Fabrication of high performance nanofiltration membranes based on the interfacial polymerization regulated by the incorporation of dextran nanoparticles

Abstract

The thin-film composite (TFC) nanofiltration (NF) membrane is an excellent choice to solve water shortage based on the advantages of high flux and selective separation. However, the current NF membrane still causes a tremendous amount of energy consumption in the practical applications due to the limitation of flux. In this work, dextran nanoparticles (DNPs) with the cross-linked organic components, numerous hydrophilic groups and internal cavities were added into the aqueous phase solution, and novel NF membranes were fabricated by adjusting the concentration and particle size of DNPs to control the interfacial polymerization (IP) reaction. After modification, the decrease of membrane thickness and the increase of surface hydrophilicity improved the separation performance of NF membrane. The water flux of NF membrane with 0.5 wt% DNPs doping was up to 211.2 Lm−2h−1MPa−1, which was more than twice as high as the unmodified membrane with Na2SO4 retention up to above 98%. It was also worth mentioning that the modified membrane indicated excellent monovalent/divalent ion selectivity and anti-fouling performance. This strategy of improving membrane performance by controlling the concentration and particle size of the aqueous phase additives with the advantages of simplicity and universality provides a certain impetus for the development of TFC membrane.