281204 Effect of Mixed Monovalent and Divalent Ion Feeds On Sulfonated Polysulfone Desalination Membrane Performance

Wednesday, October 31, 2012: 2:10 PM
403 (Convention Center )
Joseph R. Cook1, Geoffrey M. Geise2, Habis Al-Zoubi3, Benny D. Freeman4, Kwansoo Lee5, Benjamin Sundell6 and James E. McGrath6, (1)Chemical Engineering, The University of Texas at Austin, Austin, TX, (2)Deptartment of Chemical Engineering & The Texas Materials Institute, The University of Texas at Austin, Austin, TX, (3)Al-Hussein Bin Talal University , Ma'an, Jordan, (4)Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, (5)Virginia Tech, (6)Chemistry, Virginia Tech, Blacksburg, VA

Modern water desalination membranes are largely based on crosslinked polyamides chemistry, which are susceptible to degradation by exposure to chlorine compounds, which are often necessary to act as a biocide to prevent fouling of the membranes. Sulfonated polysulfones show promising water/salt separation properties and significant resistance to degradation by chlorine compounds.  These materials consist of randomly copolymerized charged and uncharged monomers, and these charge groups directly affect the salt and water transport and separation performance. One challenge of these materials is that they show reduced sodium chloride rejection when even relatively low amounts of divalent salts (such as calcium chloride or magnesium chloride) are added to the feed.  This work investigates the effect of the chemistry and concentration of salts in the feed on different transport properties: water and salt permeability, water and salt partition coefficients, and water diffusivity. These properties are determined first in a feed of sodium chloride in water, with the competing ion added in increasing amounts to quantify the effect of competing ion concentration on performance.  Tests are also performed with increasing amounts of sodium chloride, and different monovalent competing ions (such as potassium chloride) are investigated to demonstrate the prevalence of the phenomenon with divalent ions.

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See more of this Session: Membranes for Water Treatment II
See more of this Group/Topical: Separations Division