Three-dimensional hierarchically structured PAN@γ–AlOOH fiber films based on a fiber templated hydrothermal route and their recyclable strong Cr(vi)-removal performance

Abstract

A simple route is presented to fabricate a polymer (polyacrylonitrile, PAN)@γ –AlOOH composite fiber film, with a three-dimensional hierarchical micro/nanostructure, based on electrospun fiber templated hydrothermal strategy. The composite fibers are nest-like in morphology and consist of cross-linked γ–AlOOH nanoplates, with 20 nm–40 nm of thickness, standing nearly vertically on the PAN fibers. The formation of such composite fibers are attributed to the template-induced heterogeneous growth of γ–AlOOH on the PAN fibers in alkaline conditions. Further, such fibers can be converted into the tubular Al₂O₃ hollow fibers with the nearly unchanged morphology after calcination in air. Importantly, the as-prepared PAN@γ–AlOOH composite fibers have shown a much higher adsorption capacity than the normal γ–AlOOH nanopowders, and especially, exhibited very good recycling performance (more than 85% of its original adsorption capacity after 4 cycles), as an adsorbent to remove the heavy metal ions, Cr(VI), from model wastewater. This material could thus serve as an effective recyclable adsorbent with easy separation from solution. Also, it is expected to have other potential applications in the role of a sensitive material or catalyst.