Transport of Small Molecules in Polymers:
Overview of Research Activities
Benny D. Freeman
Department of Chemical Engineering University of Texas at
Austin,
Office: CPE 3.404 and CEER 1.308B
Tel.: (512)232-2803, e-mail: [email protected]
http://www.che.utexas.edu/graduate_research/freeman.htm
http://membrane.ces.utexas.edu
1
Freeman Research Group Focus
Develop fundamental structure/function rules
to guide the preparation of high performance
polymers or polymer-based materials for gas
and liquid separations as well as barrier
packaging applications.
Freeman Research Group Profile
• 15 Ph.D. students:
– Gas Separations: Qiang Liu, Kevin Stevens, Grant Offord, Tom
Murphy, Katrina Czenkusch, David Sanders, Zach Smith*
– Liquid Separations: Wei Xie, Dan Miller*, Joe Cook, Geoff Geise,
Michelle Oh, Albert Lee, Peach Kasemset*
– Barrier Materials: Kevin Tung
• 2 Postdocs: Dr. Claudio Ribeiro*, Dr. Chaoyi Ba
• Sponsors:
– NSF - 5 projects
– DOE – 2 projects
– Office of Naval Research - 1 project
– Industrial sponsors: PSTC, Air Liquide, Kuraray, Kraton
Polymers, ConocoPhillips, Statkraft, Dow Water Solutions
* = group members who have won major fellowships to support
their work from either the US govt. (NSF, DOE) or their home govt.
Recent Graduates (within last 18 months)
Student
Employer
Area (Ph.D./Work)
Dr. Alyson Sagle
Air Products, St. Louis, MO
Fouling-resistant membranes/Gas
separation membranes
Dr. Yuan-Hsuan Wu
Intel, Portland, OR
Fouling-resistant
membranes/Microelectronics
Dr. Victor Kusuma
Los Alamos (postdoc)
Gas separation membranes
Dr. Lauren Greenlee
NIST (postdoc), Boulder, CO
High recovery desalination
membranes/Nanoparticles in water
treatment
Dr. Bryan McCloskey
IBM (postdoc), San Jose, CA
Fouling-resistant
membranes/Batteries
Dr. Hao Ju
Dow, Midland, MI
Fouling-resistant membranes/Battery
separators
Dr. Brandon Rowe
NIST (postdoc), Gaithersburg, MD
Physical aging in gas separation
membranes/Polymer physics of
membranes
Dr. Liz van Wagner
GE Global Research, Niskayuna,
NY
Fouling-resistant
membranes/Membranes
Dr. Richard Li
Advanced Hydro, Inc.
Fouling-resistant membranes
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Current Projects - 1
• Gas Separations
• Thermally-Rearranged Polymers for Gas
Separation
• CO2/CH4 Separation for Natural Gas Purification
• Physical Aging in Glassy Polymers
• Physical Aging in Microlayered Polymers
• CO2/O2 Separation for Food Packaging
Applications
• Melt Processing Strategies to Prepare Thin
Membranes for Gas Separations
• Bioethanol Purification (Ethanol/Water Separation)
Current Projects - 2
• Liquid Separations
• Chlorine-Tolerant Desalination Membranes
• Desalination Membranes Based on Novel Block
Copolymers
• Fundamental Studies of Ion and Water Transport in
Polymers
• Melt Processing Strategies to Prepare Desalination
Membranes
• Bio-inspired Surface Modification of Water Purification
Membranes to Improve Fouling Resistance
Current Projects - 3
• Others
• Fundamental Studies of Oxygen Scavenging Polymers
for High Oxygen Barrier Packaging
• Hydrocarbon/Hydrocarbon Pervaporation for Refinery
Separations
Fouling: A Major Limitation in Liquid
Filtration Membranes
100
1 g/L BSA solution, pH=7.4
0.3 gpm crossflow, P=10.2 atm
0.2 m PVDF membrane
10
2000x
decrease
-2
External
fouling
-1
-1
Permeance [L m h kPa ]
Feed flow
Internal
fouling
1
0.1
Membrane
0.01
0
5
10
Time [h]
8
15
20
Mimicking Mussel Adhesion (“Bio-Glue”)
N
HO
NH 2
HO
HO
Dopamine
9
H. Lee, S.M. Dellatore, W.M. Miller, and P.B. Messersmith., Mussel-Inspired
Surface Chemistry for Multifunctional Coatings. Science, 318, 426-430 (2007).
OH HO
Polyd
Polydopamine: Novel Fouling Resistant
Membrane Coating
Polydopamine
10
Polydopamine as Surface “Primer” to Graft
PEG to Membrane Surfaces
Proposed Polydopamine Structure:
O
N
O
H
PEG ad-layer
O
H2N
CH3
n
Michael Addition/
Schiff Base Reaction
Polydopamine
PEG
HN
O
N
H
11
Oily Water Filtration Using Pegylated Polydopamine
Treated Teflon Microfiltration Membranes
160
PDOPA-g-PEG modified
(94.5% rejection)
PTFE MF
-2 -1
Flux [Lm h ]
140
120
PDOPA modified
(95.7% rejection)
100
80
Unmodified (85.4% rejection)
0
0.2
0.4
0.6
0.8
1
Time [h]
Modification: 60 min PDOPA deposition time followed by 60 min 5KDa PEG-NH2 (1mg/mL, 60 °C)
Conditions: P=0.3 atm, crossflow=120 L/h (Re=2500) 1500 ppm soybean oil/DC193water emulsion (non-ionic)
12
Field Validation - Visual
- Two identical UF PAN membranes
-
-
that are highly hydrophilic
One coated and one non-coated,
both processed high fouling water
stream from a bio-reactor with a lot
of sludge.
10 minute filtration followed by 1
min backwash cycle for 48+ hours.
Both membranes were taken out
and flushed with a hose / water
- Modified membrane washes clean
- Non-modified retains sludge film
- Membrane housings (hydrophobic)
also showed significantly better
anti-stick, fouling resistant surface
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Field Validataion: Ultrafiltration of Bioreactor
Effluent
Unmodified
Modified
2X More Water
Processed Between
Cleanings
40% Lower Energy
- Pressure increases during single filtration/back-flush cycle due to fouling
- Almost twice the volume of water could be processed for same end-point pressures
- Unmodified shows pressure increase at a rate of 1.55 psi/hr vs. 1.1 psi/hr for modified membrane
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Natural Gas Processing
• 100 trillion scf of natural
gas used worldwide per
year
– All requires pretreatment
• Amine absorption is the
leading technology
• Membranes have < 5%
market share
R.W. Baker, K. Lokhandwala, Natural gas processing
15 with membranes: An overview,
Industrial & Engineering Chemistry Research. 47 (2008) 2109-2121.
Science, vol. 318, 12 October 2007, pp. 254-258.
CO2/CH4 Separation Performance
OH
HO
O
N
O
O
CF3
CF3
N
F3 C
CF3
O
1: PIOFG-1
2: TR-1-350
3: TR-1-400
4: TR-1-450
5-19: OTHER TR POLYMERS
H.B. Park, C.H. Jung, Y.M. Lee, A.J. Hill, S.J. Pas, S.T. Mudie, E. van Wagner, B.D.
Freeman, & D.J. Cookson, Polymers with Cavities Tuned for Fast, Selective
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Transport of Small Molecules and Ions, Science, 318, 254-258 (2007).
Cavity Size Distribution from Positron
Annihilation Lifetime Spectroscopy
OH
HO
O
(c)
N
Relative intensity (a.u.)
O
(d)
(b)
O
CF3
CF3
N
F3 C
CF3
O
(a) PIOFG-1
(b) TR-1-350
(c) TR-1-400
(d) TR-1-450
(a)
2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
o
Cavity radius (A)
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Beating the Permeability-Selectivity Tradeoff
for H2 Purification
Lin et al., Science, 311, pp. 639-642 (2006).
Reduction to Practice
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CO2 Selective Materials
Using Nanocomposites to Enhance Membrane Separations
Using Nanolayering to Enhance Gas Barrier Properties