Vliv nanovlákenné struktury na proudění filtračních medií

Tomáš Jiříček15.2.2012

The Effect of NanoFibre Structure on Filtration Flow

Tomáš Jiříček15.2.2012

Outline

About My PhD About Filtration Membrane Characterisation Testing Considerations and

Equipment Area of Research First Results Acknowledgements

My PhD Interest

Development and testing of composite (ultrafiltration) membranes with nanofibre structures,

and nonwoven nanofibre membrane filter media with high permeability (low transmembrane pressure), containing chemically and biologically active components.

Separation Processes

Mass force on freely moving particles: Sedimentation Flotation Coagulation and floculation

Particles blocked and liquid flows through Filtration

Filter medium

Any material, that under the operating conditions, is permeable to one or more components of a mixture, solution, or suspensions, and is impermeable to others. (Sutherland and Purchas, 2002)

Classification

Driving force – pressure upstream Mechanism – cross-flow Objective – clarified liquid Operating cycle – constant rate Nature of solids – compressible

Membrane Characterisation

Permeability (pore size and density, thickness) Water flux in dead-end flow

Retention (MWCO molecular weight cut-off) molar mass of the globular protein which

is 90% retained by the membrane

Concentration Polarization Retained macro-

solutes form a second membrane on the surface.

Restriction of flow and changes of selectivity

Flux without response to pressure Kaushik Nath. Membrane Separation Processes. PHI

Learning, 2008

Fouling and Biofouling

Major concern – flux decrease Changes membrane properties Fouling and concentration polarization additive

resistance Fouling prevention is very important

selection of membrane operating conditions feed pretreatment start-up techniques cleaning type and frequency

Interesting competition between: stable hydrophobic membranes less fouling hydrophilic membranes

Cross-Flow Filtration

http://www.winebusiness.com

• Feed recirculated with high velocity parallel to the filter.• Cake continuously removed from the membrane surface.• High permeate flux due to minimal particle deposition

Testing

Testing conditions vs real life conditions

Typically: holding capacity, pressure drop, time dependency, and filtration efficiency Percentage of contaminant removed Filtration efficiency (99%) vs penetration

(1%)

Considerations

Fluid properties (viscosity, temperature, chemical properties)

Contaminant properties (PSD, concentration)

Desired performance: Filtration Efficiency Flow resistance Filter life Size

↘particle size ↘ fibre diameter ↗ COST

Theory and Scale-up

Filtration theory in literature overwhelming

Large scale equipment cannot be designed without small-scale tests

Correlations for scale-up acc. to filtration theory Constant pressure Constant rate

Perfect Filter ???

Perfect Filter ???

Removes all contaminants No restrictions, ∆p = 0 Infinite holding capacity, lasts

forever Infinitely small Costs nothing

Cross-Flow Testing on AlfaLaval M10

4 Micro and Ultrafiltration membranes 336 cm2 each operating in series Concurrent test of different membranes Flow pattern similar to large-scale devices Test results were extremely reliable for scale-up Single pass mode, Batch mode, Constant volume mode

© AlfaLaval

Areas of Research in Cross-Flow

Characterisation and testing of membranes

Study of process characteristics Intensification of the process and

scale-up Separation of biological materials in

waste-water treatment applications Mathematical modeling

Area of Research – Part 1

Development and testing of composite ultrafiltration membranes with nanofibre structures Permeability Long term performace Leaching of added chemicals Antibacterial properties

Area of Research – Part 2 Development and testing of nonwoven

nanofibre membrane filter media with: low transmembrane pressure (operation cost) chemically / biologically active components

Dense nanofibre layer to avoid depth filtration

Long term operation Resistance to (bio)fouling Change of filtration parametres with time

Waste water treatment – remove „unremovable“, membranes for MBR

Composite membranesANTIBACTERIAL PROPERTIES

No colonies Nadir UP150 PES AgNO3 Cont Elspin

3 coloniesNadir UP150PUR AgNO3

Hand Elspin

25 coloniesNadir UP150PES AgNO3 Hand Elspin

1000 coloniesNadir UP150PES Ag beh. Cont Elspin

Composite membranes (UP150/PUR/AgNO3)

PERMEABILITY

w/o lamination 90 100 110

1 layer permeabil-ity

283.393160778387

255.863539445629

149.253731343284

93.2835820895522

2 layer permeabil-ity

283.393160778387

201.240986080832

149.752907702291

114.079285103147

25.0

75.0

125.0

175.0

225.0

275.0

Lamination temperature decreases permeability

perm

eabilit

y [

l/m

2.h

.bar]

Composite membranesLEACHING OF SILVER

0 5 10 15 20 25 30 350.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

Leaching of silver from nanofibre layer 2011/12

Filtrate volume [ml]

Conc

Ag [

mg/l]

• Typically leaching is continous and decreasing• Total of 0,02 mg Ag washed out in the first 30 ml

(app. 2%)

Acknowledgements

Tomáš Lederer Lenka Martinová Jakub Hrůza Alice Břečková Jan Dolina

Thank you

BACK-UP SLIDES

Analytical methods to monitor endocrine disruptors

Short chain alkylphenols – GC-MS Long ethoxylate chains – HPLC

fluorescence Hormones – HPLC + MS-MS

GC + (MS-MS) on the way

Single Pass Operation

Particle contaminant in the fluid passes through the filter once

Batch Operation

Constant Volume Operation

Pressure and Flowrate

Particle Spectrum

© Filtration and Separation Spectrum, 2007 GE Company