Gd3+ adsorption over a mesoporous silica foam functionalized with poly(amidoamiine)dendrimer

초록

The separation and recovery of rare earth elements (REEs) are critical to meet the ever-increasing demand for REEs extensively used in many high technology devices. For their efficient separation via adsorption, a stable adsorbent with a high adsorption capacity and fast adsorption kinetics is required. The poly(amidoamine) dendrimer (PAMAM) with a threedimensional tree-like architecture possessing a large number of functional nitrogen and amino groups can serve as a chelating agent toward metal ions including REE ions. Herein, the second generation G2 PAMAM dendrimer-grafted mesoporous silica foam and KCC-1 structure (G2/PAMAMMSF and G2/PAMAM-KCC-1, respectively) were prepared and applied as an adsorbent for the recovery of gadolinium ion (Gd3+) from aqueous medium. The prepared adsorbents were characterized by XRD, N2 adsorption-desorption isotherms, FT-IR, XPS, ICP, SEM/TEM EDX-mapping, and elemental analysis to confirm the successful introduction of the functional groups. The adsorption behaviors of Gd 3+ over the materials were examined in detail as a function of solution pH, initial concentration of Gd3+ , and contact time. Finally, adsorption selectivity of Gd 3+ in the presence of competing ions and the reusability of the adsorbents were also investigated.