Compressible nanowood/polymer composite adsorbents for wastewater purification applications

Abstract Heavy metal pollution has raised serious concerns due to the potential threat to public health and the environment. Adsorption is an important method for removing metal ions from wastewater, but many current adsorbents are limited by high cost, low adsorption efficiency and poor cyclability. Herein, a compressible composite (PEI-NW) with a porous structure is prepared by a simple chemical treatment of nanowood (NW) with polyethyleneimine (PEI). Modification of NW with PEI enables the efficient adsorption of metal ions. PEI-NW shows excellent adsorption efficiency. Adsorbed heavy metal ions can be rapidly desorbed by simply immersing PEI-NW in a desorption solution. PEI-NW can be reused by employing the squeezing method because of its excellent compressibility. The adsorbent can remove the heavy metal ions from polluted water with 60% of adsorption efficiency even after 50 adsorption-desorption cycles. This compressible composite provides new insights for the design of efficient cleaners for heavy metal ion removal and offers approaches to the development of functionalization of biomass-based composites.