AWWA MTC50233

A series of experimental sulfonated polyether-ethersulfone/polyethersulfone (SPEES/PES) ultrafiltration membranes, whose chemical compositions were systematically varied, were examined to determine net surface charge by quantifying the amount of uranyl cation (UC) binding. Membrane samples were exposed to a 0.01M aqueous solution of uranyl acetate (UA) for two hours followed by extensive rinsing in deionized water. Membrane bound radioactive UC was quantified using liquid scintillation counting. Results indicated that UC binding increased in direct proportion to the amount of SPEES/PES block copolymer added to the polymer mixture during synthesis (Pearson R2=0.96). Pretreatment of the membrane surface with dodecyltrimethylammonium bromide, a quaternary ammonium surfactant, resulted in a decrease in UC binding, consistent with the occurrence of ionic interactions between the sulfonate groups on the membrane surface and the uranyl species. Includes 11 references, table, figures.