix (ferrihydrite) : matrix (ferrihydrite) : U, Cr, Co, Ni, Mn, As, Se, Pb, U…)
AdsorptionAdsorption
NutrientsNutrients PollutantsPollutants
FeOOH amorphousFeOOH amorphous= ferrihydrite= ferrihydrite FeOOH / FeFeOOH / Fe22OO33 crystallisedcrystallised
(Goethite, hematite(Goethite, hematite……))
Iron (oxy-hydr-)oxides for waste treatment
Highly reactive mineralsMany metals and metalloïds can be adsorbed or incorporated They are used as adsorbants (water treatment, physico-chemical processes)
Raw water
Coagulation-Floculation :
Coagulant: iron salt
sludge
Iron phases in cement?? µ-XRF profiles
Altered Altered surfacesurface
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Ca normSFe
Nor
mal
ized
con
cen
trat
ion
distance from solid-water interface (µm)
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Ca normSFePb
Nor
mal
ized
con
cen
trat
ion
distance from solid-water interface (µm)
After long term leaching : one of the only remaining phase?After long term leaching : one of the only remaining phase?
Iron in Portland cement
Anh
ydro
us p
hase
Cement hydration=
dissolution + precipitation
calcium silicates
C3S, C2S3 CaO.SiO22 CaO.SiO2
Calcium Aluminates
C3A3 CaO.Al2O3
calcium-ferric aluminate
C4AF2 CaO (Al2O3,Fe2O3)
CaSO4CaSO4
Hyd
rate
d ph
ases
C-S-HxCaO.SiO2.yH2O
C3(A,F)H6
3CaO.(Al2O3 ,Fe2O3).6H2O
Ca(OH)2AFm
AFt (ettringite)
“ferric” phase (‘hydrated phase: FeOOH)?)
MMööschner schner et al, et al, GCA, 2008GCA, 2008
Hydration of C4AF what do we know?
calcium ferroaluminates
C4AF?
AFm
+SO4 -SO4
C3AH6
Ettringite
calcium aluminates
C3AF
Al<=>Fe?AFm
C3AH6 + Fe phase??
EttringiteMMööschner schner et alet al
GCA 2008:GCA 2008:Not starting from C4AFNot starting from C4AF
Teoreanu et al. (1979), Fukuhara et al. (1981), Rogers and Aldrige (1977), and Brown (1987) :
amorphous FeOOH phase can existNo molecular scale investigation
Iron in other cements: slag,…
FeC2F/C4AFFeOFe3O4
Aim of the work
To determine the speciation of iron on synthetic system (C4AF…)
To determine the speciation of iron on OPC… (still ongoing research)
To determine the interaction with heavy metals on synthetic system
…. To determine the speciation on leached OPC…?
Molecular scale approach: determination of the Molecular scale approach: determination of the iron speciation in cement phasesiron speciation in cement phases
From cmFrom cm1cm
1 mm S
Cr
Mg
100 µm
mmmm µµmm
OFeFeAs
2 R(Å) 4 6
SiCa
Polarized light microscopePolarized light microscopeXRDXRD…… SEM-EDX
µ-XRF (fragile samples)
(synchrotron (small spot size,
sensitive))
XASXASMicroMicro--XASXAS
(synchrotron)(synchrotron)ÅÅ
Structure at the local scale : X-ray Absorption Spectroscopy
XANES = X-ray Absorption Near-Edge Spectroscopy : REDOX STATE
EXAFS = Extended X-ray Absorption Fine-Structure : ATOMIC ENVIRONMENT
Element K1S L1 2S L22p1/2H 13.6 (eV)….Ar 3205.9 326.3 250.6K 3608.4 378.6 297.3Ca 4038.5 438.4 349.7…Ti 4966 560.9 460.2V 5465 626.7 519.8Cr 5989 696 583.8Mn 6539 769.1 649.9Fe 7112 844.6 719.9
L 1,2,3K
M 1,2,3,4,566880000 77000000 77220000 77440000 77660000 77880000 88000000
1 s1 s
EE00
EECC
μWhite line
Atome centralCentral AtomPrépicPré-edge
Edge= XANES
EXAFSEXAFS
Backscatterer
Energie ( eV)
EXAFS
χ(k) =μ(k)− μ1(k)μ1(k) − μ0(k)
μ0(k)μ1(k)
a b
c d
e
χ(k) =μ(k) − μ1(k)μ1(k) − μ0 (k)
Transformée deFourier inverse
EXAFS curve = Fingerprint of
the atomic structure
XANES = fingerprintEXAFS = fingerprint
Reference spectra :
Redox state
Symmetry
7100 7120 7140 7160 7180Energy (eV)
FeOOH (ferrihydrite)
γ-FeOOH (Lepidocrocite)
C4AF
C2AF
Fe(II) CO3
Fe3O
4 Magnetite
αFe2O
3Hematite
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From 0 to From 0 to …… 66--10 10 ÅÅ(multiple scattering : high e mean free path)(multiple scattering : high e mean free path)
4 6 8 10 12
-1
-0.5
0
0.5
1
1.5
2
k*χ(
k)
k(Å-1)
C2F
C4AF
LepidocrociteFerrihydrite
Fe rich clay (smectite)
Nontronite (Fe-Si clay)
GœthiteAkaganeite
Hematite
Magnetite
Maghemite
Siderite
AFm
Ettringite
XANES = fingerprintEXAFS = fingerprint
Reference spectra :
Redox state
Nature, number And distance of neighboring atoms
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From 0 to From 0 to …… 44--5 5 ÅÅ(single scattering :(single scattering :low mean free path)low mean free path)
EXAFS
In a sample : Fe is in C4AF (40%) and Ettringite (60%)
4 6 8 10 12
kχ(k
)
K(Å -1 )
Ettringite
C4AF
Sample = 0.5 Ettringite + 0.5 C4AF
4 6 8 10 12-1.2
-0.6
0
0.6
kχ(k
)
K(Å -1 )
Ettringite
C4AF
Sample = 0.6 Ettringite + 0.4 C4AF
The same The same with XANESwith XANES
Local scale study
Procedure : – PCA, then linear combination… (XANES and EXAFS)– EXAFS modelling (XANES : still difficult on heterogeneous
sample)
With XAS : the fit does not indicate that the mineral exist: it reflects a similar atomic structure
XAS does not require long range order.
RESULTS : Hydration of C4AF in LW (without sulfate)
Hydration liquid/solid ratio of 0.5, 10, 60.
10 15 20 25 30 35 40 45 50
C4AF hydrated 48 H
C4AF Anhydrous
2 theta (°) (Co kα)
X-r
ay c
ount
s C3AH6C3AH6
Rose et al, Waste Management, 2006Rose et al, Waste Management, 2006
Complete hydration : C3AH6Complete hydration : C3AH6
Hydration of C4AF in LW (without sulfate)
Hydration liquid/solid ratio of 10
8 10 12 14 16 18 20 22
C4AF hydrated 24 HC4AF hydrated 48 HC4AF anhydrous
2 theta (°) (Co kα)
8.2 Å
7.7 Å Anhydrous C4AF7.5 ÅC3AH6
Where is Fe??Where is Fe??AFM =
transition phase
EXAFS results at the Fe K edge
Comparison with FeOOH, Fe-oxides; carbonates, AFm, Ettringite, C4AF, C2F
4 6 8 10 12
-1
-0.5
0
0.5
1
1.5
2
k*χ(
k)
k(Å-1)
C2F
C4AF
LepidocrociteFerrihydrite
Fe rich clay (smectite)
Nontronite (Fe-Si clay)
GœthiteAkaganeite
Hematite
Magnetite
Maghemite
Siderite
AFm
Ettringite
AFm AFm and and Ettringite Ettringite from from Moschner Moschner et al GCA, 2008et al GCA, 2008
EXAFS results at the Fe K edge
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
C4AF hydrated 24 h
C4AF hydrated 48 h
C4AF anhydrous
AFm
Ettringite
Goethite
Ferrihydrite
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
C4AF hydrated 24 h
C4AF hydrated 48 h
Calculated curve
59 % C4AF15 % ferrihydrite19 % Goethite
C4AF anhydrous
AFm
Ettringite
Goethite
Ferrihydrite
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
C4AF hydrated 24 h
C4AF hydrated 48 h
C4AF anhydrous
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
C4AF hydrated 24 h
C4AF hydrated 48 h
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
C4AF hydrated 24 h
C4AF hydrated 48 h
C4AF anhydrous
AFm
Ettringite
AFm AFm and and Ettringite Ettringite from from Moschner Moschner et al GCA, 2008et al GCA, 2008
?? Difficulty ?? Difficulty to fitto fit
±±1010--15%15%
EXAFS results at the Fe K edge
EXAFS modelling
χ(k) = −NiS0
2
kRifi θ, k,R i( )e −2σi
2k2e−2Ri
λ(k) sin 2kR i + φ i (k) + 2δ c(k)( )i=1
N
∑
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amplitudeamplitude phasephase
RR
CaCa
OOR R FeFe--OO = 2 = 2 ÅÅR R Fe Fe -- --CaCa = 3.4 = 3.4 ÅÅN N FeFe--OO = 6= 6
N N Fe Fe -- --CaCa = 8= 8
EXAFS results at the Fe K edge
EXAFS modelling
Fe Fe -- Fe distance : how can we go further?Fe distance : how can we go further?
-3
-2
-1
0
1
2
3
4 6 8 10 12 14
experimental C4AF (48H)
calculated
k3χ(
k)
k(Å -1 )
48 H
Structural approach
Fe-Fe =2.95-3.35Å
Fe-Fe > 3.70Å
Fe-Fe =2.87-2.90Å Fe-Fe =
3.45-3.60Å
Structural approach
Atomic pair Distance (Å) Number of Fe neighbours
Fe--Fe 3.01 2
Fe--Fe 3.28 2
Goethite(α-FeOOH)
Ferrihydrite(amorphous-
FeOOH)
Hemathite(α-Fe2O3)
C3AH6 FeFe--CaCa 3.513.51ÅÅ 66
AFm FeFe--CaCa 3.35 3.35 ÅÅ 66
Fe--Fe 3.46 4
Fe--Fe 3.01 4.5
Fe--Fe 3.43 3.9
Fe--Fe 2.90 1
Fe--Fe 2.97 3
Fe--Fe 3.36 3
Fe--Fe 3.70 6
48 H
Hydration of C4AF (in LW)
FeOOH FeOOH + + hydrogarnethydrogarnet
What about Portland cement??
24 H..C4AF + FeOOH
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
hydrated portland cement
C4AF hydrated 48 h
AFm
Ettringite
Goethite
Ferrihydrite
Iron in hydrated Portland cement
4 6 8 10 12
-0.4
0
0.4
0.8
1.2k*χ(
k)
k(Å-1)
hydrated portland cement
C4AF hydrated 48 h
Calculated curve
30 % C4AF12 % FeOOH44 % AFm
AFm
Ettringite
Goethite
Ferrihydrite
4 6 8 10 12
-0.4
0
0.4
0.8
1.2
k*χ(
k)
k(Å-1)
hydrated portland cement
C4AF hydrated 48 h
Calculated curve
30 % C4AF12 % FeOOH44 % Ettringite
AFm
Ettringite
Goethite
Ferrihydrite
Iron in hydrated Portland cement
AFmAFmEttringiteEttringite????
Iron in hydrated Portland cement
4 6 8 10 12-0.8
-0.6
-0.4
-0.2
0
0.2
0.4k*χ(
k)
k(Å-1)
hydrated portland cement
Calculated curve
30 % C4AF12 % FeOOH44 % AFm
surface of leached portland cement
Calculated curve
32 % C4AF36 % FeOOH20 % AFm
In OPC at the micro scale
500500µµmm
#1#1#2#2#3#3
#4#4
7100 7120 7140 7160 7180 7200Energy (eV)
#1
#2#3#4
7100 7120 7140 7160 7180Energy (eV)
FeOOH (ferrihydrite)
γ-FeOOH (Lepidocrocite)
C4AF
C2AF
Fe(II) CO3
Fe3O
4 Magnetite
αFe2O
3Hematite
µµ--XRF (Fe)XRF (Fe)Lucia (SLS)Lucia (SLS)((µµ--XANES + XANES + µµ--EXAFS)EXAFS)
Summary
Hydration of C4AF (-SO4) : FeOO + Fe in hydrogarnet (No Fe and AFm??)In presence of SO4 (CaSO4) : ettringite (Mochner et al, 2008)
In OPC : remaining C4AF (local scale) + FeOOH + AFm (??). More amorphous Fe at the surface.
What is the role of iron phases in heavy metal fixation
Stage 1: C4AF + Heavy metal interactions…
Stage 2 : on ‘real’ system…
C4AF hydrated in presence of metals
Fe and lead : isotherms: (L/S ratio (0.5 to 60); with LW, [Pb]initial from 10-3 to 8.10-3 mol/l)
“Everything”fixed by the solid
“Nothing” in solution
Reactivity between iron phases and metals (pure system)
Fe and lead : isotherms: (L/S ratio (0.5 to 60); with LW, [Pb]initial from 10-3 to 8.10-3 mol/l)
“Everything”fixed by the solid
“Nothing” in solution
C4AF hydrated in presence of metals
0 1 2 3 4 5 6 7 8
FDR
R(Å)
EXAFS at the Pb L edge
H2O
3.3 �
3.9 �
≈3.9 �
Pb radial distribution function
R(Å)
OFe
EXAFS at the Pb LIII edge
(Pb+FeOOH)
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
4 6 8 10 12
Experimental
Calculated
k3*χ
(k)
K(Å-1 )
((Bargar Bargar et al, 1998)et al, 1998)
C4AF hydrated in presence of metals
Fe in presence of Cr
10-6
10-5
10-4
10-7 10-6 10-5
C4AF hydrated with Cr(VI)
C4AF hydrated with Cr(III)
[Cr]
s m
ol.g
-1
[Cr]e(mol.l-1)
eof t
he
[Cr(
III)
+li
me
wat
er]
solu
tion
EXAFS at the Cr K edge
Cr
Atomic pair R(�) σ(�) N ResidueCr--Cr/Fe 3.29 0.080 2.0 0.0375
Cr--Ca 3.48 0.080 3.6Cr--Cr/Fe 3.55 0.102 3.5
C3A(Cr)H6 (Cr)FeOH
C4AF in presence of Cr(VI)
8 10 12 14 16 18 20 22
C4AF hydrated 24 H
C4AF hydrated 48 H
Anhydrous C4AF
C4AF + Cr(VI) fe/Cr=0.15
0
1000
2000
3000
4000
5000
6000
X-r
ay c
ount
s
2 theta (°) (Co kα)
7.5 Å
8.2 Å
7.7 Å
9.6 Å
Anhydrous C4AF7.5 Å
C3AH6
C4AF in presence of Cr(VI)
Al-Ca Layer
Interlayer
AFm
AlCa Interlayer site
Al-Ca layer
Al-Ca Layer
Interlayer
-+++
+ ++
Cr(VI)O42-
5980 6000 6020 6040 6060 6080 6100
C4AF + Cr(VI)
Cr(VI) in solution (100%)
Energy (eV)
And in leached Portland cement?
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Pb
Fe
0
0.5
1
1.5
2
2.5
0 2000 4000 6000 8000
Pb
Fe
Si
A
B
????????
Lead and C-S-H
~1 Si at 3,75Å de Pb~0,8 Ca at 3,58Å de Pb
Si
Ca
Pb
New peak at +85.6 ppm
Si
ExperimentalCalculated
0
0.5
1
1.5
0 1 2 3 4 5 6 7 8
FDR
R(Å)
EXAFS at the Pb LIII edge
CSH structure
CSH hydrated in presence of Pb
29Si NMR
-95-90-85-80-75-70-65ppm
Q2''
Q1 Q2
Q1''Q1'
Rose et al, Rose et al, langmuirlangmuir, 2002, 2002
First EXAFS results (noisy)
4 6 8 10 12
k2χ(
k)
K(Å -1 )
Pb in hydrated Portlant cement
Pb in leached Portlant cement
4 6 8 10 12-0.4
-0.2
0
0.2
0.4
0.6
0.8
k2χ(
k)
K(Å -1 )
Pb in hydrated Portlant cement
Pb in leached Portlant cementFirst fits with First fits with Fe in the Fe in the second second coordination coordination sphere sphere
Fe in secondFe in secondcoordinationcoordinationspheresphere
EXAFS results
0 1 2 3 4 5 6
FFT
R+Δ(R) (Å)
Pb in hydrated Portlant cement
Pb in leached Portlant cement
More IronMore Iron No enoughNo enough……
Conclusion
Existence of FeOOH amorphous phase after cement hydrationIron phases formed after C4AF hydration strongly “incorporate” metals (Cr, Pb…)Metal and iron in cement: needs further investigation (µ-XRF at the micron scale in leached zones…)Implications: iron(III) phases may play a positive role for the long term fixation of metals and metalloids…but under oxic conditions (reductive dissolution of iron).
Acknowledgment
J-L Hazemann and O. Proux (ESRF, FAME beamline)V. Briois (LURE, D44 beamline and SOLEIL Samba)A-M Flank (SLS-Soleil, Lucia beamline)
Funding from the European Community through the INERWASTE Craft European program, and the YPREMA company.
4 00 µm
CaCa
SS
MgMg
500500µµmm
highhigh
lowlow
µ-XRF
XGT-5000 X-ray spectro-microscope (HORIBA). (Rh X-ray source, 15 KV voltage, 10 µm spot
Reactivity of Iron oxide
Highly reactive particles(U, Cr, Co, Ni, Mn, As,
Se, Pb, U…)
Selenate
lead
Uranium
0 1 2 3 4 5 6
Fonc
tion
de d
istri
butio
n ra
dial
e
R(Å)
U-O
U-OHU-Fe
0 1 2 3 4 5 6
Fonc
tion
de d
istri
butio
n ra
dial
e
R(Å)
Pb-O
Pb-Fe
0 1 2 3 4 5 6
Fonc
tion
de d
istri
butio
n ra
dial
e
R(Å)
Se-O
Se-Fe
Reactivity of iron oxide
Structural approach
AFm
Atomic pair Distance Number
Al/Fe-O 1.91Å 6
Fe--Ca 3.51Å 6
Al/Fe-O 1.90Å 6
Al/Fe--Ca 3.35Å 6
C3AH6
EXAFS
0
2
4
6
8
10
12
0 1 2 3 4 5 6 7 8
F(R
)
R (A)
Transformée de Fourier: Probabilité de présence des atomes voisins de l’élément X.
Central atom
1st coordination sphere
2nd coordination sphere
Nucleation and growth of FeOOH (in water) = Ferrihydrite??
(Bottero et al, 1994, Rose et al, 1997)
Fe24 (16Å)
FeCl3FeCl3
Fe(NO)3Fe(NO)3
EdgeEdge
Double cornerDouble corner
Modeling
Calculation:Translation into a chemical-transport model code (CHESS-HYTEC)
Translation of experimental data into thermodynamic data
For Pb retention sites (Nonat C-S-H model (Nonat et al, 01, Pointeau ,01)SiOH + Ca2+ + Pb2+ + 3H2O – 4H+ <==> SiOCaPb(OH)3 log K(25°C) = -33.4SiOH + SiOH + SiO2(aq) + Ca2+ + Pb2+ - H2O – 4H+ <==> SiOH-CaSiOPb-SiOH log K(25°C) = -23.3
Experimental(µ-XRF) Calculated
(CHESS-HYTEC)
BenardBenard, Rose et al., , Rose et al., in prepin prep