Synthesis of Functionalized Pamam Dendrimer/Apple Residue Bioadsorbents for Removal of Aqueous Hg(Ii)

Abstract

The pollution of aqueous media with Hg(II) exerts hazardous effect to ecological environment and public health. The design and fabrication of eco-friendly bioadsorbents for efficient removing Hg(II) is a promising strategy. Herein, a series of bioadsorbents were synthesized by the decoration of apple residue with Schiff base functionalized PAMAM dendrimers (SA-G0/AP, SA-G1.0/AP, SA-G2.0/AP). The structures of SA-G0/AP, SA-G1.0/AP, and SA-G2.0/AP were confirmed and their adsorption performance was determined comprehensively by considering various factors. The maximum sorption capacities of SA-G0/AP, SA-G1.0/AP and SA-G2.0/AP are 1.18, 1.73, and 1.88 mmol·g-1 for Hg(II), which are super than most of the reported adsorbents. Moreover, they exhibit marked adsorption selectivity towards Hg(II) with interfering ions of Ni(II), Cd(II), Mn(II), and Pb(II). The as-prepared bioadsorbents also display satisfactory adsorption ability in real water systems and good regeneration property. Adsorption mechanism reveals that the functional groups of O-H, -CONH-, C-N and N=C take part in the adsorption. This work not only provides a pathway to realize the reuse of apple residue, but also opens a promising strategy to construct bioadsorbents for the decontamination of water pollution caused by Hg(II).

Keywords: PAMAM dendrimers, Apple residue, Synthesis, adsorption, Hg(II)