Nanofiltration membrane cross-linked by m-phenylenediamine for dye removal from textile wastewater

In this work, m-phenylenediamine (MPD) is used to prepare cross-linked polyetherimide (PEI)-based nanofiltration (NF) membrane for treatment of dye containing wastewater. The effects of dope solution composition, cross-linking time, and dye concentration on membrane performance are investigated. Results indicate that the rejection of dye is increased with the increase of acetone concentration in the dope solution, cross-linking time, and dye concentration. Meanwhile, membrane flux showed the opposite trend. With the aid of SEM and FTIR analysis, the cross-linking between MPD and PEI is confirmed. The cross-linked membrane has thicker and dense selective layer compared to the unmodified membrane. The cross-linked NF membrane (PEI: 15 wt%; acetone: 20 wt%; cross-linking time: 10 minutes) showed good performance in filtration of synthetic dye wastewater (Reactive Red 120, 1500 ppm) with 98% dye rejection and 0.013 L m(-2) hour(-1) of flux at relatively low operating pressure (60 psi).