Ion exchange/complexation of the uranyl ion by Rhizopus biosorbent
Nonliving biomass of nine Rhizopus species effectively sequestered the uranyl ion from solution, taking up 150-250 mg U/g dry cells at 300 ppm U equilibrium concentration in solution, and 100-160 mg U/g dry cells with 100 ppm U in solution. The affinity of this biosorbent for the uranyl ion was found to be affected by timing of harvesting and medium composition. Uptake of the uranyl ion by nonliving biomass of Rhizopus oligosporus was due to ion exchange or complexation, since binding was reversed by the addition of complexing ligands or the reduction of pH to a value less than 2. Uptake isotherms were interpreted in terms of a model of multiple equilibria. At pH less than or equal to 2, or in the presence of NO/sub 3//sup -/, Cl/sup -/, SO/sub 4//sup 2 -/, or EDTA (ethylenediamine-tetra-acetate), the quantity of UO/sub 2//sup 2 +/ that was bound was a constant fraction of that bound at pH 4 in the absence of ligands. This action indicated simple competition for uptake sites between H/sub 3/O/sup +/ and UO/sub 2//sup 2 +/ for uptake sites, or for UO/sub 2//sup 2 +/ between the biomass and ligands in solution. If oxalate or thiocyanate was present, however, the complexed species were sequestered by the biomass. Biomass of Rhizopus arrhizus, which grew as pellets, was subsequently used in a packed sorption column where it exchanged hydrogen ions for uranyl ions (2 H/sup +/ :1 UO/sub 2//sup 2 +/). Concentrated uranyl solutions were eluted in sulfuric or nitric acids, and the biomass was reused eight times with no apparent deterioration of the biosorbent.
- Research Organization:
- McGill Univ., Montreal, Quebec
- OSTI ID:
- 5838577
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 26:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
RHIZOPUS
SORPTIVE PROPERTIES
URANYL COMPOUNDS
UPTAKE
ABSORPTION
ADSORPTION ISOTHERMS
AFFINITY
BIOMASS
CATIONS
CHEMICAL BONDS
CHLORIDES
EDTA
ION EXCHANGE
LIGANDS
MATHEMATICAL MODELS
METABOLISM
NITRATES
PH VALUE
SULFATES
ACTINIDE COMPOUNDS
AMINO ACIDS
CARBOXYLIC ACIDS
CHARGED PARTICLES
CHELATING AGENTS
CHLORINE COMPOUNDS
ENERGY SOURCES
FUNGI
HALIDES
HALOGEN COMPOUNDS
IONS
ISOTHERM
NITROGEN COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLANTS
RENEWABLE ENERGY SOURCES
SULFUR COMPOUNDS
SURFACE PROPERTIES
URANIUM COMPOUNDS
400105* - Separation Procedures