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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
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 Focus
• 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
Freeman Research Group Profile
* = group members who have won major fellowships to support
their work from either the US govt. (NSF, DOE) or their home govt.
4
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
• 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 - 1
• 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 - 2
• Others
• Fundamental Studies of Oxygen Scavenging Polymers
for High Oxygen Barrier Packaging
• Hydrocarbon/Hydrocarbon Pervaporation for Refinery
Separations
Current Projects - 3
8
0.01
0.1
1
10
100
0 5 10 15 20
Perm
eance [
L m
-2 h
-1 k
Pa
-1]
Time [h]
1 g/L BSA solution, pH=7.4
0.3 gpm crossflow, P=10.2 atm
0.2 m PVDF membrane
2000x
decrease
Internal fouling
Membrane
Feed flow
External fouling
Fouling: A Major Limitation in Liquid
Filtration Membranes
9
HO
HO
NH2
N
OHHO
N
OHHO
N
HO OH
Dopamine Polydopamine
HO
HO
NH2
N
OHHO
N
OHHO
N
HO OH
Dopamine Polydopamine
H. Lee, S.M. Dellatore, W.M. Miller, and P.B. Messersmith., Mussel-Inspired
Surface Chemistry for Multifunctional Coatings. Science, 318, 426-430 (2007).
Mimicking Mussel Adhesion (“Bio-Glue”)
10
Polydopamine
Polydopamine: Novel Fouling Resistant
Membrane Coating
11
Michael Addition/ Schiff Base Reaction O
CH3H2Nn
Polydopamine
PEG ad-layer
Proposed Polydopamine Structure:
N
O
O
H
N
HN
O
H
PEG
Polydopamine as Surface “Primer” to Graft
PEG to Membrane Surfaces
12
80
100
120
140
160
0 0.2 0.4 0.6 0.8 1
Flu
x [
Lm
-2h
-1]
Time [h]
Unmodified (85.4% rejection)
PTFE MFPDOPA-g-PEG modified
(94.5% rejection)
PDOPA modified
(95.7% rejection)
Conditions: P=0.3 atm, crossflow=120 L/h (Re=2500) 1500 ppm soybean oil/DC193-water emulsion (non-ionic)
Modification: 60 min PDOPA deposition time followed by 60 min 5KDa PEG-NH2 (1mg/mL, 60 °C)
Oily Water Filtration Using Pegylated Polydopamine
Treated Teflon Microfiltration Membranes
13
- 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
Field Validation - Visual
14
- 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
Unmodified
Modified
40% Lower Energy
2X More Water
Processed Between
Cleanings
Field Validataion: Ultrafiltration of Bioreactor
Effluent
15
• 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 with membranes: An overview, Industrial & Engineering Chemistry Research. 47 (2008) 2109-2121.
Natural Gas Processing
Science, vol. 318, 12 October 2007, pp. 254-258.
17
CO2/CH4 Separation Performance
1: PIOFG-1 2: TR-1-350 3: TR-1-400 4: TR-1-450 5-19: OTHER TR POLYMERS
N NCF3
CF3
O
OO
OOH OH
F3C CF
3
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
Transport of Small Molecules and Ions, Science, 318, 254-258 (2007).
18
2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
(d)
(c)
(b)
R
ela
tive in
ten
sit
y (
a.u
.)
Cavity radius (A)
(a)
o
Cavity Size Distribution from Positron
Annihilation Lifetime Spectroscopy
(a) PIOFG-1
(b) TR-1-350
(c) TR-1-400
(d) TR-1-450
N NCF3
CF3
O
OO
OOH OH
F3C CF
3
Lin et al., Science, 311, pp. 639-642 (2006).
Beating the Permeability-Selectivity Tradeoff
for H2 Purification
20
Reduction to Practice
CO2 Selective Materials
Using Nanocomposites to Enhance Membrane Separations
Using Nanolayering to Enhance Gas Barrier Properties