Graphene oxide/multi‐walled carbon nanotubes nanocompsite polyamide nanofiltration membrane for dyeing‐printing wastewater treatment.

Graphene oxide (GO)/multi‐walled carbon nanotubes (MWCNTs) modified nanofiltration (NF) membranes were successfully fabricated by interfacial polymerization of piperazine (PIP) and 1,3,5‐benzenetricarbonyl trichloride (TMC). Compared with the pristine polyamide (PA) membrane and GO membrane, the typical structure of the granular protrusions on the surface of the GO/MWCNTs membrane gradually disappeared, and a regular ordered morphology appeared. The membrane thickness and surface roughness were increased according to the results of field emission scanning electron microscopy (FE‐SEM) and atomic force microscopy (AFM). The contact angle of GO/MWCNTs NF membranes progressively decreased from 57° to 23°, indicating the enhancement of surface hydrophilicity. The best NF performance was achieved when the ratio of GO to MWCNTs was 6:3 (G‐M‐3). The water flux was 55.6 L/m2.h, which was 33.7% higher than that of the GO membrane, and the rejection rate for Na2SO4 was maintained at approximately 94%. Both modified NF membranes could treat actual dyeing‐printing wastewater effectively. The anti‐fouling performance of G‐M‐3 was better than that of G3. Therefore, GO/MWCNTs‐modified NF membranes have a good application prospects in the field of wastewater treatment and water purification. [ABSTRACT FROM AUTHOR]