Experimental Study of Uranium(6+) Sorption on the Zeolite Mineral Clinoptilolite

  • PDF / 446,615 Bytes
  • 6 Pages / 414.72 x 648 pts Page_size
  • 31 Downloads / 166 Views

DOWNLOAD

REPORT


EXPERIMENTAL STUDY OF URANIUM(6+) SORPTION ON THE ZEOLITE MINERAL CLINOPTILOLITE

ROBERTO T. PABALAN, J. D. PRIKRYL, P. M. MULLER, AND T. B. DIETRICH

Center for Nuclear Waste Regulatory Analyses, Southwest Research Institute 6220 Culebra Road, San Antonio, TX 78238-5166

ABSTRACT

Experiments on the sorption of uranium(6+) on clinoptilolite from solutions in equilibrium with atmospheric C0 2(g) were conducted to understand the fundamental controls on uranium sorption on zeolite minerals, including the effects of pH, aqueous uranium speciation, and uranium concentration in solution. The results indicate that uranium(6+) species are strongly sorbed on the zeolite mineral clinoptilolite at near-neutral pH. The amount of uranium sorbed is strongly dependent on pH and, to some extent, on the total concentration of uranium. Uranium sorption on clinoptilolite is important in the pH range where U0 2(OH) 2°(aq) is the predominant uranium aqueous species, whereas sorption is inhibited at pH's where carbonateand hydroxy-carbonate-complexes are the primary uranyl species. Surface adsorption appears to be the main sorption mechanism, although at pH