tomáš jiříček 15.2.2012. tomáš jiříček 15.2.2012
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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
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