title: Effects of ammonium on uranium partitioning and kaolinite mineral dissolution.
abstract: Ammonia gas injection is a promising technique for the remediation of uranium within the vadose zone. It can be used to manipulate the pH of a system and cause co-precipitation processes that are expected to remove uranium from the aqueous phase and decrease leaching from the solid phase. The work presented in this paper explores the effects of ammonium and sodium hydroxide on the partitioning of uranium and dissolution of the kaolinite mineral in simplified synthetic groundwaters using equilibrium batch sorption and sequential extraction experiments. It shows that there is a significant increase in uranium removal in systems with divalent cations present in the aqueous phase but not in sodium chloride synthetic groundwaters. Further, the initial conditions of the aqueous phase do not affect the dissolution of kaolinite. However, the type of base treatment does have an effect on mineral dissolution.
authors.affiliation: Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL 33174, United States. Electronic address: hemerson@fiu.edu.
authors.forename: Hilary P
authors.initials: HP
authors.lastname: Emerson
authors.affiliation: Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL 33174, United States.
authors.forename: Silvina
authors.initials: S
authors.lastname: Di Pietro
authors.affiliation: Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL 33174, United States.
authors.forename: Yelena
authors.initials: Y
authors.lastname: Katsenovich
authors.affiliation: Environmental Systems Group, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, United States.
authors.forename: Jim
authors.initials: J
authors.lastname: Szecsody
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry*; D060587:Groundwater; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000737:chemistry*; D008903:Minerals; D008956:Models, Chemical; D012995:Solubility; D014501:Uranium / Q000032:analysis / Q000737:chemistry*; D014875:Water Pollutants, Radioactive / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D008903:Minerals; D014875:Water Pollutants, Radioactive; D007616:Kaolin; D014501:Uranium
keywords: Ammonia gas; Remediation; Uranium