Adsorption performance of sulfur-decorated polyamidoamine dendrimers/silica for Ag(I) and Cu(II)

Water pollution aroused by heavy metal poses great damage to environmental safety. Polyamidoamine (PAMAM) dendrimers display great advantages in preparation efficient adsorbents to decontaminate heavy metal ions. Herein, sulfur-decorated PAMAM dendrimers/silica (G0-MT, G1-MT and G2-MT) were constructed by using alkoxysilyl-containing PAMAM dendrimers as precursor. G0-MT, G1-MT and G2-MT were employed for removing Ag(I) and Cu(II) from water solution. The adsorption capacity for Ag(I) and Cu(II) follows the order of G0-MT < G2-MT < G1-MT and G0-MT < G1-MT < G2-MT, respectively. The maximum adsorption capacity of the composites for Ag(I) and Cu(II) are 1.38 and 0.78 mmol g−1, which are superior to the corresponding adsorbents that synthesized by chemical modification method. Adsorption kinetic indicates the saturated adsorption for Ag(I) and Cu(II) can be reached at 150 and 270 min. The adsorption for the ions could be boosted by raising metal ion concentration and adsorption temperature. Adsorption mechanism demonstrates S atoms dominate the adsorption, while O and N atoms participate in the adsorption. The noticeable adsorption capacity and regeneration property enable the composites to be promising candidate for efficient removing aqueous Ag(I) and Cu(II).