A biomimetic SiO2@chitosan composite as highly-efficient adsorbent for removing heavy metal ions in drinking water

Abstract Highly efficient adsorbents for drinking water purification are demanded since the contaminants are generally in a low concentration which makes it difficult for conventional adsorbents. Herein, we present a novel biomimetic SiO 2 @chitosan composite as adsorbent with a high adsorption capability towards heavy metal ions including As(V) and Hg(II). The hollow leaf-like SiO 2 scaffold within the adsorbent has a stable chemical property; while on the surface SiO 2 , the chitosan nanoparticle provide a large amount of active sites such as amino and hydroxyl groups for adsorbing heavy metal ions. The special SiO 2 structure also prevents the agglomeration and loss of chitosan, which enables the efficient contact between the functional groups of chitosan and heavy metal ions. The SiO 2 @chitosan composite exhibits maximum adsorption capacities of 204.1 and 198.6 mg g −1 towards Hg(II) and As(V), respectively. In addition, the removal efficiency reaches over 60% within 2 min. The adsorption performance enables the presented biomimetic adsorbent suitable for adsorbing low-concentration heavy metal ions, especially possessing a promising potential for drinking water purification.