Synthesis of functional poly(amidoamine) dendrimer decorated apple residue cellulose for efficient removal of aqueous Hg(II).

Water pollution caused by Hg(II) exerts hazardous effect to the environment and public health. The design and fabrication of eco-friendly bioadsorbents for efficient removal of Hg(II) from aqueous solution is a promising strategy. Herein, a series of bioadsorbents were synthesized by the decoration of apple residue cellulose with different generation (G) Schiff base functionalized poly(amidoamine) (PAMAM) dendrimers (SA-G0/CE, SA-G1.0/CE and SA-G2.0/CE). The structures of SA-G0/CE, SA-G1.0/CE and SA-G2.0/CE were characterized and their adsorption performances were determined comprehensively by considering various factors. The maximum adsorption capacity of SA-G0/CE, SA-G1.0/CE and SA-G2.0/CE for Hg(II) are 1.18, 1.73 and 1.88 mmol·g, respectively. The as-prepared bioadsorbents exhibit competitive adsorption capacity as compared with other reported adsorbents. Moreover, they exhibit remarkable adsorption selectivity toward Hg(II) with the coexistence of Ni(II), Cd(II), Mn(II), or Pb(II). The bioadsorbents display satisfactory adsorption performance in real water sample and can be reused with good regeneration property. Adsorption mechanism reveals that the functional groups of OH, -CONH-, CN and NC take part in the adsorption for Hg(II). The work not only opens a pathway to realize the reuse of apple residue, but also provides a promising strategy to construct efficient bioadsorbents for the decontamination of Hg(II) from aqueous solution.