studying zeolitic diffusion by interference and ir...
TRANSCRIPT
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
Studying Zeolitic Diffusion by Interference and IR Microscopy
Studying Zeolitic Diffusion by Interference and IR Microscopy
Jörg KärgerSergey Vasenkov (Gainesville, University of Florida)
Pavel Kortunov (Exxon-Mobil)Christian Chmelik
DB Shah (Cleveland University)Lars Heinke
Despina Tzoulaki
Project 5
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
What do we measure?What do we measure?
Pulsed Field Gradient (PFG) NMR
<r2(t)> = 2D tr(t)
self-diffusion
Interference Microscopy (IFM)
j = – D(T) grad c j
transport diffusion
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
Adsorption system and cyclesAdsorption system and cycles2. Preparation for adsorption1. Pumping / Activation
T=4000C
3. Adsorption4. Preparation for desorption
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
IFM TechniqueIFM Technique
Spatial resolution: 0.5 μm × 0.5 μm
L
0)0(
2ϕ)0(1ϕ
)(1
Lϕ )(2
Lϕ0)( ≠Δ Lϕ
0)0( =Δϕ
Δφ ~ Δn ~ Δc
n1 n2
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
OutlineOutline
y
xz
(a) 1-D pore structure of the MOF crystals
(b) 2-D pore structure of the Ferrierite zeolite
z
y
x
Dy
Dx
Dz
(c) 3-D pore structure of the SAPO STA-7
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
(*) D.N. Dybtsev, H. Chun, S.H. Yoon, D. Kim and K. Kim; J. Am. Chem. Soc., 2004, 126, 32-33
y
xz
1-D pore structure of MOF crystal (*)
0 20 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
Methanol adsorption 0 → 10 mbar into MOF crystal
√t , s1/2
Rel
ativ
e co
ncen
tratio
n
fitting by diffusion resistance model
Davarage = 1.05 × 10-12 m2/s
Macroscopic adsorption techniques:
Interference microscopy technique:
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
0 10 20 30 40 500.0
0.2
0.4
0.6
0.8
1.0
gas
phas
e ou
tsid
e of
the
crys
tal
gas
phas
e ou
tsid
e of
the
crys
tal
space of the crystal
400 sec
310 sec
250 sec
190 sec
130 sec
70 sec
50 se
c
Δ(Δc/Δx)/Δx
Δc/Δt
Δc/Δx
10 se
c
Methanol adsorption into MOF crystal
x , μm
Con
cent
ratio
n
before 0 sec
ceq- c(t)
y
xz
Surface PERMEABILITY
46 48 50 520.7
0.8
0.9
1.0
Con
cent
ratio
n
x , μm
ceq- c(t)
Δc/Δx ≈ dc/dx
3 6 9 12 150.3
0.4
0.5
0.6
0.7
Con
cent
ratio
n
x , μm
Δ(Δc/Δx)/Δx ≈ d 2C/dx 2
Δc/Δt ≈ dC/dt
Local DIFFUSION
First and second Fick‘s laws
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
1-D diffusion in the MOF crystal
Local DIFFUSION(microscopic analysis)
πDta
cccct 2
0
0 ≈−−
∞
Average DIFFUSION(macroscopic analysis)
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
OutlineOutline
y
xz
(a) 1-D pore structure of the MOF crystals
(b) 2-D pore structure of the Ferrierite zeolite
z
y
x
Dy
Dx
Dz
(c) 3-D pore structure of the SAPO STA-7
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
2-D pore structure of Ferrierite crystals
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
Directions of methanol adsorption in Ferrierite crystal
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
Fick’s Second Law:
0 10 20 30 40 50
0.0
0.2
0.4
0.6
0.8
1.0
t = 2250 sec
t = 1650 sec
t = 1100 sec
t = 750 sec
t = 400 sec
t = 230 sec
t = 110 sec
t = 30 sec
Δ(Δc/Δx)/Δx
M
olec
ular
con
cent
ratio
n
y, μm
Adsorption of Methanol (0 → 5 mbar) into Ferrierite
Δc/Δt
t = 0 sec5 10 15
0.2
0.4
0.6 Δ(Δc/Δx)/Δx ≈ d 2c/dx 2
Δc/Δt ≈ dc/dt
Fick’s First Law:x = 24 μm
Local diffusion and surface resistance
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
0.0 0.2 0.4 0.6 0.8 1.010-13
10-12
10-11
0.0 0.2 0.4 0.6 0.8 1.0
10-3
10-2
10-1
100
Desorption 5 → 0 mbar Desorption 10 → 0 mbar
Desorption of Methanol from Ferrierite
Diff
usiv
ity ,
m2 s-1
Norm. concentration
P
erm
eabi
lity
×10-6
, m s
-1
0 10 20 30 40 50
0.0
0.2
0.4
0.6
0.8
1.0
experimental points calculation using D(c) and α(c)
t = 1950 sect = 1350 sec
t = 900 sec
t = 600 sec
t = 400 sec
t = 3450 sect = 7350 sec
t = 210 sec
t = 90 sec
t = 30 sec
y , μm
Desorption Methanol (10 → 0 mbar) from Ferrierite
Con
cent
ratio
n
beforet = 0 sec
TESTLocal DIFFUSION
Concentration dependence of the molecular diffusivity
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
y
xz
(a) 1-D pore structure of the MOF crystals
(b) 2-D pore structure of the Ferrierite zeolite
z
y
x
Dy
Dx
Dz
(c) 3-D pore structure of the SAPO STA-7
OutlineOutline
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
3-D pore structure of STA-7 materials (*)
z
y
x
Dy
Dx
Dz
(*) Paul A. Wright, Martin J. Maple et al., J. Chem. Soc., Dalton Trans., 2000, 1243–1248
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
3-D pore structure of STA-7 materials
z
y
x
Dy
Dx
Dz
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
0 5 10 15 20 25
0.0
0.2
0.4
0.6
0.8
1.0
C(y
)=∫ C
(x,y
,z20
μm) d
x
t = 70 sec
before adsorptiont = 0 sec
y , μmx , μm
y , μm
22.5
0 22.5
t = 70 sec
Uptake in y- and x-directions
z
y
x
0 5 10 15 20 25
0.0
0.2
0.4
0.6
0.8
1.0
before adsorptiont = 0 sec
C(y
)=∫ C
(x,y
,z20
μm) d
x
t = 10 sec
y , μmx , μm
y , μm
22.5
0 22.5
t = 10 secjy
jx
0 5 10 15 20 25
0.0
0.2
0.4
0.6
0.8
1.0
C(y
)=∫ C
(x,y
,z20
μm) d
x
before adsorptiont = 0 sec
y , μmx , μm
y , μm
22.5
0 22.5
t = 0 sec
0 5 10 15 20 25
0.0
0.2
0.4
0.6
0.8
1.0
before adsorptiont = 0 sec
C(y
)=∫ C
(x,y
,z20
μm) d
x
t = 30 sec
y , μmx , μm
y , μm
22.5
0 22.5
t = 30 secjy
jx
0 5 10 15 20 25
0.0
0.2
0.4
0.6
0.8
1.0
C(y
)=∫ C
(x,y
,z20
μm) d
x
equilibriumt = 18 min
t = 350 sec
t = 170 sec
t = 30 sec
t = 70 sect = 50 sec
t = 10 sec
before adsorptiont = 0 sec
y , μm
Package of Research Projects ”Diffusion in Zeolites”by CNRS (France), DFG (Germany), EPSRC (United Kingdom), NSF (USA)
Extension for the Period from 2006-2009
thermo isolated box
IFM perspectives…IFM perspectives…
P2
P1
vacuumpump
ampoulewith liquid
large tank
optical cell
additionalentrance
interference microscope
thermo isolated box
heater/cooler
Tmax = 1000C (2040C)
Tmin = 00C (-500C)