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Title: EXAFS studies of uranium sorption on layer-silicate minerals

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.
Authors:
; ;  [1]
  1. Lawrence Livermore National Lab., CA (United States) [and others
Publication Date:
OSTI Identifier:
214985
Report Number(s):
CONF-950801--
TRN: 96:000922-0480
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: 210. national meeting of the American Chemical Society (ACS), Chicago, IL (United States), 20-25 Aug 1995; Other Information: PBD: 1995; Related Information: Is Part Of 210th ACS national meeting. Part 1 and 2; PB: 1866 p.
Publisher:
American Chemical Society, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 66 PHYSICS; URANIUM; SORPTION; ION EXCHANGE; PYROPHYLLITE; SILICATE MINERALS; VERMICULITE; URANYL CHLORIDES; BOND LENGTHS; MOLECULAR STRUCTURE; ENVIRONMENT