AWWA MTC61238

This study modified commercially-available cellulose acetate ultrafiltration membranes using a novel graft polymerization technique. In the technique, membrane surface radicals were formed by inserting the membrane in an oxidant solution for dehydrogenation of end functional groups, the membrane was graft polymerized, and in order to control grafted chain length and density, the membrane was placed in a solution containing a chain transfer agent. Modification led to no significant differences in membrane roughness with the virgin and modified membranes displaying roughness values of 4.784 and 4.237 nm, respectively. After fouling, the virgin membrane roughness had increased to 23.002 nm, while that of the modified membrane to 12.613 nm; that is, a significant decrease in membrane roughness induced by fouling due to the modification. Further, in comparing membrane permeability between the virgin and modified membranes, it was determined that modification did not affect membrane permeability. Finally and consistently throughout the study, the selectivity of the modified membrane was on average 15% higher than the selectivity of the virgin membrane when the same feed water was filtered through both. Includes 30 references, figures.