Infrared Spectroscopic Study of Uranyl Biosorption by Fungal Biomass and Materials of Biological Origin

摘要

Metal ion biosorption has been well studied, but the nature of the interactions between metal ions and biomass is still controversial. This paper deals with a description of the influence of pH and sorbent on the removal of uranyl in solution. Infrared spectroscopy allows the influence of amino functions to be characterized for various fungal biomasses such as Aspergillus niger, Penicillium chrysogenum, or Mucor miehei. The binding of uranyl to amine sites confers that it has a structure similar to that of amide. Metal ion sorption is thus examined through its effects on the amide bands. Uranyl sorption changes the relative intensities of the amine or amide bands. Moreover, the UO vibration band appears at a wavenumber that varies according to the pH and the nature of the metal ion species in the solution. As the cell wall, which mainly consists of chitosan or glycoprotein fibers, has been identified as the major site of metal accumulation, the sorption of uranyl by chitosan is studied by spectroscopic studies. Observed differences are explained by the influence of several functional groups in the fungal biomass. The complexation of uranyl by amino ligands such as the monomeric units present in chitin or chitosan (i.e., acetylglucosamine or glucosamine) is governed by the pH.