Speciation and role of iron phases in cement to fix heavy metals J. - - PowerPoint PPT Presentation

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, France 2 : ARDEVIE, Europole Méditerranéen de l’Arbois, 13545 Aix en Provence, France 3: INERIS Domaine du Petit Arbois, BP 33, 13545 Aix en Provence, France 4: LERM, 10, rue Mercoeur, 75011 Paris, France

October 12-16, 2008 Le Croisic/France

rose@cerege.fr 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 MonosulfoAlCa Gel of Si and Al CSH décalc. CSH

Low Ca/Si

Ettringite++ Hydrog. Ca/Si Ettringite Portlandite CSH Ettringite MonosulfoAlCa

Water (Without carbonate)

Dissolution fronts Altered zone

hydrogarnet

hydrogarnet

Can fix heavy metals Can fix heavy metals

0.5 1 1.5 2 2.5 2000 4000 6000 8000 Ca norm S Normalized concentration distance from solid-water interface (µm)

Unaltered layer Unaltered 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)

0.5 1 1.5 2 2.5 2000 4000 6000 8000 Ca norm S Normalized concentration distance from solid-water interface (µm)

E t t r i n g i t e E t t r i n g i t e f r

• n

t f r

• n

t A l t e r e d A l t e r e d l a y e r l a y e r

0.5 1 1.5 2 2.5 2000 4000 6000 8000 Ca norm S Normalized concentration distance from solid-water interface (µm)

0.5 1 1.5 2 2.5 2000 4000 6000 8000 Ca norm S Normalized concentration 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 layer Unaltered layer Ettringite Ettringite front front A l t e r e d A l t e r e d l a y e r l a y e r Fe Fe

XGT-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

• xidation-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…) Adsorption Adsorption

Nutrients Nutrients Pollutants Pollutants

FeOOH amorphous FeOOH amorphous = ferrihydrite = ferrihydrite FeOOH / Fe FeOOH / Fe2

2O

O3

3 crystallised

crystallised (Goethite, hematite (Goethite, hematite… …) )

Iron (oxy-hydr-)oxides for waste treatment

Highly reactive minerals Many 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 surface surface

0.5 1 1.5 2 2.5 2000 4000 6000 8000 Ca norm S Fe Normalized concentration distance from solid-water interface (µm) 0.5 1 1.5 2 2.5 2000 4000 6000 8000 Ca norm S Fe Pb Normalized concentration 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

Anhydrous phase Cement hydration = dissolution + precipitation

calcium silicates C3S, C2S 3 CaO.SiO2 2 CaO.SiO2 Calcium Aluminates C3A 3 CaO.Al2O3

calcium-ferric aluminate

C4AF 2 CaO (Al2O3, Fe2O3)

CaSO4 CaSO4 Hydrated phases C-S-H xCaO.SiO2.yH2O C3(A,F)H6 3CaO.(Al2O3 ,Fe2O3).6H2O Ca(OH)2 AFm AFt (ettringite) “ferric” phase (‘hydrated phase: FeOOH)?)

M Mö öschner schner et al, et al, GCA, 2008 GCA, 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?? Ettringite

M Mö öschner schner et al et al GCA 2008: GCA 2008: Not starting from C4AF Not starting from C4AF

Teoreanu et al. (1979), Fukuhara et al. (1981), Rogers and Aldrige (1977), and Brown (1987) : amorphous FeOOH phase can exist No molecular scale investigation

Iron in other cements: slag,…

Fe C2F/C4AF FeO Fe3O4

Aim of the work

To determine the speciation of iron on synthetic

system (C4AF…)

To determine the speciation of iron on OPC… (still

• ngoing 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 phases iron speciation in cement phases

From cm From cm

1cm 1 mm

S Cr Mg

100 µm

mm mm µ µm m

O

Fe Fe As

2 R(Å) 4 6

Si Ca

Polarized light microscope Polarized light microscope XRD XRD… … SEM-EDX µ-XRF (fragile samples) (synchrotron (small spot size, sensitive)) XAS XAS Micro Micro-

• XAS

XAS (synchrotron) (synchrotron) Å Å

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 L22p1/2 H 13.6 (eV) …. Ar 3205.9 326.3 250.6 K 3608.4 378.6 297.3 Ca 4038.5 438.4 349.7 … Ti 4966 560.9 460.2 V 5465 626.7 519.8 Cr 5989 696 583.8 Mn 6539 769.1 649.9 Fe

7112

844.6 719.9

L 1,2,3 K M 1,2,3,4,5

6 68 80 00 7 70 00 00 7 72 20 00 7 74 40 00 7 76 60 00 7 78 80 00 8 80 00 00

1 s 1 s E E E E

C C

μ

White line

Atome central Central Atom

Prépic Pré-edge Edge= XANES EXAFS EXAFS

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 de Fourier inverse

EXAFS curve = Fingerprint of the atomic structure

XANES = fingerprint EXAFS = fingerprint

Reference spectra : Redox state Symmetry

7100 7120 7140 7160 7180 Energy (eV) FeOOH (ferrihydrite) γ-FeOOH (Lepidocrocite) C4AF C2AF Fe(II) CO3 Fe

3O 4 Magnetite

αFe

2O 3Hematite

From 0 to From 0 to … … 6 6-

• 10

10 Å Å (multiple scattering : high e mean free path) (multiple scattering : high e mean free path)

4 6 8 10 12

• 1
• 0.5

0.5 1 1.5 2

k*χ(k) k(Å-1)

C2F C4AF Lepidocrocite Ferrihydrite Fe rich clay (smectite) Nontronite (Fe-Si clay) Gœthite Akaganeite Hematite Magnetite Maghemite Siderite AFm Ettringite

XANES = fingerprint EXAFS = fingerprint

Reference spectra : Redox state Nature, number

And distance of neighboring atoms

From 0 to From 0 to … … 4 4-

• 5

5 Å Å (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

0.6

kχ(k) K(Å

• 1)

Ettringite C4AF Sample = 0.6 Ettringite + 0.4 C4AF

The same The same with XANES with 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-ray counts

C3AH6 C3AH6

Rose et al, Waste Management, 2006 Rose et al, Waste Management, 2006

Complete hydration : C3AH6 Complete 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 H C4AF hydrated 48 H C4AF anhydrous 2 theta (°) (Co kα) 8.2 Å 7.7 Å Anhydrous C4AF 7.5 Å C3AH6 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

0.5 1 1.5 2

k*χ(k) k(Å-1)

C2F C4AF Lepidocrocite Ferrihydrite Fe rich clay (smectite) Nontronite (Fe-Si clay) Gœthite Akaganeite Hematite Magnetite Maghemite Siderite AFm Ettringite

AFm AFm and and Ettringite Ettringite from from Moschner Moschner et al GCA, 2008 et al GCA, 2008

EXAFS results at the Fe K edge

4 6 8 10 12

• 0.4

0.4 0.8 1.2

k*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

0.4 0.8 1.2

k*χ(k) k(Å-1)

C4AF hydrated 24 h C4AF hydrated 48 h Calculated curve 59 % C4AF 15 % ferrihydrite 19 % Goethite C4AF anhydrous AFm Ettringite Goethite Ferrihydrite

4 6 8 10 12

• 0.4

0.4 0.8 1.2

k*χ(k) k(Å-1)

C4AF hydrated 24 h C4AF hydrated 48 h C4AF anhydrous

4 6 8 10 12

• 0.4

0.4 0.8 1.2

k*χ(k) k(Å-1)

C4AF hydrated 24 h C4AF hydrated 48 h

4 6 8 10 12

• 0.4

0.4 0.8 1.2

k*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, 2008 et al GCA, 2008

?? Difficulty ?? Difficulty to fit to fit ± ±10 10-

• 15%

15%

EXAFS results at the Fe K edge

EXAFS modelling χ(k) = − NiS0

2

kRi fi θ,k,R i

( )e −2σi

2k2 e

−2Ri λ(k) sin 2kR i + φi(k) + 2δ c(k)

( )

i=1 N

∑

amplitude amplitude phase phase R R Ca Ca O O R R Fe

Fe-

• O

O = 2

= 2 Å Å R R Fe

Fe -

• -
• Ca

Ca = 3.4

= 3.4 Å Å N N Fe

Fe-

• O

O = 6

= 6 N N Fe

Fe -

• -
• Ca

Ca = 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

1 2 3 4 6 8 10 12 14 experimental C4AF (48H) calculated k

3χ(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

Fe Fe-

• Ca

Ca 3.51 3.51Å Å 6 6

AFm

Fe Fe-

• Ca

Ca 3.35 3.35 Å Å 6 6 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 + + hydrogarnet hydrogarnet

What about Portland cement?? 24 H.. C4AF + FeOOH

4 6 8 10 12

• 0.4

0.4 0.8 1.2

k*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

0.4 0.8 1.2

k*χ(k) k(Å-1)

hydrated portland cement C4AF hydrated 48 h Calculated curve 30 % C4AF 12 % FeOOH 44 % AFm AFm Ettringite Goethite Ferrihydrite

4 6 8 10 12

• 0.4

0.4 0.8 1.2

k*χ(k) k(Å-1)

hydrated portland cement C4AF hydrated 48 h Calculated curve 30 % C4AF 12 % FeOOH 44 % Ettringite AFm Ettringite Goethite Ferrihydrite

Iron in hydrated Portland cement

AFm AFm Ettringite Ettringite?? ??

Iron in hydrated Portland cement

4 6 8 10 12

• 0.8
• 0.6
• 0.4
• 0.2

0.2 0.4

k*χ(k) k(Å-1)

hydrated portland cement Calculated curve 30 % C4AF 12 % FeOOH 44 % AFm surface of leached portland cement Calculated curve 32 % C4AF 36 % FeOOH 20 % AFm

In OPC at the micro scale

500 500µ µm m #1 #1 #2 #2 #3 #3 #4 #4

7100 7120 7140 7160 7180 7200 Energy (eV) #1 #2 #3 #4

7100 7120 7140 7160 7180 Energy (eV) FeOOH (ferrihydrite) γ-FeOOH (Lepidocrocite) C4AF C2AF Fe(II) CO3 Fe

3O 4 Magnetite

αFe

2O 3Hematite

µ µ-

• XRF (Fe)

XRF (Fe) Lucia (SLS) Lucia (SLS) ( (µ µ-

• XANES +

XANES + µ µ-

• 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

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) O Fe EXAFS at the Pb LIII edge (Pb+FeOOH)

• 0.6
• 0.4
• 0.2

0.2 0.4 0.6

4 6 8 10 12

Experimental Calculated k

3*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 mol.g-1 [Cr]e(mol.l-1)

eof the [Cr(III)+lime water] solution

EXAFS at the Cr K edge

Cr

Atomic pair R( ) σ( ) N Residue Cr--Cr/Fe 3.29 0.080 2.0 0.0375 Cr--Ca 3.48 0.080 3.6 Cr--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

1000 2000 3000 4000 5000 6000

X-ray counts 2 theta (°) (Co kα) 7.5 Å 8.2 Å 7.7 Å 9.6 Å Anhydrous C4AF 7.5 Å C3AH6

C4AF in presence of Cr(VI)

Al-Ca Layer Interlayer AFm Al Ca Interlayer site Al-Ca layer Al-Ca Layer Interlayer

• +

+ + + + +

Cr(VI)O4

2-

5980 6000 6020 6040 6060 6080 6100 C4AF + Cr(VI) Cr(VI) in solution (100%) Energy (eV)

And in leached Portland cement?

0.5 1 1.5 2 2.5 2000 4000 6000 8000 Pb Fe 0.5 1 1.5 2 2.5 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

Experimental Calculated

0.5 1 1.5 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
• 65

ppm Q2'' Q1 Q2 Q1'' Q1'

Rose et al, Rose et al, langmuir langmuir, 2002 , 2002

First EXAFS results (noisy)

4 6 8 10 12 k

2χ(k)

K(Å

• 1 )

Pb in hydrated Portlant cement Pb in leached Portlant cement 4 6 8 10 12

• 0.4
• 0.2

0.2 0.4 0.6 0.8

k

2χ(k)

K(Å

• 1 )

Pb in hydrated Portlant cement Pb in leached Portlant cement

First fits with First fits with Fe in the Fe in the second second coordination coordination sphere sphere Fe in second Fe in second coordination coordination sphere sphere

EXAFS results

1 2 3 4 5 6 FFT R+Δ(R) (Å) Pb in hydrated Portlant cement Pb in leached Portlant cement

More Iron More Iron No enough No enough… …

Conclusion

Existence of FeOOH amorphous phase after cement

hydration

Iron 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

Ca Ca S S Mg Mg 500 500µ µm m high high low low

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

1 2 3 4 5 6 Fonction de distribution radiale R(Å)

U-O U-OH U-Fe

1 2 3 4 5 6 Fonction de distribution radiale R(Å)

Pb-O Pb-Fe

1 2 3 4 5 6 Fonction de distribution radiale 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

2 4 6 8 10 12 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)

FeCl3 FeCl3 Fe(NO)3 Fe(NO)3 Edge Edge Double corner Double 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) = -33.4 SiOH + SiOH + SiO2(aq) + Ca2+ + Pb2+ - H2O – 4H+ <==> SiOH-CaSiOPb-SiOH log K(25°C) = -23.3

Experimental (µ-XRF) Calculated (CHESS-HYTEC) Benard Benard, Rose et al., , Rose et al., in prep in prep