A super biosorbent from dendrimer poly(amidoamine)-grafted cellulose nanofibril aerogels for effective removal of Cr(vi)

Abstract

Over the past decades, heavy metal ions, especially hexavalent chromium [Cr(VI)], have substantially ravaged the aquatic environment and human health. Thus, the development of new, more efficient, and environmentally friendly methods to tackle this problem becomes very urgent. In this study, a novel dendrimer poly(amidoamine)-grafted cellulose nanofibril (PAMAM-g-CNF) aerogel was synthesized for Cr(VI) removal. The morphology, structure and adsorption properties of the PAMAM-g-CNF aerogel were investigated in detail. The results indicated that the aerogel bore abundant functional groups with a bimodal pore structure and a high specific surface area, all of which are essential for an efficient adsorbent. The maximum Cr(VI) removal capacity of the aerogel reached 377.36 mg g⁻¹, the highest one ever reported for biosorbents. It was interesting to note that part of Cr(VI) ions had been reduced to Cr(III) during the adsorption process, which meant that PAMAM-g-CNFs could detoxify Cr(VI).