Researchers at the University of Alabama tested PVDF ultrafiltration membranes modified with different amine groups for removing DBSA, a common anionic surfactant that resists conventional water treatment. The study, published in Frontiers in Membrane Science and Technology, compared primary, secondary, tertiary, and quaternary amine variants at a high DBSA concentration of about 600 mg/L. The tertiary amine membrane performed best, removing 95.3 percent of DBSA in three hours, while the quaternary version was slower but more stable across repeated use. The work shows that amine structure matters for both speed and reversibility. Modified membranes reached adsorption capacities up to 22.2 mg/g, and all variants kept around 70 percent removal after five regeneration cycles. The authors note that dynamic flow conditions still limit performance, so future work will need to increase surface amine density, for example with a thin polymer interlayer, before this approach is ready for real treatment plants.
