Ultralight and superelastic nanofiber aerogels with in-situ loaded polypyrrole for high-efficient Cr(VI) adsorption

Constructing 3-D nanomaterial-based adsorbents with good mechanical properties has attracted increasing attention. This paper reports a simple strategy to prepare ultralight and superelastic 3-D aerogels as efficient adsorbents for heavy metal Cr(VI) in wastewater by in-situ loading of polypyrrole on cellulose acetate nanofibers followed by freeze-drying method. By the way, the cellulose acetate nanofibers are prepared by electrospinning. The obtained aerogel shows obvious 3-D porous and cross-linked structure, in which polypyrrole is uniformly coated on the nanofiber surface. The aerogel shows good mechanical properties with high compressive strength of 14.49 kPa, and can be processed into any desired shape. Due to the advantages of large specific surface area and high porosity, the maximum adsorption capacity of Cr(VI) in wastewater can reach up to 244.65 mg/g. The adsorption process can be described by pseudo-second-order kinetic model and Langmuir isotherm adsorption model, and the reduction-adsorption mechanism of polypyrrole on Cr(VI) is also studied. The present work proposes a high-quality nanofiber aerogel for efficiently adsorbing Cr(VI), which may also hold good potentials in the field of assembled adsorption.