Combined theoretical and experimental study on the adsorption mechanism of poly(4-vinylbenzyl 2-hydroxyethyl) sulfide, sulfoxide, and sulfone for Hg(II) and Pb(II)

摘要

The adsorption mechanism of poly(4-vinylbenzyl 2-hydroxyethyl)sulfide(PVBS), sulfoxide (PVBSO), and sulfone (PVBSO2) for Hg(II) and Pb(II) were determined by density functional theory (DFT) method. It is showed that PVBS chelates with Hg(II) and Pb(II) by S and O, while PVBSO and PVBSO2 complex with Hg(II) and Pb(II) by hydroxyl oxygen, sulfoxide and sulfone oxygen. The resins exhibit higher binding energies for Hg(II) than Pb(II), and follow the order of PVBS > PVBSO > PVBSO2. NBO analysis demonstrates charge transfer from PVBS, PVBSO, and PVBSO2 to Hg(II) and Pb(II) occurred during the adsorption. The interaction of S with metal ion dominates the adsorption of PVBS, whereas the sulfoxide and sulfone oxygen plays more important part in the adsorption of PVBSO and PVBSO2. Combine with the experimental results, the adsorption mechanism is well elucidated. (C) 2016 Elsevier B.V. All rights reserved.