Surface functionalization of cellulose with hyperbranched polyamide for efficient adsorption of organic dyes and heavy metals

Abstract: Cellulose-based adsorbents have attracted much attention in environmentally sustainable pollutant remediation. However, exploring cellulose with efficient adsorption performance remains a challenge. In this study, hyperbranched polyamide (HP) with a subnano-3D architecture and abundant active sites was designed for the surface functionalization of cellulose with the purpose to enhance its adsorption performance. HP functionalized cellulose (HPFC) was successfully fabricated via reductive amination of dialdehyde cellulose (DAC) with HP. The resulting HPFC showed an excellent adsorption performance for orange II (OT) and Cu(II) ions, and the corresponding maximum sorption capacities were 976 and 138 mg/g, respectively. Moreover, the sorption capacities of HPFC were much greater than those of most reported adsorbents. The sorption processes were dominated by the pseudo-second-order and Langmuir models. The adsorption of OT was mainly ascribed to electrostatic interactions, while complexation/chelation played a key role in Cu(II) adsorption. This study may provide a cleaner and sustainable strategy for cellulose functionalization with excellent adsorption performance.