Novel Nonporous Fouling-Resistant Composite Nanofiltration Membranes by uoy21072


									                               Novel Nonporous Fouling-Resistant                                                Compliance
                                   Composite Nanofiltration
Background:                                                        shipboard wastewater treatment facility to enable the Navy
The principal problem inhibiting widespread adoption of            to meet current and anticipated wastewater purification
nanofiltration/ultrafiltration to treat shipboard wastewater       targets. This technology is widely applicable to Navy and
and allow the Navy to meet future overboard discharge              civilian ships and to onshore treatment of waste waters.
limits is fouling associated with available membranes.
Existing nanofiltration/ultrafiltration membranes are finely
porous and are subject to surface or internal fouling by
particulates, resulting in a dramatic decline in the water flux.

This project developed a shipboard wastewater treatment
system based on a novel type of fouling-resistant,
composite-membrane module. The composite membrane
consisted of an ultrathin (0.2-0.5 micrometer), nonporous,
highly water-permeable, rubbery, block copolymer layer
coated onto a conventional, microporous ultrafiltration or
nanofiltration membrane for support. This coating layer
provides fouling resistance without significantly reducing
the water flux.

Summary of Process/Technology:
Three candidate materials were developed under earlier                              Coating Materials Design
Office of Naval Research grants. In this project,
development of these membranes was completed and a
systematic series of new materials was synthesized and             Accomplishments:
characterized. The properties of these new heterophase block       Model compound studies were completed, and polymer
copolymer membrane materials were tailored to provide              precursors were prepared. The first generation of
better fouling resistance than conventional membranes,             poly(ethylene oxide)-b-poly(p-benzamide) was synthesized
while maintaining or improving the flux/selectivity                and two polymer samples were identified. Films for
combinations relative to currently available materials. These      characterization were also prepared. The performance and
materials were based on aromatic polyamide hard blocks             stability of a module containing Pebax 1074 membrane
with either hydrophilic ether groups as the soft, water-           coated onto a microporous poly(vinylidene fluoride) support
permeable block or water-soluble aromatic polyamides as            was determined to be an effective solution to oil/water
the hydrophilic blocks. This research characterized the            emulsion fouling. Various samples demonstrated the porous
physical, chemical, and morphological structure of these           membrane water production rate to be more than ten times
materials as well as their water permeation, rejection, and        lower than that of a coated membrane. This project was
fouling properties. Systematic structure/property relations        completed in FY 2000.
were developed to guide the preparation of a new generation
of advanced high performance materials for shipboard               Contact Information:
wastewater treatment. The best performing membrane                 Dr. Benny Freeman
materials were selected for Coating Materials Design scale-        University of Texas at Austin
up to bench-scale and then to industrial-scale membrane            Center for Energy and Environmental Resources
modules for evaluation in a pilot-scale system.                    10100 Burnet Road, Building 133
                                                                   Austin, TX 78758
Benefit:                                                           Phone: (512) 232-2803
Novel, low-fouling membranes for graywater and bilgewater          Fax: (512) 232-2807
treatment offer longer service life and less frequent cleaning.    E-mail:
When housed in high performance modules, these
membranes provide a compact, reliable, economical        

                                                                                                                  REVISED 11/07/02

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