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EXAFS studies of uranium sorption on layer-silicate minerals

Conference ·
OSTI ID:214985
; ;  [1]
  1. Lawrence Livermore National Lab., CA (United States); and others
The local structure of uranium sorbed on mineral surfaces was investigated by uranium L{sub 3}-edge EXAFS. Solutions of uranyl chloride, UO{sub 2}Cl{sub 2}, were exposed to vermiculite, an expansible layer silicate mineral, under conditions which favor sorption by either cation exchange or surface complexation. EXAFS of the resulting mineral samples indicates a larger distortion of the uranyl equatorial shell for cation exchange, possibly due to steric effects of interlayer sorption. The uranyl U-O axial bond distance is greater for surface complexation than for ion exchange. Uranyl sorption on talc and pyrophyllite, layer silicate minerals with essentially no cation-exchange capacity, gives results which generally support the trends for surface complexation on vermiculite.
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
214985
Report Number(s):
CONF-950801--
Country of Publication:
United States
Language:
English