Polypropylene Modified with Amidoxime/Carboxyl Groups in Separating Uranium(VI) from Thorium(IV) in Aqueous Solutions

Abstract

A majority of U/Th reprocessing studies are hampered in the production of large amounts of radioactive waste during extraction with organic complexes from highly acidic solutions. Polypropylene grafted with amidoxime/ carboxyl groups (PPAC), which exhibits selective binding toward U(VI), can help reduce organic waste. Batch studies on PPAC separating U(VI) from U(VI)/Th(IV) mixture in acidic to weak alkaline solution with complexing agent EDTA were carried out. The result suggested a much better affinity of PPAC to U(VI) over Th(IV). The pH effect study suggested the largest U/Th mass ratio at pH ∼8. FTIR spectra at different pHs indicated most of the carboxyl and amidoxime functional groups were protonated at lower pH, while with increasing pH, the deprotonating degree increased correspondingly. X-ray diffraction analysis showed U(VI) and Th(IV) could both enter the crystal lattice, resulting in smaller diffraction angle which was associated with U(VI) and Th(IV) adsorption capacity. This work revealed polymer or other material with amidoxime/carboxyl groups is a promising candidate for deployment as a uranium adsorbent in U/Th reprocessing.

Plasma-induced grafting of acrylic acid on bentonite for the removal of U(VI) from aqueous solution

“…A higher percentage of U(VI) can be removed with increasing amount of adsorbent due to the increased active sites. By comparing the adsorption percentage, the higher adsorption capacity of the AA-g-BT composite was observed, especially within the adsorbent amount from 0 to 1.5 g l −1 , which can be ascribed to the active carboxyl functional groups from AA by plasma treatment [34]. Different from the increasing adsorption percentage, a decreased distribution coefficient was obtained with increasing adsorbent amount, which is similar to that previously reported [35].…”

Polymer brushes on graphene oxide for efficient adsorption of heavy metal ions from water

“…The hydrophilic nature will allow PAO brush grafted graphene to facilely capture the heavy metal ions from water, 65,66 and therefore enhance adsorption performance. To illustrate the hydrophilic nature of the PAO brush grafted GO, the macroscopic wetting characteristics were examined via water contact angle measurement.…”

Polymer sequestrants for biological and environmental applications

“…The effect of temperature on the adsorptive behavior of U(VI) and Th(IV) at pH 4 and 6 was also examined at temperatures of 25, 35 and 45 °C. The adsorption of U(VI) was almost unchanged over the temperature range while the adsorption of Th(IV) increased with temperature at both pH values, but remained lower than that of U(VI) …”

“…) was synthesized via gamma irradiation of polypropylene followed by graft polymerization with a 4:1 mass ratio of acrylonitrile to methacrylic acid. Conversion of the polypropylene‐ g ‐acrylonitrile‐ co ‐methacrylic acid to PPAC was accomplished via reaction with hydroxylamine …”