Polyelectrolyte electrostatically self-assembled modified porous polyacrylonitrile nanofibers as adsorbents for anionic dye removal

Herein, we chose PAN with good sunlight and weather resistance and easy surface modification as the electrospinning material to prepare the PAN nanofiber membrane. Then the surface modification of the obtained PAN fiber membrane was carried out sequentially by alkali hydrolysis and acid neutralization to make the surface of the fiber membrane negatively charged. Finally, the positively charged polyelectrolyte PAH on the surface was selected as the functional material, and a simple and environmentally friendly electrostatic selfassembly method was adopted to modify the prepared PAN nanofiber membranes labeled as PAN@PAH. This treatment effectively increased the storage space and adsorption groups of the fiber membranes, which led to a significant increase in the removal ability of anionic dyes in wastewater. In particular, the PAN@PAH nanofiber membrane adsorbed 439.66 mg/g of methyl orange and 946.83 mg/g of Congo red, which showed better adsorption capacity than many other membranes reported in the literature. Moreover, the adsorption capacity of PAN@PAH remained at 90.19 % after eight adsorption-desorption cycles. The preparation method and modification strategy of this membrane adsorbent provides new ideas and methods for the removal of other anionic dyes.