PP Radiation Graft Function Preparation Of Ion Exchange Fibers And Zirconium, Hafnium And Rhenium Ion Adsorption

Due to various application forms and excellent adsorption performance, ionexchange fibers are widely used in element separation and enrichment, environmentalprotection, resource recovery, ect. This paper meanly studied the modification ofpolypropylene woven fabric (pp) and adsorption performance of prepared ionexchange fabric towards zirconium, hafnium and rhenium ions.Electron beam radiation induced grafting of2-vinyl pyridine (2-VP) ontopolypropylene (PP) fibers was investigated by the pre-irradiation method. The effectsof grafting conditions such as solvents, additive, monomer concentration, reactiontime and temperature on grafting yield were studied. The nature of reaction mediumand additive had great influence on grafting yield. Accordingly the optimal reactioncondition is confirmed. Subsequently quatemization of graft copolymers by reactingwith bromoethane was also studied. Results showed that the longer amination timegain the higher conversion ratio.In the FT-IR spectrum of the PP-g-VP fabric, a characteristic peak at1592cm-1and1558cm-1due to—C=N group stretching of poly-VP was observed. Anothercharacteristic peak at1434cm1and1475cm1due to-C＝C group on Pyridinering stretching of poly-VP was also observed. This result indicated the introductionof poly-VP onto PP fabric. In the FT-IR spectrum of the quaterisation of PP-g-VPfabric, a characteristic peak at1630cm-1was observed, but peak at1592cm-1and1558cm-1due to—C=N group stretching became weaker. These results indicated theintroduction of quaternary ammonium group into the PP-g-VP fabric chains.The thermal properties changes of the ungrafted PP, PP-g-VP, and quaterisation ofPP-g-VP were evaluated by differential scanning calorimeter (DSC). The resultsshowed that the thermal behavior of these samples is affected by the grafted sidechains on them. The values of Tmand ΔHmdecreased with increase of grafting yield.The values of Tmand ΔHmof quaterisation of PP-g-VP is smallest.For chelating ion exchange fiber containing pyridine groups, we study its adsoption performance and mechanism towards zirconium and hafnium. Theinfluence of various parameters such as initial concentration, pH, temperature andadsorption time on the adsorption amount for zirconium and hafnium ions wasinvestigated. The adsorption kinetics and thermodynamics were discussed. Theadsorbent with47.4%grafting yield had excellent adsorption capacities for Zr4+andHf4+. The saturation adsorption amount was324.68mg/g and460.83mg/g,respectively.For strong anion exchange fiber containing quaternary ammonium groups, westudy its adsorption performance mechanism towards Rhenium Ions. The influence ofvarious parameters such as initial concentration, pH, conversion ratio and adsorptiontime on the adsorption amount for Rhenium ions was investigated. The results showedthat pH=2.2was the optimal acidity for adsorption of rhenium and the absorptionequilibrium achieved after only20minute. Enthalpy change H was-12.10kJ/molwhich indicated that the adsorption process was exothermic reaction. The adsorbentwith47.4%grafting yield and34.1%conversion ratio had excellent adsorptioncapacities for ReO4-. The saturation adsorption amount was270.3mg g-1.