Uranium Retardation Capacity of Lithologies from the Negev Desert, Israel—Rock Characterization and Sorption Experiments

Martin A. Dangelmayr, Gilles Y. Bussod, Paul W. Reimus, Giday Woldegabriel, Ran Calvo, Rose J. Harris, Philip H. Stauffer, Hakim Boukhalfa, Ofra Klein‐bendavid, Noa Balaban, Ravid Rosenzweig

Research output: Contribution to journalArticlepeer-review

Abstract

A series of batch experiments were performed to assess the uranium sorption capacity of four mineralogically distinct lithologies from the Negev Desert, Israel, to evaluate the suitability of a potential site for subsurface radioactive waste disposal. The rock specimens consisted of an organic‐rich phospho-rite, a bituminous marl, a chalk, and a sandstone. The sorption data for each lithology were fitted using a general composite surface complexation model (GC SCM) implemented in PHREEQC. Sorption data were also fitted by a non‐mechanistic Langmuir sorption isotherm, which can be used as an alternative to the GC SCM to provide a more computationally efficient method for uranium sorption. This is because all the rocks tested have high pH/alkalinity/calcium buffering capacities that restrict groundwater chemistry variations, so that the use of a GC SCM is not advantageous. The mineralogy of the rocks points to several dominant sorption phases for uranyl (UO22+), including apatite, organic carbon, clays, and iron-bearing phases. The surface complexation parameters based on literature values for the minerals identi-fied overestimate the uranium sorption capacities, so that for our application, an empirical approach that makes direct use of the experimental data to estimate mineral‐specific sorption parameters appears to be more practical for predicting uranium sorption.

Original languageEnglish
Article number728
JournalMinerals
Volume12
Issue number6
DOIs
StatePublished - 1 Jun 2022
Externally publishedYes

Keywords

  • Langmuir sorption isotherm model
  • geochemistry
  • nuclear waste disposal
  • reactive transport modeling
  • sorption
  • surface complexation model
  • uranium

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Geology

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