Functionalized polyvinyl alcohol/polyethylenimine magnetic iron oxide electrospun fibers as effective chromium (VI) adsorbent for water solution

Composite electrospun fibers have been extensively investigated as adsorbents for the waste water treatment. In this study, branched polyethylenimine (b-PEI)/polyvinyl alcohol (PVA) composite electrospun fiber adsorbent was fabricated and followed by cross-linking to render the fibers with good water stability, meanwhile Fe3O4 particles were also immobilized on the fiber surface. The formation of PVA/PEI magnetic nanofibers were characterized via different techniques, with the aim of using them for efficient Cr(VI) removal from aqueous solutions. Various factors,such as solution pH, initial Cr(VI) concentration, contact time and coexisting anions, were analyzed during the adsorption process. The results showed that the Cr(VI) adsorption was highly pH dependent, and the maximum adsorption capacity reached up to 526.4 mg/g at 298 K. Experimental data, obtained from adsorption kinetics and adsorption isotherms studies, could be well fitted by Langmuir adsorption isotherm and first-order model. The desorption efficiencies of Cr(VI)-loaded on PVA/PEI magnetic nanofibers were evaluated using 0.5 mol L−1 NaOH, The adsorption–desorption process is conducted for 5 cycles and the removal efficiency still keeps 96% after 3 cycles.