Sorption of Perrhenate Ions by a New Anion Exchanger Based on an Oligomer of Epichlorohydrin and 4-vinylpyridine

In this study, oligomer epichlorohydrine (OECH) was crosslinked with 4-vinylpyridin (VP) present initiator of peroxide benzoyl (BP). The resulting anionite (OECH-VP) was characterized by scanning electron microscopy (SEM) and tested for perrhenate ions sorption. The new macropore anion exchange resin was synthesized by polycondensation of epichlorohydrin oligomer and 4-vinylpyridine, the static exchange capacity (SEC) of which is equal to 6.75 mg-equiv∙g-1 in 0.1 M HCI solution and the sorption of perrhenate ions was studied. The influence of the concentration and pH of the model ammonium perrhenate solutions, contact time on the sorption activity of new anion exchangers (ECHO-VP) to perrhenate ions were studied. When studying the concentration effect of NH4ReO4 on the sorption of perrhenate ions by anionite ECHO-VP, the recovery degree at the content of 0.1-0.7 g/L of rhenium remained virtually unchanged and varied between 91- and 92%. When increasing the concentration of rhenium up to 1.02 g/L, the recovery degree (A) is reduced to 86%. The time to reach the equilibrium between the anion exchanger ECHO-VP and the solution of NH4ReO4, containing 0.94 g/L of rhenium and having a pH of 5.1 is 6 hours. Thus in the first 15 minutes 81% perrhenate ions are recovered. Structure of the surface anionite before and after sorption of rhenium ions were studied by electronic microscopy method. The results revealed that the anionite ECHO-VP has a folded surface with a developed system of macropores and the size of macropores was found to vary between 0.70-1.76 mc, and individual pores reach 2.59 mc. It was established that ion exchanger based on oligomers of epichlorohydrin and 4-vinylpyridine have better sorption properties for rhenium (VII) ions that a wide range of commercial sorbents. It was found that the sorption capacity and the extent of new anion extracting the perrhenate ions and reach their maximum values are respectively 371.6 mg∙Re/g and 99% at pH 5.1.