Highly compressible composite aerogels constructed by coaxial electrospun fibres and graphene for water sterilization

The electrospun fibres/graphene composite aerogels were assembled with the addition of amino trimethylene phosphonic acid (ATMP). Coaxial electrospinning was employed to attach nanosized-zinc pyrithione, a broad-spectrum biocide, on polyacrylonitrile (PAN) fibre surfaces. Reaction between ATMP and graphene oxide promoted the crosslinking structure of graphene-based aerogels, while producing antibacterial quaternary ammonium and attaching phosphonic acid groups to chelate the metal ions. The addition of the electrospun fibres in the composite aerogels improved the compressive stress at 50% strain by 540% upon the heat treatment at 200 °C, while the sterilization ratio of E. coli reached 100%. The heat treatment was critical for the mechanical properties of the composite aerogels because the linear chains of PAN were turned into rigid ladder polymer upon cyclization, while covalent interaction was introduced between residual carboxyl groups on graphene layers and CN groups of cyclized PAN. The electrospun fibres/graphene composite aerogels can be effectively applied to remove pathogenic bacteria, organic dyes and heavy metal ions in polluted water.