High performance nanofiltration membrane based on SMA-PEI cross-linked coating for dye/salt separation

Abstract Construction of high performance nanofiltration (NF) membrane is of critical importance in dye desalination. In this paper, a novel composite NF membrane with good dye/salt separation performance was prepared via blending and crosslinking method. Firstly, the membrane matrix was prepared by blending styrene-maleic anhydride (SMA) with polyether sulfone (PES) via non-solvent induced phase separation (NIPS), then polyethylenimine (PEI) was introduced on the membrane surface by crosslinking reaction with SMA. Single component filtration tests of the prepared NF membrane showed that the rejection of the dye with the molecular weight greater than 696 Da reached more than 99% and the membrane possessed high flux of above 23 L/m2 h bar. The separation tests of Congo red and NaCl mixed solution at optimized conditions exhibited 99.4% rejection for Congo, and 2.5% rejection for NaCl, moreover, the separation performance remained stable in the test run for 36 h. All these indicate that the prepared NF membrane can be applied to dye desalination.