Electrospinning fabrication of flexible Fe3O4 fibers by sol-gel method with high saturation magnetization for heavy metal adsorption

Magnetic fibers adsorbent has attracted more and more attention because of the large surface area and overcoming the disadvantages of easy agglomeration and difficult separation. Adding Fe3O4 nanoparticles into spinning solution followed by electrospinning is a common method to prepare magnetic fibers. In this paper, a new sol-gel method was developed to prepare Fe3O4 fibers, which overcame the disadvantage of low saturation magnetization due to the limited amount of magnetic nanoparticles in spinning solution, and uneven distribution of magnetic nanoparticles in the fibers. Through studying the effect of the proportion of ethanol in the solvent and the amount of solvent on the surface tension, the conductivity and viscosity of the spinning solution, and the spinning solution with the best spinnability were explored. The prepared Fe3O4 fibers had high saturation magnetization and maintained excellent flexibility. They had the advantages of self-supporting without agglomeration, and were easier to magnetically separate than Fe3O4 powder prepared by the same method. In addition, the adsorption and regeneration performances for Pb(II) of Fe3O4 fibers were better than those of Fe3O4 powder. Fe3O4 fibers were suitable for heavy metal adsorbent or adsorbent core, which became another effective strategy to expand the application prospects of magnetic adsorbents.