Facile synthesis of chitosan nanoparticle-modified MnO₂ nanoflakes for ultrafast adsorption of Pb(II) from aqueous solution

Chitosan nanoparticle (CS NP)-modified MnO₂ nanoflakes were presented as a novel adsorbent for fast adsorption of Pb(II) from aqueous solution. Loading dense CS NPs onto mono-dispersive flower-like MnO₂ nanostructures reduces the overlap of CS during adsorption, and thus improves the contact of functional adsorption sites on the surface of MnO₂ nanoflakes with heavy metal ions. The results show that the removal efficiency of the nanoadsorbents reaches up to 93% in 3 min for Pb(II). In addition, the maximum adsorption capacity, effects of adsorbent dosage and pH value, and the reusability were investigated. The kinetic process and adsorption isotherm fit well with the pseudo-second-order model and Langmuir model, respectively. These findings provide a potential strategy to address the overlap issue of some common nanoadsorbents.