Surface Complexation Modeling of U(VI) Adsorption by Aquifer

---

Environ. Sci. Technol. 2009 43, 9368–9373

Surface Complexation Modeling of U(VI) Adsorption by Aquifer Sediments from a Former Mill Tailings Site at Rifle, Colorado S U N G P I L H Y U N , * ,† P A T R I C I A M . F O X , ‡ JAMES A. DAVIS,‡ KATE M. CAMPBELL,‡ KIM F. HAYES,† AND PHILIP E. LONG§ University of Michigan, Ann Arbor, Michigan 48109, U.S. Geological Survey, Menlo Park, California 94025, and Pacific Northwest National Laboratory, Richland, Washington 99352

Received July 19, 2009. Revised manuscript received September 30, 2009. Accepted October 28, 2009.

A study of U(VI) adsorption by aquifer sediment samples from a former uranium mill tailings site at Rifle, Colorado, was conducted under oxic conditions as a function of pH, U(VI), Ca, and dissolved carbonate concentration. Batch adsorption experiments were performed using