NAMS 2002 Workshop - ICOM 2008

Nanofiltration and Reverse Osmosis I - Membranes – 2
Monday July 14, 3:00 PM-3:30 PM, Maui
Desalination Membranes Based on Directly Sulfonated Poly(arylene ether
sulfone) Copolymers
H. Park (Speaker), University of Ulsan, Ulsan, Korea, hbpark@ulsan.ac.kr
W. Xie, University of Texas at Austin, Austin, TX, USA
B. Freeman, University of Texas at Austin, Austin, TX, USA
M. Paul, Macromolecules and Interfaces Institute and Department of Chemistry, Blacksburg, VA,
USA
H. Lee, Macromolecules and Interfaces Institute and Department of Chemistry, Blacksburg, VA,
USA
J. Riffle, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
J. McGrath, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
We have synthesized and characterized a systematic series of new sulfonated
copolymer membranes, for use as desalination membranes, based on chemistry
that is entirely different from the conventional post-polymerization sulfonation
technique. Using direct copolymerization of sulfonated and other monomers,
reproducible sulfonated copolymer membranes can be prepared as various
polymer structures and compositions at different levels of sulfonation. This
synthesis method overcomes the problems of conventional sulfonation
technology such as molecular weight reduction during sulfonation. This study will
discuss the preparation and evaluation of several families of sulfonated polymers
such as random or segmented multiblock copolymers in terms of desalination
characteristics (e.g., water permeability (or permeance), salt permeability and
salt rejection). These sulfonated polymers or their thin-film composite
membranes exhibit high tolerance to chlorine attack, which is in contrast to
conventional desalination membranes such as those based on aromatic
polyamides or cellulose acetate. They also exhibit high water flux and good salt
rejection. To delineate structure-property relations for these materials, solubility
and diffusivity of water and various salts were also evaluated for a series of
sulfonated polymers. These intrinsic properties were compared with those of
commonly used cellulose acetate and polyamide membranes. This fundamental
and systematic study of structure-property relations regarding newly synthesized
sulfonated copolymer membranes provides guidelines regarding material
selection for new reverse osmosis membranes.