High-performance and robust polysulfone nanocomposite membrane containing 2D functionalized MXene nanosheets for the nanofiltration of salt and dye solutions

Polysulfone (PSF) is widely applied in the fabrication of nanofiltration membranes. However, its low hydrophilicity is a major problem that lowers the permeate flux and intensifies membrane fouling. MXene, as a promising nanomaterial in the hydrophilicity improvement of polymeric membranes, has not been incorporated into the PSF nanofiltration membranes yet. In the current research, hydrophilic MXene nanosheets were synthesized using Ti3AlC2 as the precursor. Energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction spectroscopy (XRD), transmission electron microscopy, and scanning electron microscopy (SEM) were applied to assess the functionalization of MXene with the OH functional group and its layered structure, respectively. Then, PSF/MXene nanofiltration membranes were prepared for the first time. The membranes were characterized, and their performance was compared in the filtration of salt and dye solutions and a model foulant. Incorporating MXene nanosheets into the PSF matrix boosted the membrane porosity, hydrophilicity, and tensile properties. With loading 1 to 4 wt% MXene into the PSF membrane, nanofiltration membranes with rejection values higher than 90% for MgSO4, MgCl2, and methyl orange were obtained. PWF of the membrane loaded with 4 wt% MXene was almost four times as high as the neat PSF membrane, and its flux recovery was approximately 73% higher.