Synthesis of a novel silica-supported dithiocarbamate adsorbent and its properties for the removal of heavy metal ions

► A new silica-supported dithiocarbamate adsorbent (Si-DTC) was synthesized following a novel synthesis route by anchoring the chelating agent of macromolecular dithiocarbamate (MDTC) to the chloro-functionalized silica matrix(SiCl). ► By adopting this method, it could make more efforts to increase the nucleophilic reactivity of polyamine with carbon disulfide under strong alkaline condition and avoid the degradation of silica matrix. ► The new adsorbent were used to absorb Pb(II), Cd(II), Cu(II) and Hg(II) which are known to be common heavy metal ions from polluted aqueous solutions. ► The dithiocarbamate groups and the amino groups in Si-DTC both take part in the adsorption process for M(II) from aqueous solutions but the adsorption mechanism of Hg(II) onto Si-DTC is quite different from that of Pb(II), Cd(II) or Cu(II) onto Si-DTC, which is testified by the XPS and FT-IR results.