Self-cleaning micro/nano graded porous groove structure fiber membranes by coaxial spinning for purification of dye wastewater

Adjusting the structure of the membrane and improving its performance proved to be an effective technique for accomplishing efficient dye wastewater purification. Water erosion of polyvinylpyrrolidone (PVP) core in polyacrylonitrile (PAN) nanofiber membrane modified with UiO-66-NH₂ was successfully achieved, in this study, using coaxial electrospinning, and ZIF-8 with excellent performance was further epitaxy-grown in situ. Two differently shaped and positively charged MOFs confer strong adsorption capacity (adsorption capacity >2042 mg/g) on cationic dyes. In addition, the multi-dimensional separation pores brought by the micro/nano graded porous groove structure and MOFs not only make the membrane have excellent static adsorption performance, but also have excellent dynamic separation performance under the influence of toxic heavy ions (separation efficiency >99 %; Flux >1666 L m⁻² h⁻¹ bar⁻¹). More importantly, this special structure of the membrane has an excellent photocatalytic activity for the dye, so the membrane can be used for a long time in a green and environmentally friendly way. Together, membranes show a significant deal of potential for the treatment of wastewater containing dyes due to the combination of these outstanding characteristics.