Transport of colloids and nanoparticles in saturated porous media

Part of an Excellence Ph.D. Course
Politecnico di Torino – June 27th, 2012
DITAG
A talk on:
Transport of colloids and nanoparticles in saturated
porous media for environmental remediation
Rajandrea SETHI, Tiziana TOSCO and GROUNDWATER
ENGINEERING GROUP
DIATI – Politecnico di Torino
1
ZVI
Permeable reactive barrier
2
1
Degrades
Transformation and
immobilization of inorganic
contaminants
Degradation of organic
contaminants
3
TCE degradation pathways
4
2
Use of ZVI to remediate contaminated
aquifers
Nanoscale iron
Freyria et al. 2007
Millimetric iron
0.25 – 2 mm
15 – 100 nm
5
ZVI vs MZVI & NZVI
MZVI & NZVI
Source & plume treatment
ZVI
Plume treatment
0.25 – 2 mm
Installation:
High costs
Difficult, depth <30m
Standard practice
15 nm → 100 µm
Installation:
Low costs
Injected, depth < 70m
Under development
6
3
High specific surface area
1 kg of nanoscale iron
= 2 x Stadio Olimpico (Roma)
FESEM (Tecnogranda)
∼30000 m2
7
Degradation kinetics
Fe0 + RCl + H+ → RH + Fe2+ + Cl
Degradation kinetics:
dcTCE
= −kcTCE = −(k M ⋅ c Fe ) ⋅ cTCE = −(k SA ⋅ SSA ⋅ c Fe ) ⋅ cTCE
dt
dove k pseudocinetica del I ordine [T ], k cinetica all’unità di SA e c [LT ], k
cinetica all’unità di c [L M T ], SSA superficie specifica [L M ], c
concentrazione di ferro per volume di acqua [ML ], c
concentrazione del
contaminante.
-1
Fe
3
-1
-1
SA
Fe
2
-3
-1
-1
M
Fe
TCE
8
4
MZVI & NZVI: suspension
stability
MZVI
NZVI
(1-100 µm)
relevant mass,
high density
gravitational sedimentation
(15–100 nm)
particle – particle
attraction
aggregation (single domain)
9
NZVI: aggregation
The application is hindered by aggregation
10
5
MZVI & NZVI: suspension
stability
MZVI
NZVI
(1-100 µm)
(15–100 nm)
relevant mass,
high density
sedimentation
particle – particle
attraction
&
aggregation
Reactivity:
□ Lower, due to reduced surface area
Injection:
□ Sedimentation during pumping and inside the wells
□ Reduced radius of influence
Transport:
11
□ Filtered/strained in the porous medium, reduced contact with contaminants
NZVI: Thermodynamic
stabilization
Modification of surface properties: low concentrations of
polymers adsorbed on particles surface providing:
Electrostatic stabilization:
repulsive forces due to the surface
charge of the polymer layer
□ short-ranged
□ affected by ionic strength
Steric stabilization:
repulsion due to osmotic
and elastic forces
□ long-ranged if MW is high
□ indifferent to ionic strength
IS
With polimer
No polimer
12
6
MZVI & NZVI: stabilization
Stabilization: via addition of green
polymers (guar gum and xanthan gum)
1.
GREEN: natural origins from the seed of the guar
plant
2.
INEXPENSIVE: Sigma-Aldrich:
Commercial:
3.
COMMERCIALLY AVAILABLE: food industry
44.60
~2
€/kg
€/kg
13
NZVI: Thermodynamic
stabilization
DLS measurements (guar gum 0.5 g/l):
600
Bare particles
MRNIP
Guar gum-coated particles
10mM NaCl
500
500
Radius (nm)
Hydrodynamic Radius (nm)
400
300
200
400
Initial Particle Size
300
200
Initial Particle Size
100
0
0
1000 2000 3000 4000
Time (s)
154 mg/l
231 mg/l
Particle Concentration (mg/L)
Decrease of the hydrodynamic radius
Bare Particles
Particles in solution of Guar Gum 0.5 g/L
Reduced aggregation
Tiraferri, A.; Chen, K.L.; Sethi, R.; Elimelech, M. Reduced aggregation and sedimentation of zero-valent iron nanoparticles in the
presence of guar gum. Journal of Colloid and Interface Science 2008, 324(1-2), 71-79.
14
7
MZVI: Kinetic stabilization
Modification of fluid properties: reduced frequency of
particle collisions.
Shear-thinning solution of xanthan, guar gum (3-10 g/l)
G
ua
rg
High viscosity at
low shear rate
↓
Reduced
sedimentation
& aggregation
um
so
l
ut
io
n
Low viscosity at
low shear rate
↓
Easily injected
water
Comba, S.; Dalmazzo, D.; Santagata, E.; Sethi, R. Rheological characterization of NZVI suspensions for injection in porous media.
Journal of Hazardous Materials (submitted) 2010.
15
MZVI: Kinetic stabilization
Sedimentation curves for MZVI in guar gum (5.5 g/l) proved
increased stability:
MZVI in guar gum
MZVI in water
Sedimentation curves
16
8
Column tests: experimental
setup
Column transport tests:
Packed column:
□ L = 0.46 m, din = 2.5 cm, n = 0.49
□ Q = 6.74 ·10-4 l/s
Sand (Sibelco & Dorsilit):
□ d50 = 0.69 mm
□ Silica, K-feldspar (minor)
Particles (20 g/l):
□ MZVI (Basf)
□ NZVI (Toda Kogyo corp.)
Steps:
□ Injection (particles+dispersant)
□ Flushing (water)
Dispersant during injection:
□ Water (DI)
□ Xanthan (3 g/l) in DI or 12.5 mM
susceptimeter
manometer
OUT
column
IN
17
Column tests: experimental
setup
Column transport tests:
MZVI
Packed column:
d = 1.1 µm
□ L = 0.46 m, din = 2.5 cm, n = 0.49 c
Comp.: 98.4% Fe0
-4
□ Q = 6.74 ·10 l/s
0.69% C
Sand (Sibelco):
0.66% N
□ d50 = 0.69 mm
□ Silica, K-feldspar (minor)
Particles (20 g/l):
□ MZVI (Basf)
NZVI
□ NZVI (Toda Kogyo corp.)
dc = 70 nm
Steps:
Comp.: 35% Fe0
□ Injection (particles+dispersant)
65% Fe3O4
□ Flushing (water)
Dispersant during injection:
□ Water (DI)
□ Xanthan (3 g/l) in DI or 12.5 mM
18
9
Column tests: experimental
setup
Column transport tests:
INJECTION
MZVI or NZVI
Packed column:
+
□ L = 0.46 m, din = 2.5 cm, n = 0.49
□ Q = 6.74 ·10-4 l/s
water or xanthan 3 g/l
Sand (Sibelco):
(7 or 26 PVs)
□ d50 = 0.69 mm
□ Silica, K-feldspar (minor)
1
Particles (20 g/l):
□ MZVI (Basf)
0.8
□ NZVI (Toda Kogyo corp.)
0.6
Steps:
□ Injection (particles+dispersant)
0.4
□ Flushing (water)
Dispersant during injection:
0.2
□ Water (DI)
□ Xanthan (3 g/l) in DI or 12.5 mM 0
0
2000
FLUSHING
water
(26 or 15 PVs)
4000
6000
8000
19
Time (s)
Column tests: concentration
measurements
Iron concentrations measured with susceptibility sensors
Linear correlation between measured susceptibility and particle
concentration
□ Breakthrough curves
□ Total concentration profiles
Dalla Vecchia, E.; Luna, M.; Sethi, R. Transport in Porous Media of Highly Concentrated Iron Micro- and Nanoparticles in the Presence
of Xanthan Gum. Environmental Science & Technology 2009, 43(23), 8942-8947.
20
10
Column tests: experimental
results
Continuous in-line measurement of iron concentration at column outlet:
non destructive measurement
MZVI
NZVI
21
Column tests: experimental
results
Concentration profiles after injection (before flushing): non
destructive measurement
NZVI
MZVI
22
11
Modeling approach: key aspects
Key aspects:
1. Particle interactions with the porous matrix
□ Physical filtration/straining
□ Physical-chemical interactions: blocking, ripening
2. Clogging:
□ Influence of particle deposits on porous medium properties
□ Coupled problem
3. Viscosity of the dispersant fluid
□ Shear-thinning behavior
□ Darcy’s law for non-Newtonian fluids
23
Modeling approach: (1) Particleporous medium interactions
Modified ADE accounts for interaction mechanisms:
Straining
Blocking
Straining
First...
Ripening
physical-chemical
interactions
Clean bed
filtration/
straining
Then...
mechanisms
∂
∂ ( ρb s ) ∂
∂ 
∂c 
+ ( qm c ) −  ε m D  = 0
 (ε mc ) +
∂t
∂x
∂x 
∂x 
 ∂t

 ∂ ( ρb s )
= f ( c, s )
 ∂t
24
12
Modeling approach: (2) Clogging
Clogging: Deposited particles reduce porosity and
permeability:
g
g
V ,ε
g
g
V ,ε
↓ porosity
↑ surface area
ε m (s ) = n −
ρb
s
ρs
A(s ) = A0 + θAc
V ,ε
g
↓ permeability
g
K (s ) = C
ρb
s
ρc
n3
A2
Tosco, T.; Sethi, R. Transport of non-Newtonian suspensions of highly concentrated micro- and nanoscale iron particles in porous
media: a modeling approach. Environmental Science & Technology (submitted) 2010.
25
Modeling approach: (3) NonNewtonian viscosity
Xanthan or guar gum gel (shear-thinning)
→ non-Newtonian fluid
Cross model:
µ m = f (γ&m , c, c x )
Extended Darcy’s law:
qm = −
K (s )
∂p
µ m (γ&m , c, c x ) ∂x
Comba, S.; Dalmazzo, D.; Santagata, E.; Sethi, R. Rheological characterization of NZVI suspensions for injection in porous media.
Journal of Hazardous Materials (submitted) 2010.
26
13
Modeling approach: coupled model
E-MNM1D
http://areeweb.polito.it/ricerca/groundwater/software/EMNM1D.ht
ml
Model structure:
Darcy’s law
Transport
equations
Permeability
coefficient
Medium porosity
Fluid viscosity
Implementation:
Finite differences, 1D
Evolution of MNM1D model for colloid transport
Tosco, T.; Sethi, R. Transport of non-Newtonian suspensions of highly concentrated micro- and nanoscale iron particles in porous
media: a modeling approach. Environmental Science & Technology (submitted) 2010.
27
E-MNM1D:
www.polito.it/groundwater
Transport equations:
Darcy’s law:
∂
∂
∂
∂cx 
∂t (ε mcx ) + ∂x (qmcx ) − ∂x  ε m D ∂x  = 0



∂
∂(ρb s1 ) ∂(ρb s2 ) ∂
∂
∂c 
+
+ (qmc) −  ε m D  = 0
 (ε mc) +
∂t
∂t
∂x
∂x 
∂x 
∂t
∂(ρ s )
 b 1 = ε m ka,1 1+ A1s1β1 c − ρbkd ,1s1
 ∂t
β1

∂(ρb s2 ) = ε k 1+ x  c − ρ k s
m a,2 
b d ,2 2

 ∂t
 d50 

K (s )
∂p
qm = −
µm (γ&m , c, c x ) ∂x
(
Porosity:
ρb
s
ρs
ε m (s) = n −
)
Fluid viscosity:
µm (γ&m , c, cx ) = µm,∞ +
γ&m = αγ
µm,0 (c, cx ) − µm,∞
χm (c )
1 + [λm (c) ⋅ γ&m ]
qm
K (s)ε m (s)
Download:
Permeability:
2



3
A0
 ε (s ) 
 K
K (s ) =  m  
0

ρ
n

 A + ϑA b s 
c
 0

ρ

c 
www.polito.it/groundwater/software
1D
NM
M
E-
Tosco, T.; Sethi, R. Transport of non-Newtonian suspensions of highly concentrated micro- and nanoscale iron particles in porous
media: a modeling approach. Environmental Science & Technology 2010.
28
14
Modeling approach: information
from experimental data
1
Pressure drop
at column ends
0.8
0.6
clogging
&
viscosity
0.4
0.2
0
Outlet
particle
concentration
0
2000
4000
Time (s)
6000
8000
0
2000
4000
Time (s)
6000
8000
1
0.8
0.6
0.4
0.2
0
Concentration
profiles after
injection
Deposition
dynamics
4
3.5
3
2.5
2
1.5
1
0.1
0.2
0.3
x (m)
0.4
29
0.5
Modeling approach: fitting of
experimental data
MZVI
NZVI
Tosco, T.; Sethi, R. Transport of non-Newtonian suspensions of highly concentrated micro- and nanoscale iron particles in porous
media: a modeling approach. Environmental Science & Technology (submitted) 2010.
30
15
Permeability changes
Changes in permeability are manly due to changes in
surface area:
2



3
A0
 ε m (s )  
 K
K (s ) = 
0

 n   A + ϑA ρ b s 
c
 0
ρ c 

31
E-MNM radial and spherical
geometry
E-MNM (Enhanced Micro- and Nanoscale transport Model):
Homogeneous permeation;
Radial and spherical geometry.
Accounts for variable:
flow velocity
viscosity
attachment and detachment
coefficients
Unpublished data
32
16
Reagent delivery
(reactive zones)
Injection methods:
Gravity
Fracturing
□ Hydraulic
□ Pneumatic
Jetting
Pressure Pulse Technology
Direct push
Soil mixing
33
Direct push system
Hydraulicallypowered machines
Environmental
sampling (soil, gas,
groundwater)
Grouting and
reagents injection
www.carsico.it
34
17
Direct push system
Pumps and injection tips
High pressure (69-127 bar)
suitable for viscous fluids
Average pumping rates
Injection (Top-down or
bottom-up)
35
Recirculation
Sethi
36
18
Field injection of MZVI
FP7 AQUAREHAB
Injection 16/11/2011
Site description (Belgium):
Contamination of chlorinated hydrocarbons
Sandy-loam aquifer
Injection depth: 8.5 – 10.5 m
5 injection points
TCE
TCA
clayey sand
7m
coarse
sand
20m
37
Field injection of MZVI
Fracturing injection:
Direct push system (Geoprobe GS200)
High pressure bottom-up injection (10-40 bar)
Sospension:
MZVI: D
50
= 50
µm, 50 g/l
Guar gum: 6 g/l
Volume: 1.6 m
3
38
19
Field injection of MZVI
Installazione della rete di monitoraggio:
39
Conclusions
Stability:
Guar gum and xanthan (green biopolymers) provide thermodynamic and
kinetic stabilization:
□ MZVI: sedimentation prevention
□ NZVI: aggregation and sedimentation prevention
Transport in porous media:
Transportability: guar gum & xanthan increase breakthrough concentration
Modeling: successful modeling of particle transport with
□ Extension of Darcy’s law for non-Newtonian fluids
□ Changing of hydrodynamic parameters due to clogging
40
20
Projects and Acknowledgements
The work was partially funded by the EU Research
project (VII Framework Program) “AQUAREHAB –
Development of rehabilitation technologies and
approaches for multipressured degraded waters and the
integration of their impact on river basin management” –
project coordinator Dr. L. Bastiaens (VITO, Belgium)
Acknowledgement to:
DITAG, Politecnico di Torino: Alberto Tiraferri, Elena Dalla
Vecchia, Michela Luna, Francesca Gastone, Xue Dingqui, Silvia
Comba, Francesca Messina, Matteo Icardi
DISAT, Politecnico di Torino: Daniele Marchisio, Barbara Bonelli,
Federica Lince, Francesca Freyria
INRIM, Torino: Marco Coisson
41
References
Tosco T, Bosch J, Meckenstock RU, Sethi R. Transport of ferrihydrite nanoparticles in saturated porous media: role of
ionic strength and flow rate.Environ Sci Technol. 2012 Apr 3;46(7):4008-15
Freyria F.S.; Bonelli B.; Sethi R.; Armandi M.; Belluso E.; Garrone E. (2011). Reactions of Acid Orange 7 with Iron
Nanoparticles in Aqueous Solutions. In: JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND
INTERFACES, vol. 115 n. 49, pp. 24143-24152. - ISSN 1932-7447
Tosco, T.; Tiraferri, A.; Sethi, R. Ionic Strength Dependent Transport of Microparticles in Saturated Porous Media:
Modeling Mobilization and Immobilization Phenomena under Transient Chemical Conditions. Environmental Science &
Technology 2009, 43(12), 4425-4431.
Tosco, T.; Sethi, R. MNM1D: a numerical code for colloid transport in porous media: implementation and validation.
American Journal of Environmental Sciences 2009, 5(4), 517-525.
Tosco, T.; Sethi, R. Transport of non-Newtonian suspensions of highly concentrated micro- and nanoscale iron particles
in porous media: a modeling approach. Environmental Science & Technology (submitted) 2010.
Tiraferri, A., T. Tosco, e R. Sethi (2010), Transport and Retention of Microparticles in Packed Sand Columns at Low and
Intermediate Salinities: Experiments and Mathematical Modeling. Environmental Earth Sciences (submitted) 2010.
Tiraferri, A.; Chen, K.L.; Sethi, R.; Elimelech, M. Reduced aggregation and sedimentation of zero-valent iron
nanoparticles in the presence of guar gum. Journal of Colloid and Interface Science 2008, 324(1-2), 71-79.
Tiraferri, A.; Sethi, R. Enhanced transport of zerovalent iron nanoparticles in saturated porous media by guar gum. J
Nanopart Res 2009, 11(3), 635-645.
Dalla Vecchia, E.; Coisson, M.; Appino, C.; Vinai, F.; Sethi, R. Magnetic Characterization and Interaction Modeling of
Zerovalent Iron Nanoparticles for the Remediation of Contaminated Aquifers. Journal of Nanoscience and
Nanotechnology 2009, 9(5), 3210-3218.
Comba, S.; Dalmazzo, D.; Santagata, E.; Sethi, R. Rheological characterization of NZVI suspensions for injection in
porous media. Journal of Hazardous Materials (submitted) 2010.
Dalla Vecchia, E.; Luna, M.; Sethi, R. Transport in Porous Media of Highly Concentrated Iron Micro- and Nanoparticles in
the Presence of Xanthan Gum. Environmental Science & Technology 2009, 43(23), 8942-8947.
42
21