Enriching Fe3O4@MoS2 composites in surface layer to fabricate polyethersulfone (PES) composite membrane: The improved performance and mechanisms

Transition metal dichalcogenides (TMDs) have been regarded as prominent nanofiller to manufacture high-performance mixed-matrix membranes. However, their efficient application still faces the challenge of reasonable nanostructure regulation and controllable distribution of TMDs nanofillers. In this work, magnetic Fe3O4@MoS2 composites with hierarchical flower-like structure were firstly synthesized and then mixed in polyethersulfone (PES) casting solution. A composite membrane was fabricated by enriching Fe3O4@MoS2 in the membrane's upper layer with the assistance of a magnetic field. The Fe3O4@MoS2 composites endowed the composite membrane with enhanced permeability, rejection and self-cleaning performance for filtration of typical foulant (bovine serum albumin (BSA) and humic acid (HA)) solutions. The optimum membrane possessed a pure water flux of 550.7 +/- 22.7 L.m(-2).h(-1).bar(-1), which is about 1.85 times higher than that of the bare PES membrane. Meanwhile, the modified membrane had a rejection to BSA and HA higher than 90 % as compared with only about 60 % for the bare membrane. Furthermore, the cyclic filtrations revealed that the membrane flux can be recovered 90 % under visible light irradiation, indicating the excellent photocatalytic self-cleaning ability introduced by Fe3O4@MoS2. Mechanisms underlying the improved antifouling performance and self-cleaning ability of the composite membrane were proposed. The facile strategy, together with the improved membrane performance clearly demonstrates broad application prospect of the Fe3O4@MoS2 PES composite membrane in water treatment.