Study On The Preparation,Performance And Application Of Praseodymium Ion Imprinted Polymer

Praseodymium is a very important rare earth elements(REEs), and has been used widely in petrochemical, permanent magnetic material and fiberthe field. Therefore, it’s very significant to study the separation and enrichment technique for praseodymium. Based on a large number of literature consulted, Pr(Ⅲ) ion imprinted polymers was considered to be prepared as the material for separation and enrichment of praseodymium based on the fact that the ion imprinted polymer possess specific recognition ability and larger adsorption capacity to the target ion. The specific content was summarized as follows:1. The interaction between Pr(Ⅲ) and functional monomers (acrylamide (AM), methacrylic acid (MAA),4-vinyl pyridine (4-VP)) and three functional monomers (2-allyl thiol nicotinic acid (ANA), N-Allylurea (NAU),2-acetyl amino acid (AAA)) in prepolymerization system was studied by fluorescent spectrophotometry. The binding constant and molar ratio of Pr(Ⅲ) with the functional monomers were calculated and the groups of functional monomers participated in the coordination to Pr(Ⅲ)were deduced. The results indicate that all of the functional monomers can bind with Pr(Ⅲ) using O、 N or S, and the maximum binding constant can be obtained with AAA and4-VP as7.9×108and6.3×1013, respectively.2. After the conditions of polymerization reaction liked the types of functional monomer together with the amounts of functional monomer, cross-linking agent and solvent were optimized, a Pr(III)ion-imprinted polymer (IIP42) with excellent adsorption properties was obtained,which was prepared by precipitation polymerization using AAA as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker. The molar ratio of the template, the monomer and the cross-linker was1:4:20. In the solution which the concentration of Pr (Ⅲ) was0.5mmol/L, the optimum polymer possessed13.76mg/g as the adsorption capacity and1.61as the imprinting factor. The maximum adsorption capacity of IIP42is obtained as48.27mg/g by Scatchard analysis. IIP42was characterized by the FT-IR spectrum and the scanning electron microscope(SEM). Lastly, IIP42was used as the absorbent material of the SPE. The conditions of the solid phase extraction were optimized. At the optimizational extraction conditions, Pr(III) can be extracted by the solid phase extraction based ion-imprinted polymers with the extraction percentage of71.4%, while the extraction percentage for the other precious metals all is below21%.3. Pr(Ⅲ) as the template was added into the acetic acid solution which had dissolved the chitosan. Then the baed could be formed by dropping the solution into the sodium hydroxide solution. The formalin and the epichlorohydrin were used as cross-linker. The concentration of the template, the acetic acid solution, the formalin and the epichlorohydrin were optimized. A Pr(Ⅲ) ion-imprinted polymer chitosan surface imprinted technique (CTS-IIP16) with excellent adsorption properties was obtained. In the solution which the concentration of Pr(Ⅲ) was0.5mmol/L.The static adsorption capacity of CTS-IIP16is17.368mg/g together with the imprinting factor of1.78. The maximum adsorption capacity of CTS-IIP16is obtained as176.95mg/g by Scatchard analysis. CTS-IIP16was characterized by the FT-IR spectrum and the scanning electron microscope(SEM),and the static adsorption experiment was used to evaluate its practicability.The results indicated that CTS-IIP16had uniquely selectivity for Pr(Ⅲ) and could be used repeatly at least5times when using2.0mol/L HCl as desorption agents.4. A novel Pr(Ⅲ) ion-imprinted polymer (T-IIP33)was obtained by using AAA as functional monomer, nano-TiO2as supporter,EGDMA as crosslinker and AIBN as initiator under the mole ratio of Pr(Ⅲ),AAA and EGDMA as1:5:40. In the solution which the concentration of Pr (Ⅲ) was0.5mmol/L, the optimum polymer possessed18.24mg/g as the adsorption capacity and1.8as the imprinting factor. The maximum adsorption capacity of T-IIP33is obtained as97.1mg/g by Scatchard analysis. T-IIP33was characterized by the FT-IR spectrum and the scanning electron microscope(SEM). Lastly, T-IIP33was used as the absorbent material of the SPE. The conditions of the solid phase extraction were optimized. At the optimizational extraction conditions, Pr(Ⅲ) can be extracted by the solid phase extraction based ion-imprinted polymers with the extraction percentage of80.2%, while the extraction percentage for the other precious metals all is below22%.