Studies On The Preparation And Adsorption Properties Of Hydrophilic Resins Functionized With Pyridine Or Thiadiazole Groups

A novel and efficient macroporous adsorbent, which functional group covalently bound to porous polymer matrix can selectively adsorb metal ions and toxic organic compounds from aqueous solution. The functional heterocyclic resins, heterocyclic functional groups grafted onto macroporous polymer with three-dimensional porous structure were synthesized. They have special selectivity and strong adsorbing ability for their highly active heterocyclic functional group, and were extensively used for recovering the precious metal, sewaging wastewater, pharmaceutical separation and purification in recent years.However, most of the present heterocyclic resins have shown slow adsorption speed due to their hydrophobic matrix and low swelling capacity in polar solvent, and their adsorption capacity were restrainted in aqueous solution. In order to overcome the shortcoming of the present heterocyclic resins, three kinds of highly hydrophilic macroporous heterocyclic resins were successfully synthesized in this thesis.1. A hydrophilic resin with 4-aminopyridine was synthesized by the amination of macroporous glycidyl methacrylate-divinylbenzene copolymer (PGMA) beads with 4-aminopyridine. Its static adsorption performance and influence factors toward Hg(Ⅱ), Pb(Ⅱ), Cu(Ⅱ), Zn(Ⅱ) were investigated. At 25℃, the static adsorption capacities for Hg(Ⅱ), Pb(Ⅱ), Cu(Ⅱ), Zn(Ⅱ)are 2.145,1.715,1.023 and 0.654 mmol/g, respectively. The optimal pH value for the adsorption is in the range of 4.5～5.0. In addition, the adsorptive properties for the heavy metal ions could be improved with the increase of temperatures. The adsorption isotherms approximately fit the Langmuirand and Freundlich equations within the range of experimental concentrations.2. Water insoluble crosslinked-chitosan was prepared by crosslinking chitosan microspheres with epichlorodydrin after the amino was protected by benzaldehyde. Then sulfhydryl-containing grafted chitosan polymer was obtained by grafting 2-amino-5-mercapto-1,3,4-thiadizole onto the crosslinked-chitosan. The chitosan polymer (CTS-AMT) was a new hydrophilic functional chelating resin with thiadiazole heterocyclic functional groups. Result obtained from elemental analysis showed that the content of the functional group was 1.62mmol/g. The experimental results showed that CTS-AMT has high adsorption capacity and better adsorptive specificity, and the adsorption process is exothermic. The static adsorption capacity for Hg2+ was 2.54 mmol/g, and the adsorption rate was over 97%.3. Copolymers of 4-vinylpyridine/20% divinylbenzene (P4-VP) were performed via radical suspension polymerization and chemically modified by acrylamide through Michael addition reaction under acidic conditions. Then a novel spherical hydrophilic macroporous adsorption resins (PVP-AM) with amide and pyridine group were prepared. Adsorption property of bisphenol A (BPA) onto the PVP-AM resin was studied via dynamic method. The results showed that the adsorption capacity for BPA in aqueous solution was excellent, and the BPA can be absorbed efficiently by synergy effect of hydrophobic interaction, hydrogen bonding, andπ-πstacking.