(450g) Magnetically Responsive Self-Cleaning Micro-Mixing Nanofiltration Membranes

Song, G., University of Arkansas
Qian, X., University of Arkansas
Wickramasinghe, S. R., University of Arkansas

Nanofiltration (NF) is a relatively new membrane separation technology mainly used for removing low molecular weight species from water. NF membranes suffer from concentration polarization thus aggravating membrane fouling and compromising the performance of membrane quickly. Magnetically responsive nanofiltration (NF) membranes with superparamagnetic nanoparticles attached to the chain ends of the grafted polymer nanolayers have been shown to be effective in breaking concentration polarization at the membrane-liquid interface under an appropriate external oscillating magnetic field. NF270 is one of the most commonly used NF membranes for removing low molecular weight species and divalent salt ions from the feed solutions. The effects of polymer grafting degree varying both the chain length and chain density were studied. In addition, the micro-mixing effects of magnetically activated membranes on flux and rejection for various concentrations of NaCl, CaCl2, MgCl2, MgSO4, Na3PO4 solutions as well as for feed solutions containing non-charged glucose and sucrose molecules. The magnetic field effect becomes more evident with increasing grafting degree as well as at high feeding concentration or for higher charged species after long period of operation. Moreover, our results also shed significant light on the effects of magnetic field on ion hydration and water structure.