3D characterization of asymmetric microfiltration membranes

Institute for Electron Microscopy and Fine Structure Research

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Herbert ReingruberArmin Zankel

May 30th, 2012

MicroPES®2F


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3D Visualization of the membrane structure

• Experimental Setup

• Results

Conclusion

• Sample Preparation

• Image Processing


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SEMHigh vacuum in the sample chamber

necessary

~ 10-4 Torr

ESEM

E(nvironmental) SEMadditional variable pressure range:

0.1 - 20 Torr


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ESEM Quanta 600 FA Microlab for Science and Industry

The Environmental Scanning Electron Microscope (ESEM)


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ESEM: Environmental SEM

LV-CSEM: Low Vacuum Conventional SEM

CSEM: Conventional SEM



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http://www.gatan.com/sem/3dmicrotomy.htmlhttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=524270


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Experimental setupin situ ultramicrotomy


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History: Stephen B. Leighton, 1981



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Preparation and Positioning of the Specimen

Embedding in resin, staining

Precutting with ultramicrotome

Positioning with light microscope and CCD-Camera



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First steps: paper


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resin

fibers

coat

Preparation:

Embedding in resin

No staining: intrinsicmaterial contrast

Precutting

First steps: paper


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100 cuts of a paper specimen (thickness of the slices: 200nm, micrograph: BSE) are assembled into a three dimensional (3D) model (unit: µm).

1. cut 100. cut50. cut

First steps: paper


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3D model of the fillerparticles of the paper 3D model of the fibers in the paper

First steps: paper


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20 µm

20 µm 20 µm

20 µm

roll sideair side

DuraPES®200

MicroPES®2F


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100 µm

0.5 mmDiamond knife

Sample mounted on the rivet


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Stack#2 (30.7 x 61.4 x 10.6) µm

approx. 150µm

Stack#1 (39.5 x 163.0 x 45.0) µm

10µm 10µm11.4µm

10µm 10µm 10µm 3.6µm

10µm10µm 10µm

Stack #1

Stack #2 Stack #3

a b

c d

Stack#3 (37.5 x 25.6 x 10.0) µm

DuraPES®450


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10µm 10µm11.4µm10µm10µm 10µm

a b[µm]

[µm]

[µm]


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a b c d

0

[µm]

[µm]

10

10

a30

[µm]

5

5

1020

[µm]

0

10

10

b30

[µm]

5

5

1020

[µm]

[µm]

0

10

10

c25

[µm]

5

5

12,5

[µm]

[µm]

0

8

10

d25

[µm]

5

4

12,5[µm]


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10µmsurf

ace

A(a

ir si

de)

surf

ace

A(a

ir si

de)

surf

ace

A(a

ir si

de)

10 µm 10 µm10 µm

MicroPES®4F DuraPES®450 Sartorius 15406


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specifically measured


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MicroPES®4Fair side

DuraPES®450 Sartorius 15406

roll side

5 µm 10 µm

3Dre

cons

truct

ions

3Dre

cons

truct

ions

SEM

imag

esSE

Mim

ages

air side air side

roll side roll side

5 µm

5 µm 5 µm 5 µm


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3D reconstruction SEM image


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Resultssub porous structure


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3D model of the membrane structure

Calculation of the pure water flux

Calculation of the absolute permeability


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with

Ohm‘s Law:

Calculation of the pure water flux: some equationspA

pB

A

l

Q Q

Darcy´s Law:


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10µmsurf

ace

A(a

ir si

de)

surf

ace

A(a

ir si

de)

surf

ace

A(a

ir si

de)

10 µm 10 µm10 µm

MicroPES®4F DuraPES®450 Sartorius 15406


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specifically measured


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• 3D reconstructions reproduce the surface morphology, the pore structures etc.

• The gained parameter profiles give quantitative values of the inner pore structure

• The results of the fluid simulations are in agreement with the experiment


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[4] H. Reingruber, A. Zankel, C. Mayrhofer, and P. Poelt. Quantitative characterization of microfiltration membranes by 3D reconstruction.

J.Membr.Sci. 372 (2011) 66‐74.

[1] W. Denk, H. Horstmann. Serial Block‐Face Scanning Electron Microscopy to Reconstruct Three‐Dimensional Tissue Nanostructure.

PLoS Biol, 2 (2004) e329.

[3] R. Ziel, A. Haus, and A. Tulke. Quantification of the pore size distribution (porosity profiles) in microfiltration membranes by SEM, TEM and computer image analysis.

J.Membr.Sci., 323 (2008) 241.

[2] M. Ulbricht, O. Schuster, W. Ansorge, M. Ruetering, and P. Steiger. Influence of the strongly anisotropic cross‐section morphology of a novel polyethersulfone microfiltration membrane on filtration performance.

Separation and Purification Technology, 57 (2007) 63.


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Ing. Claudia Mayrhofer PD Dipl.-Ing. Dr. Peter Pölt


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Thank you for your attention!Time for Discussion

Dipl.-Ing. Herbert Reingruber

Documents

3D characterization of asymmetric microfiltration membranes