A mussel-inspired hybrid copolymer adhered to chitosan-coated micro-sized carbon fiber aerogels for highly efficient nanoparticle scavenging

The extensive use of nanomaterials in commercial products will lead to environmental contamination, which may cause serious health issues in the future. To date, limited scavengers have been available for the capture of these emerging nanopollutants from water. The aim of this work was to synthesize hybrid ternary co-polymer membrane-coated micrometer-sized carbon fiber aerogels (MCFAs) to remove emerging nanopollutants from water and to investigate the mechanisms involved. The MCFAs were fabricated by direct pyrolysis of cotton in an inert atmosphere. Post-modification with chitosan (CS) and dopamine–polyethylenimine (PEI) complex generated amine-coated MCFAs with porous textures, followed by protonation using diluted acid solution. The surface functional groups and morphologies of the ternary CS and dopamine–PEI co-coated MCFAs were systematically characterized. The as-obtained hybrid composite was successfully used for the removal of citrate-capped gold and silver nanoparticles from water. The equilibrium data were well fitted to the Langmuir isotherm model, with maximal adsorption capacities of 31.2 mg g−1 (Au NPs) and 41.8 mg g−1 (Ag NPs) at ambient temperature. The highest adsorption capacities reached 30.2 mg g−1 (Au NPs) and 34.9 mg g−1 (Ag NPs) at the equilibrium concentrations; these were very close to the maximum adsorption capacities of the monolayers. In addition, the adsorption of both nanoparticles on the as-prepared composite followed the pseudo-second-order kinetics model. Therefore, this work may pave the way for enhancing the properties of MCFAs for removal of nanopollutants from medical and/or industrial wastewaters.