Uranyl adsorption in multi-mineralic systems: Devitrified tuff and granite

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:370468

Ong, C G; Leckie, J O ^[1]

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1. Stanford Univ., CA (United States)

Earth materials including a devitrified tuff ({approximately}64% feldspar) and a granite ({approximately}66% feldspar) were pulverised and used in pH sorption edge batch experiments involving uranyl ion (10{sup -6} M total uranyl concentration, 1 g/L solids concentration, 0.1 M NaCl background electrolyte, 25{degrees}C, and CO{sub 2}-free using an Ar blanket). Surface treatments, intended to facilitate to various extents the dissolution of Al and Si from mineral phases, of the earth material suspensions prior to the addition of uranyl included: (1) equilibration in the electrolyte solution for a few days, (2) exposure to electrolyte solution for about a month during which the supernatant was periodically removed and replaced by fresh 0.1 M NaCl solution, and (3) equilibration in electrolyte solution without supernatant exchange in parallel with the second set. The uranyl sorption edge exhibited uptake increasingly from about pH 4 to 7, with about 50% uptake occurring at about pH 5.5. Above pH 7, uranyl desorption is observed and the rate of decline with pH is dependent on the surface treatment. Similar sorption behavior is exhibited by the single mineral albite.

• OSTI ID: 370468
• Report Number(s): CONF-960376--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ADSORPTION
MINERALS
PH VALUE
RADIOACTIVE WASTES
RADIONUCLIDE MIGRATION
SORPTIVE PROPERTIES
SURFACE TREATMENTS
TUFF
URANYL COMPOUNDS