Homogeneous preparation of polyamidoamine grafted silica gels and their adsorption properties as Au3+ adsorbents

• We synthesize a series of low generation dendrimer PAMAM grafted silica gels via the homogeneous method.
• The adsorbents prepared via the homogeneous route showed higher adsorption capacities than those via the heterogeneous route.
• The adsorption capability of the adsorbents did not always increase with the generation number of PAMAM loaded.
• A conformational adsorption mechanism for Au3+ on PAMAM grafted silica gels is proposed.

A series of low generation dendrimer polyamidoamine grafted silica gels (named SiO2-G1.0, SiO2-G2.0, SiO2-G3.0) were synthesized via the homogeneous route. The new materials were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermal analysis, pore and surface area analysis, X-ray diffraction analysis (XRD) and elemental analysis. The adsorption properties of the three products for Au3+ were studied by batch methods. The adsorbents prepared via the homogeneous route showed higher adsorption capacities than those via the heterogeneous route. The maximum adsorption capacities for the three could reach up to 1.48, 2.45, and 2.21 mmol g−1, respectively.

The synthesis of PAMAM dendrimers with silane coupling group.Figure optionsDownload as PowerPoint slide