Facile synthesis of EDTA grafted 3D spherical-chain porous silica with high capacity for rapidly selective adsorption of Cu(II) from aqueous solutions

The highly efficient adsorbents with fast adsorption rate, high adsorption capacity and selectivity as well as good reusability were successfully synthesized through fabricating 3D spherical-chain porous silica material and grafting modification with ethylenediaminetetraacetic acid (EDTA) for the selective removal Cu(II) from wastewater. The obtained adsorbents were characterized by XRD, FT-IR, SEM, TEM, XPS, N 2 adsorption–desorption and back titration. The results indicate that the 3D framework structure is adjustable in a certain range by varying the parameters of the synthesis system. And the adsorption performance of the materials was investigated under different conditions such as pH, contact time and initial metal ions concentration. Under the experiment conditions, the synthesized adsorbent is efficient in removing Cu(II) and the adsorption equilibrium could be achieved within only 5 min, and the kinetic data are well fitted by pseudo-second-order and Langmuir isotherm models. The prepared adsorbents display good selective adsorption of Cu(II) and can be feasibly regenerated without evident decrease even after five recycles. Basing on the obtained results, the plausible adsorption mechanism was proposed and analyzed.