water purification with new chlorine- and fouling-resistant reverse osmosis and nanofiltration...
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Water Purification with New Chlorine- and Fouling-Resistant Reverse Osmosis and Nanofiltration Membranes: An alliance of Virginia Tech, the University of Texas, Hydrosize and Dow Filmtec
James E. McGrath, Virginia Tech, DMR 0650277
Technical Merit: This Partnership for Innovation Program has developed durable anti-fouling chlorinated disinfectant resistant reverse osmosis and nanofiltration membranes for water purification. The collaboration between VT and UT has critically combined novel copolymer synthesis and molecular characterization with membrane studies. The partners particularly contributing to the research have been Dow FilmTec and a small start-up company, Hydrosize, Inc. The important improvement in chlorine resistance is shown below in Figure 1. We have also developed an effective processing technique to produce a thin skin-foamed core asymmetric membrane, which is shown in Figure 2. The developments greatly simplify the desalination process to two steps, which will involve chlorination to control algae, followed by desalination to produce water. The process is expected to extend product lifetime, simplify maintenance and operation, and to provide cost savings by eliminating one extra step of chlorination-dechlorination, which is required by current membranes.
40
50
60
70
80
90
100
0 4000 8000 12000 16000
NaC
l rej
ecti
on (
%)
Chlorine exposure (ppm-hours)
SW30HR(FilmTec)
BPS40H
BPS40N
O
S
O
O
O O S
O
O O
SO3-M+
-O3S
x 1-x
+M
BPS40H (x = 0.4 and M = H (acid form) and BPS40N (x = 0.4 and M
= Na, (sodium salt form))
40
50
60
70
80
90
100
0 4000 8000 12000 16000
NaC
l rej
ecti
on (
%)
Chlorine exposure (ppm-hours)
SW30HR(FilmTec)
BPS40H
BPS40N
O
S
O
O
O O S
O
O O
SO3-M+
-O3S
x 1-x
+M
BPS40H (x = 0.4 and M = H (acid form) and BPS40N (x = 0.4 and M
= Na, (sodium salt form))
Effect of chlorine exposure on NaCl rejection of VT disulfonated copolymers relative to a commercial PA membrane (SW30HR, Filmtec) in the presence of free chlorine (as hypochlorite). Feed concentration = 2,000 ppm NaCl, Feed pressure = 400 psig
VT-UT Membranes are Stable to Disinfectants!
Phase inversion asymmetric membranes from BPS20
Water Purification with New Chlorine- and Fouling-Resistant Reverse Osmosis and Nanofiltration Membranes: An alliance of Virginia Tech, the University of
Texas, Hydrosize and Dow Filmtec James E. McGrath, Virginia Tech, DMR 0650277
Impact on Society: Support from this PFI has enabled us to create and implement an innovation-enabling process, whereby both small and large commercial partners can collaborate to exploit research on RO and NF membranes by the university partners. We have prepared students and post-doctoral associates for employment where teamwork, sound business principles, and communication skills complement a sound technical foundation. This research will also facilitate the market entry of RO and NF systems using the Partnership infrastructure.
The research has been presented at several international technical conferences and published in two peer reviewed journals (Polymer and Angewandte Chemie International Edition). The latter has attracted a great deal of attention, and even merited a press release. Dow Filmtec has started a 2-year, $550,000 program jointly with VT and UT in July 2008. We are developing relationships and have proposals into Solvay, Statkraft (Norway) and the DOE (National Energy Technology Laboratory, NETL).
The research over the past year has been largely conducted by Dr. Mou Paul (left), who worked with Prof. Riffle at VT, and who recently received her PH.D. in Macromolecular Science and Engineering at VT; Dr. Ho-Bum Park (right), who worked with Prof. Freeman at UT, and who has now been awarded a position as a professor at Ulsan University in Korea; and Ms. Natalie Arnett (center), who works with Prof. McGrath. She is currently writing her Ph.D. thesis and expects to graduate within the year.