Towards improved antifouling ability and separation performance of polyethersulfone ultrafiltration membranes through poly(ethylenimine) grafting

Poloxamer 407 Combined with Polyvinylpyrrolidone To Prepare a High-Performance Poly(ether sulfone) Ultrafiltration Membrane

At present, the design and fabrication of polymer membranes with high permeability and good retention ability are still huge challenges. In this study, the commercial Poloxamer 407 (Pluronic F127) is selected as a multifunctional additive, and polyvinylpyrrolidone is used as a pore-forming agent to modify the poly(ether sulfone) membrane by liquid-liquid phase conversion technology to prepare an ultrafiltration membrane with excellent performance. The hydrophobic poly(propylene oxide) segment in Poloxamer 407 guarantees that this copolymer can be firmly anchored to the poly(ether sulfone) matrix, and the hydrophilic poly(ethylene oxide) segments in Poloxamer 407 impart a stronger hydrophilic nature to the modified membrane surface. Therefore, the permeability and hydrophilicity of the modified membrane are significantly improved and the modified membrane also has good stability. When the amount of Poloxamer 407 added to the casting solution reached 0.6 g, the water flux of the modified membrane was as high as 368 L m-2 h-1, and the rejection rate of bovine serum albumin was close to 98%. In the test to isolate organic small molecule dyes, the retention rate of the modified membrane to Congo red is 94.27%. In addition, the modified membrane shows an excellent water flux recovery rate and antifouling ability. It performs well in subsequent cycle tests and long-term membrane life tests and can be used repeatedly. Our work has resulted in poly(ether sulfone) membranes with good performance, which show great potential in the treatment of biomedical wastewater and the removal of industrial organic dye wastewater, it provides ideas for the development and application of amphiphilic polymer materials.

Viscous Solvent-Assisted Planetary Ball Milling for the Scalable Production of Large Ultrathin Two-Dimensional Materials

Ball milling is a widely used method to produce graphene and other two-dimensional (2D) materials for both industry and research. Conventional ball milling generates strong impact forces, producing small and thick nanosheets that limit their applications. In this study, a viscous solvent-assisted planetary ball milling method has been developed to produce large thin 2D nanosheets. The viscous solvent simultaneously increases the exfoliation energy (E_e) and lowers the impact energy (E_i). Simulations show a giant ratio of η = E_e/E_i, for the viscous solvent, 2 orders of magnitude larger than that of water. The method provides both a high exfoliation yield of 74%, a high aspect ratio of the generated nanosheets of 571, and a high quality for a representative 2D material of boron nitride nanosheets (BNNSs). The large thin BNNSs can be assembled into high-performance functional films, such as separation membranes and thermally conductive flexible films with some performance parameters better than those 2D nanosheets produced by chemical exfoliation methods.