Adnan Alam (1)

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7/27/2019 Adnan Alam (1)

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7/27/2019 Adnan Alam (1)

Fabrication of Nano porous

membrane for Ultra filtration

Supervised by: Dr. M. Mujahid

ADNAN ALAM

MS MATERIAL AND SURFACE

ENGINEERING

REG#2011-NUST-MS PhD-MS-E-02

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Contents

Phase Inversion Process

Membrane Fabrication

SEM Results AFM Results

FT-IR Results

XRD Results

De-Ionized water Flux Results

Future Work

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Phase Inversion Process

Liquid Liquid Phase Inversion

Mass transfer takes place, i.e. the

solvent from the polymer solutiondiffuses into the precipitation bath,

whereas the non-solvent diffuses into

the polymer solution. Thus, solution

composition is changed which takes to

a de-mixing process.

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Pore Formation Mechanism

The polymer solution in solvent results inhomogenous polymer-solvent solution.

When this solution in exposed in

precipitation bath containing non-solvent,exchange between solvent and non-

solvent takes place.

Solvent leaves polymer solution creatingvoids while non-solvent diffuses in

polymer, precipitating it into membrane

structure. 6

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Membrane Modules

UF membrane modules are

Tubular Hollow-fiber

Spiral wound configurations

Flat sheet

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Materials for Membrane

Polymer (Cellulose Acetate)

Pore gen (Chitosan)

Solvent (Formic Acid)

Non-solvent (Water)

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Limitations of Cellulose Acetate

Membrane

Thermal stability

Poor film making properties Mechanical properties

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Improvement in CA by Chitosan

Hydrophilic properties increase

Mechanical strength and mechanical

toughness increase

Anti bacterial activity

Excellent film forming ability

Chitosan non-toxic Chitosan as crosslinking agent

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BLEND RATIO

Cellulose Acetate: Chitosan: Formic Acid

10 : 3 : 150

Cellulose Acetate =1gm

Chitosan = 0.3 gm

Formic Acid = 15 ml

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Cellulose acetate based

membrane

Cellulose acetate (CA) and Chitosan

Formic Acid

Constant stirring

De-aeration

casting on glass

Solvent Evaporation

Non-solvent addition

Membrane drying

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Casting & Blending

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Solution To Avoid Membrane

Shrinkage

Method # 1 Method # 2

1. Membrane immersion

in aqueous isopropylalcohol solution for 24

2. Immersion in a mixture

of isopropyl alcohol andhexane solution for 24

3. Immersion in pure

Hexane and than dryingin desiccators.

Drying in desiccators

keeping membranestretched.

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SEM RESULTS(Air dried

membrane)

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SEM RESULTS(Air dried

membrane)

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Cont…

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Cont…

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(Solvent dried membrane)

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Cont…

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Cont…

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Cont…

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Cont…

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Cont…

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Cont…

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SEM Conclusions

Membrane is porous

Uniform distribution of pores

Pore size ranges in UF limits (10-

100nm)

Reproducibility of results

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AFM (Air dried membrane)

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AFM (Solvent dried

membrane)

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Conclusions of AFM

Pore diameter confirmation

Surface Roughness Presence

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Comparison of AFM & SEM

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Structure Of Cellulose Acetate

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Structure Of Chitosan

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0 500 1000 1500 2000 2500 3000 3500 4000 4500

T r a n s m i t t a n c e %

Wave number(cm-1)

cellulose acetate

0 500 1000 1500 2000 2500 3000 3500 4000 4500

wave number(cm-1)

Chitosan

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500 1000 1500 2000 2500 3000 3500 4000

wave number (cm-1

membrane

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Comparison

500 1000 1500 2000 2500 3000 3500 4000

Wave number (cm-1)

cellulose acetate

membrane

Chitosan

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Conclusion Of FT-IR

The absorption peaks in FTIR spectrum of cellulose

acetate is attributed to the vibrations of the acetate group

1790 cm-1 (C=O),

1370 cm-1 (C-CH3),

and 1045 cm-1 (C-O-C).

The FTIR spectrum of Chitosan is characterized by

absorption bands at 3352 (-OH stretching),

2878 cm-1 (-CH3 stretching),1560 (N-H bending),

1404 cm-1 (-OH bending),

1077 cm-1 (C-O bending),

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Cont…

All prominent peaks in both cellulose acetate and

Chitosan are present in membrane spectrum,

also broad hydroxyl peak in cellulose acetate

become narrow and shift in Position.

Therefore, these changes in the IR spectra

suggested that there is homogenous blending

between Chitosan and cellulose acetate inmembrane.

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10 15 20 25 30 35 40

I n t e n s i t y

Thetea

Cellulose acteate

10 15 20 25 30 35 40

I n t e n

s i t y

Thetea

Chitosan

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10 15 20 25 30 35 40

I n t e n s i t y

Thetea

Membrane

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10 15 20 25 30 35 40

i n t e n s i t y

Thetea

Membrane

Cellulose acteat

Chitosan

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Conclusions of XRD

XRD pattern of Chitosan exhibited characteristiccrystalline reflections at approximately 21 θ .

Cellulose acetate XRD spectrum indicates an obvious

broad peak at 22 θ and this peak verified that Celluloseacetate had denser semi crystalline structure.

In XRD spectrum of membrane, both above mentioned

characteristics peaks of Chitosan and cellulose acetateshifts their position along with intensity. This change

clearly confirms successful blending of both Chitosan

and cellulose acetate in membrane

P it C fi ti b Fl

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Porosity Confirmation by Flux

Water flux was measured by

Jw = Q/A . ∆t

Q: Amount of permeate

A: Area of membrane

∆t: Time of sampling

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0.01 10.3 0.0103 0.00422 2.440758 0.01666666 146.445556

0.02 24.5 0.0245 0.00422 5.805687 0.01666666 348.341372

0.03 41.1 0.0411 0.00422 9.739336 0.01666666 584.360423

0.04 48 0.048 0.00422 11.37441 0.01666666 682.464728

0.05 74.9 0.0749 0.00422 17.74882 0.01666666 1064.92934

0.01 0.02 0.03 0.04 0.05

f l u x ( L / m 2 h r )

Pressure(bar)

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0.01 10.1 0.0101 0.00422 2.393365 0.01666666 143.601953

0.02 23.9 0.0239 0.00422 5.663507 0.01666666 339.810562

0.03 40.7 0.0407 0.00422 9.64455 0.01666666 578.673217

0.04 54.7 0.0547 0.00422 12.96209 0.01666666 777.72543

0.05 76.3 0.0763 0.00422 18.08057 0.01666666 1084.83456

0.01 0.02 0.03 0.04 0.05

f l u x ( L / m 2 h r )

Pressure(bar)

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0.01 17.8 0.0178 0.00422 4.218009 0.01666666 253.08067

0.02 24.9 0.0249 0.00422 5.900474 0.01666666 354.028578

0.03 31.3 0.0313 0.00422 7.417062 0.01666666 445.023875

0.04 37.4 0.0374 0.00422 8.862559 0.01666666 531.753767

0.05 44 0.044 0.00422 10.42654 0.01666666 625.592667

0.01 0.02 0.03 0.04 0.05

f l u x ( L / m 2 h r )

Pressure(bar)

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0 0.01 0.02 0.03 0.04 0.05 0.06

flux(L/m2 hr) 11feb

flux(L/m2 hr) 13 feb

flux(L/m2 hr) 14feb

Pressure (bar)

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Future Work

Optimization of the process by varyingthe Chitosan content.

Waste water treatment/ proteinrejection and results analysis

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Adnan Alam (1)

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