Xinying Wang, Department of Chemical And Biological Engineering, Colorado State University, Fort Collins, CO 80523-1370, Xianghong Qian, Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1374, Scott Husson, Clemson University, 126 Earle Hall, Clemson, SC 29634, and Ranil Wickramasinghe, Colorado State University, Department of Chemical Engineering, Fort Collins, CO 80523-1370.
Water treatment is drawing increasing attention worldwide since water is a highly valuable natural resource. Pressure driven membrane separation processes provide many advantages for water treatment. Membrane fouling is a major concern. In this research program, we will modify commercially available nano-filtration membranes by growing polymer brushes from the membrane surface and then attaching super-paramagnetic nano-particles to the brush ends resulting in magnetically responsive, anti-fouling membranes for water treatment.
We have grafted polyacrylic acid (PAA) brushes to the surface of composite polyamide nanofiltration membranes (NF 270) and attached amine group coated super-paramagnetic particles (SPMPs) to PAA brush ends. Membrane surfaces were characterized by field emission scanning electron microscopy (FESEM), Atomic Force Microscope (AFM) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The results confirm our success at grafting PAA brush and attaching SPMPs. Attachment of SPMPs is also shown using a vibrating sample magnetometer (VSM) which indicates that there is no hysteresis in the magnetization curve as expected for SPMPs. Some preliminary oily water separation data were obtained using our modified membrane under an alternating magnetic field. The results indicate that movement of the magnetically active brushes suppresses fouling.