Synthesis And Adsorption Properties Of Amino-pyridine Chelating Resins Containing Sulfur, Sulfoxide, Sulfone

Being an important branch of the polymer science, the chelating resin is a kind of cross-linked functional polymer material, which can form multi-coordinated complex with metal ions. This kind of resin is widely used in the fields of inorganic, metallurgy, analysis, radiation, pharmaceuticals, catalysis, and marine chemistry, etc. Cross-linked polystyrene is one of the most popular skeletons of the chelating resins, but it has the bad hydrophilic; Commonly, sulfur-containing chelating groups, as soft bases, have good adsorption properties for transition metal ions, but they have some hydrophobic properties; pyridine is often used as function group of chelating resin due to its nitrogen atom which can form steady complex with transition metal ions. Moreover, Amino-pyridine can be easily linked to macromolecule carrier through amino group. So that three kinds of novel chelating resins named PVBS-AP,PVBSO-AP,PVBSO2-AP are synthesized by chloromethylated polystyrene. The structure and patterns are characterized by FTIR, XPS, SEM, ES, etc.. The adsorption properties of the three resins for Hg²⁺,Ni²⁺,Pb²⁺,Fe³⁺,Au³⁺,Cu²⁺,Pd²⁺,Cd²⁺,Pt4+,Zn²⁺,Ag+ were studied.The results showed that the resin of PVBS-AP had good adsorption for Hg²⁺,Pd²⁺,Au³⁺,Pt4+,Ni²⁺; the resin of PVBSO-AP had good adsorption for Hg²⁺,Ni²⁺,Pb²⁺,Au³⁺,Cu²⁺,Pd²⁺,Cd²⁺,Pt4+;the resin of PVBSO2-AP had good adsorption for Ni²⁺,Cd²⁺,Pb²⁺,Cu²⁺; the three resins all had good selective properties for Au³⁺, Ag+ and Hg²⁺when the coexisting ions were Ni²⁺,Pb²⁺,Cu²⁺ , Zn²⁺; The experience results also told us that the adsorption properties of PVBS-AP and PVBSO-AP were little affected by acid concentration, except for the resin of PVBSO2-AP; the result of the adsorption kinetics for Hg²⁺ showed that the balance speeds of PVBS-AP and PVBSO2-AP were faster than PVBSO-AP; The thermodynamics results showed that the adsorption of the three resins for Hg²⁺ were good agreement with the Langmuir equation; and all the three resins had good reuseability.The adsorption mechanisms of the resins for Hg²⁺ and Ag+ were confirmed by X-ray photoelectron spectroscopy (XPS). The result showed that the nitrogen atoms of amino-pyridine were that main electron donors to coordinate with Hg²⁺ and Ag+ in the three resins. The sulfur atoms in the spaces of the PVBS-AP and PVBSO-AP resins took part in coordinating with metal ions. Because of the hydrophilic chain increasing the hydrophilicity of the chelating resins, the novel amino-pyridine chelating resins containing sulfur, sulfoxide, sulfone spacers have good adsorption for the transition metal ions .They can be well used to extract and separate some transition metal ions.