Studying Zeolitic Diffusion by Interference and IR...

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)