Treating sulfur black dye wastewater with quaternized poly (phthalazinone ether sulfone ketone) nanofiltration membranes

Two kinds of nanofiltration (NF) membranes were investigated in treating the Sulfur Black B dye wastewater. Negatively charged polypiperazine amide/poly (phthalazinone ether sulfone ketone) (PIP/PPESK) NF membrane was prepared by interfacial polymerization method while positively charged quaternized poly (phthalazinone ether sulfone ketone) (QAPPESK) membrane was prepared by phase inversion method. QAPPESK NF membrane was selected for further study because it performed higher dye rejection and flux compared with the PIP/PPESK NF membrane. The effects of different operation conditions were systematically studied based on the rejection and desalination of the dye. Over 14.5 L/m(2)h flux, 92.3 % dye rejection and 10 % salts rejection were observed in the long term operation at 60 degrees C which indicated that the QAPPESK membranes could be successfully applied in the sulfur black dye wastewater treatment and inorganic salts reuse.