Polydopamine assisting the continuous growth of zeolitic imidazolate framework-8 on electrospun polyacrylonitrile fibers as efficient adsorbent for improved removal of Cr(VI)

Abstract Polydopamine‑functionalized polyacrylonitrile (PAN) fibers and integration zeolitic imidazolate framework-8 (ZIF-8) into electrospun fibers both have been proved the greater potential in removal Cr(VI) ions from aqueous solution, based on our previous works. Here, an efficiency adsorbent was facilely fabricated by polydipamine (PDA) coating assisting ZIF-8 growth on the electrospun PAN fibers. Benefiting from abundant functional groups (including amino and hydroxyl) of PDA coating, the ZIF-8 nanoparticles rapidly and effectively grew on the fiber surface, and thicker ZIF-8 layer was obtained by prolonging the reaction time. The obtained composite ZIF-8@PDA/PAN fibers retained high surface area (299.9 m2·g− 1) and pore size, and exhibited super-hydrophilicity and high water-stability, which were vital for the Cr(VI) removal. The composite fiber exhibited significant removal efficiency (more than 90% at lower initial Cr(VI) concentrations), good adsorption capacity (212.7 mg·g− 1) and excellent recyclability.