Theoretical investigation on sulfur-containing chelating resin-divalent metal complexes

摘要

The complex structures and interactions of sulfur-containing chelating resin poly[4-vinylbenzyl-(2-hydroxyethyl)]sulfide (PVBS), poly[4-vinylbenzyl-(2- hydroxyethyl)]sulfoxide (PVBSO), and poly[4-vinylbenzyl-(2-hydroxyethyl)] sulfone (PVBSO_2) with divalent metal chlorides (Cu(II), Ni(II), Zn(II), Cd(II), and Pd(II)) were investigated theoretically. Results indicate that PVBS tends to coordinate with metal ions by sulfur and oxygen atoms forming five-membered ring chelating complexes; while PVBSO and PVBSO_2 prefer to interact with metal ions by the oxygen atom of the sulfoxide or sulfone and hydroxyl group to form six-membered ring chelating compounds. Theoretical calculations reveal that sulfur atoms of PVBS are the main contributor when coordinate with metal ions, while oxygen atoms also take part in the coordination with Cu(II), Zn(II), and Cd(II). As for PVBSO, the oxygen atoms of sulfoxide group play a key role in the coordination, but sulfur and hydroxyl oxygen also participate in the coordination. Similarly, sulfone group oxygen atoms of PVBSO_2 dominate the coordination of Ni(II), Cu(II), and Pd(II), while the affinities of Zn(II) and Cd(II) are mainly attributed to the hydroxyl oxygen atoms. The computational results are in good agreement with the XPS analysis. Combined the theoretical and experimental results, further understanding of the structural information on thecomplexes was achieved and the adsorption mechanism was confirmed.