Composite NF membranes with anti-bacterial activity prepared by electrostatic self-assembly for dye recycle

Composite nanofiltration (NF) membranes with anti-bacterial activity were prepared by electrostatic self-assembly. A novel composite (Ag+-PEI/ Cu2+-PEI/ Fe3+-PEI) was obtained by the chelate reaction of polyethylenimine (PEI) with metal ion, which constituted the main component of the separation layer of the prepared membrane. Three composite (Ag+-PEI/ Cu2+-PEI/ Fe3+-PEI) NF membranes prepared at optimized condition exhibited excellent permeability (121 L.m(-2).h(-1).MPa-1/71 L.m(-2).h(-1).MPa-1/ 73 L.m(-2).h(-1).MPa-1) and high rejection (96.5%/ 94.5%/ 91.6%) for acid fuchsin as well as low rejection (31.5%/ 27.5%/ 23.7%) for MgSO4. Meanwhile, the higher flux recovery ratio (FRR) of dye was observed for the Fe3+-PEI membrane (FRRFe=91.5%) than that for others ((FRRCu=83.2%) and (FRRAg=76.4%)). Furthermore, these three NF membranes also presented good hydrophilicity (59 degrees/39 degrees/35 degrees), excellent anti-bacterial activity (up to 95% against E. coil and over 90% against S. aureus) and good long-term stability in our trails. These results were of great significance for dye recycle in industrial field. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.