MEMBRANE CHARACTERIZATION

ASEP MUHAMAD SAMSUDIN, S.T.,M.T.

MEMBRANESEPARATION

SCANNING ELECTRON MICROSCOPY (SEM)

• SEM is very simple and useful techniques for characterizing structure and morphology of membrane.

• A clear and concise picture of the membrane can be obtained in terms of the top layer, cross-section and bottom layer.

• Magnification in a SEM can be controlled from about 10 to 500,000 times

• The porosity and the pore size distribution can be estimated from the photographs.

• Care must be taken that the preparation techniques does not influence the actual porous structure.

Source : http://en.wikipedia.org

SCANNING ELECTRON MICROSCOPY (SEM)

First Scanning Electron Microscope with high resolution from Manfred von Ardenne 1937 Source : www.ceo.msu.edu

Source : http://en.wikipedia.org

SCANNING ELECTRON MICROSCOPY (SEM)

Flat Sheet Hollow Fiber

PERMEABILITY

• With this method, the pore size can be obtaining by measuring the flux through a membrane at a constant pressure using the Hagen-Poiseuille equation

• Hagen-Poiseuille equation

Retentate

Permeate

Feed

membrane

Cross-flow process

PERMEABILITY

Dead-End process

Source : www.sciencedirect.com

FOURIER TRANSFORM INFRARED SPECTROSCOPY

Source : www.ssi.shimadzu.com

• In membrane characterization, FTIR is used to determine the chemical composition of the membrane

• IR radiation is passed through a sample. Some of the infrared radiation is absorbed by the sample and some of it is passed through (transmitted)

• Infrared spectroscopy can result in a positive identification (qualitative analysis) of every different kind of material. In addition, the size of the peaks in the spectrum is a direct indication of the amount of material present.

• Fourier Transform Infrared (FT-IR) spectrometry was developed in order to overcome the limitations encountered with dispersive instruments.,

FOURIER TRANSFORM INFRARED SPECTROSCOPY

400600800100012001400160018002000240028003200360040001/cm

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Abs

3450

.65

3419

.79

3385

.07

2933

.73

2872

.01

2358

.94

1647

.21

1560

.41

1535

.34

1375

.25

1319

.31

1259

.52

1238

.30

1199

.72

1151

.50

1068

.56

1033

.85

898.

83

663.

51 617.

22

Kitosan Medium 2 gr Aktivasi GA 1%600750900105012001350150016501800195021002400270030003300360039001/cm

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

Abs

15

75

.84

15

58

.48

14

87

.12

12

94

.24

12

42

.16

11

51

.50

11

05

.21

10

47

.35

87

1.8

2

83

7.1

1

71

7.5

26

98

.23

66

5.4

4

62

6.8

7

55

9.3

6

51

8.8

5

PES UF

BUBBLE POINT METHOD

• This method is a very simple technique for characterizing the largest pores in microfiltration membrane.

• The method essentially measure the pressure needed to blow air through a liquid-filled membrane.

• The top of the membrane is placed in contact with a liquid which fills all the pores when the membrane is wetted. The bottom of membrane is in contact with air and as the air pressure is gradually increased bubbles of air penetrate through the membrane at a certain pressure.

• The relationship between pressure and pore radius is given by the Laplace equation.

• A disadvantages is that different results are obtained when different liquids are used for characterization.

BUBBLE POINT METHOD

SOLUTE REJECTION TEST (MWCO)

• This method is very frequently used for the industrial assessment membrane.

• This method is often referred to as challenge test or sieving test.• In this method, permeability of solute (macromolecule) that used for

membrane test is measured in certain condition. • Membrane rejection was calculated using the equation

• Pore size is expressed by the molecular weight cut off which is defined as the molecular weight that 90% rejected by membrane.

SOLUTE REJECTION TEST (MWCO)

Solute BM

D-AlanineDL-PhenylananineTryptophanSucroseRaffinoseInulinPVP K15Dextran T10MyoglobinΑ-ChymotrypsinogenAlbuminAldolaseLgApoferitinlgM

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