Adsorption of VO2+ by poly[(tetrafluoroethylene)-co-(perfluorovinyl ether)] copolymer grafted with acrylic acid usingγ-irradiation

Abstract

Grafted films were prepared by the reaction of acrylic acid (AAc) onto poly[(tetrafluoroethylene)-co-(perfluorovinyl ether)] copolymer (PFA) using γ-irradiation by the mutual technique. The grafted copolymer was complexed with the vanadyl group, VO2+, in aqueous solution. The grafted copolymer–metal complexes were examined by infrared and ultraviolet spectrometry, energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The amount of vanadium in the grafted films was estimated using EDS. The thermal stability of the films was investigated through thermogravimetric and differential scanning calorimetry measurements. The degree of crystallinity of the grafted and complexed films decreased by treatment with VO2+ ions and also by heating at 300 °C. When heated at a temperature above 300 °C, the grafted chains degraded till they disappeared and the original polymer was almost completely separated. XRD investigation revealed that the metal oxide may be formed as a separate phase with subsequent decrease in the crystallinity of the copolymer. Furthermore, scanning electron microscope (SEM) investigation of the grafted and modified films, both unheated and heated (300 °C), showed changes in the structure and morphology. The tendency of the graft copolymer to adsorb and/or bind to VO2+ from aqueous solution is of promising use in the field of waste treatment of rare metals in the environment. Copyright © 2004 Society of Chemical Industry