Mixed matrix polyethersulfone tight ultrafiltration (TUF) membrane with improved dye removal by physical blending of 2D MoS2

Tight ultrafiltration (TUF) membrane as a kind of ultrafiltration membrane has great promising applications in wastewater treatment and molecule separation. We report a facile and scalable technique for the fabrication of mixed matrix TUF membrane by physical blending of two-dimensional (2D) molybdenum disulfide (MoS 2 ) with polyethersulfone dope solution. The incorporated MoS 2 sheets affected the phase inversion process and changed the membrane structure. Morphology, molecular weight cut-off, hydrophilicity, and mechanical strength properties of the prepared membranes were investigated. The characterization by field emission scanning electron microscopy confirmed that MoS 2 sheets were successfully embedded in the membranes and transmission electron microscopy confirmed the well-distribution of MoS 2 in the membrane matrix. Results demonstrated that the pore size of membranes was effectively tailored by varying the content of MoS 2 from 0 to 5.0 wt.% in casting solutions. The modified TUF membranes with MoS 2 concentration in the range of 2.5–4.0 wt.% showed an enhanced pure water flux and higher polyethylene glycol (PEG, 10 kDa) rejection compared to the pristine membrane. An optimized pure water flux of 84.7 L m –2 h –1 bar –1 and a superior PEG 10 kDa rejection of 95.2% were obtained for the membrane modified by MoS 2 sheets with a concentration of 3.0 wt.%. Moreover, the as-prepared TUF membrane showed 91.6% rejection rate for a small molecule (rose bengal, 1,017 g mol –1 ), indicating their narrow pore size. This work has highlighted the facile physical blending of MoS 2 and polymeric dope solution, thus providing a promising application for other polymeric ultrafiltration membranes.