Synthesis And Adsorption Properties Of Linear Typed Cheating Resin Absorbent Based On Polystyrene

It's well known that the sulfur- and nitrogen-containing chelating resins have excellent adsorption capacities for heavy metal ions. Because of their high affinity towards gold, silver, palladium and mercury, various heterocyclic compounds such as pyridine, pyrimidine and thiazole were introduced into polymeric matrix and the resins obtained were used in the separation and enrichment of the metal ions aforementioned. During the adsorption process, the action between functional groups and metal ions as well as the diffusion of metal ions inside the resins are very important. However, the hydrophilicity of the resins containing sulfur or heterocyclic compounds is poor, which will decrease the adsorption capacity of the resin for metal ions. Otherwise, most functional groups are directly anchored into the matrix through short and rigid chemical bonds and their movements are limited. It's difficult for some rigid functional groups to change configuration and adjust their sites to adsorb metal ions efficiently. If a "spacer" could be attached between functional group and matrix, the functional group would be more flexible and it could flex freely to adsorb metal ions more efficiently. Furthermore, the attachment of the spacer not only can improve the hydrophilicity of the resin but also introduce new functional atoms to improve the adsorption capacities.In this thesis, some novel resins were obtained by anchoring 2-mercaptobenzo-thiazole into crosslinked polystyrene matrix via O, S-containing hydrophilic spacers. The effect of the structures of the resins on the adsorption capacities towards metal ions was also studied.In chapter 1, the progress of chelating resins all over the world was summarized, which was divided into two parts. The first part summarized the natural polymers especially chitosan and cellulose used as chelating resins supporters. The other part summarized polystyrene-supported chelating resins reported since 2000.A novel chelating resin containing sulfoxide and dienol was synthesized using macroporous polychloromethylstyrene-co-divinylbenzene beads as materials and characterized in chapter 2. Water absorption experiments showed that the introduction of sulfoxide and dienol could increase the hydrophilicity of the resin efficiently. The saturation adsorption capabilities of the resin for Hg²⁺, Ag⁺, Cu²⁺, Zn²⁺ and Pb²⁺ were 1.56, 0.75, 0.40, 0.12, and 0.32 mmolg^-1 respectively. In competition condition, this resin had good selectivity for Hg²⁺ and Ag⁺. The kinetic experiment showed that adsorption for Hg²⁺was controlled by ions diffusion at 30 and 35°C and liquid film diffusion at 20 and 25℃.The second novel chelating resin was obtained by anchoring 2-mercaptobenzothiazole into crosslinked polystyrene matrix via polyoxyethylene hydrophilic spacer in chapter 3. The results showed that the resin had good adsorption selectivity for Hg²⁺ and Ag⁺. The addition of polyoxyethylene spacer can increase the ratio of adsorption capability to the content of functional group and the utilization ratio of functional group.The resin incorporating 2-mercaptobenzothiazole (MBZ) into macroporous chloromethylated polystyrene via hydrophilic spacer of polyethylene glycol containing sulfur was synthesized in chapter 4. The results showed that the resin could effectively remove Hg²⁺ and Ag⁺ from solutions containing a large excess of Na+, Mg²⁺, Ca²⁺, Ba²⁺, Cu²⁺, Zn²⁺and Pb²⁺. In column operation, it was observed that Hg²⁺ and Ag⁺ in trace quantities were effectively removed from binary metal ions, the percent recovery of the resin for Hg²⁺ and Ag⁺ were 98.6+% and 97.5+%, respectively.