INFRARED SPECTROSCOPIC STUDY OF URANYL BIOSORPTION BY FUNGAL BIOMASS AND MATERIALS OF BIOLOGICAL ORIGIN

Metal ion biosorption has been well studied, but the nature of the int eractions between metal ions and biomass is still controversial. This paper deals with a description of the influence of pH and sorbent on t he removal of uranyl in solution. Infrared spectroscopy allows the inf luence of amino functions to be characterized for various fungal bioma sses such as Aspergillus niger, Penicillium chrysogenum, or Mucor mieh ei. The binding of uranyl to amine sites confers that it has a structu re similar to that of amide. Metal ion sorption is thus examined throu gh its effects on the amide bands. Uranyl sorption changes the relativ e intensities of the amine or amide bands. Moreover, the UO vibration band appears at a wavenumber that varies according to the pH and the n ature of the metal ion species in the solution. As the cell wall, whic h mainly consists of chitosan or glycoprotein fibers, has been identif ied as the major site of metal accumulation, the sorption of uranyl by chitosan is studied by spectroscopic studies, Observed differences ar e explained by the influence of several functional groups in the funga l biomass. The complexation of uranyl by amino ligands such as the mon omeric units present in chitin or chitosan (i.e., acetylglucosamine or glucosamine) is governed by the pH.