Impacts of Hydrophilic Membrane Additives on the Ultrafiltration of River Water

One of the most serious disadvantages of membrane applications in water treatment is the decreasing water permeation rate with time, which is often called fouling. This study investigates surface modification of polyethersulfone (PES) ultrafiltration membranes as a fouling reduction strategy for drinking water treatment applications. Surface modification was achieved through the addition of three different tailor-made hydrophilic surface modifying macromolecules (LSMM200, LSMM400, and LSMM600). Flat sheet membranes were prepared via a single-step casting procedure; their surface hydrophilicity was quantified via contact angle measurements. The incorporation of hydrophilic additives produced slightly more hydrophilic membranes (contact angle reduction of up to 8°) and improved membrane performance compared with the PES membrane without blending. In the treatment of highly colored river water, LSMM400- and LSMM600-modified membranes achieved up to 32% higher final fluxes. Surface modification resulted in significantly decreased flux reductions and natural organic matter accumulation. Dissolved organic carbon removals were approximately 70% for all the membranes studied. No clear correlation between membrane hydrophilicity and fouling reduction was observed.