Interactions of aqueous U(VI)with soil minerals in slightly alkaline natural systems

摘要

Uranium(U)is a common contaminant at numerous surface and subsurface sites in proximity to areas involved with weapons manufacturing and atomic energy related activities.This paper covers some important aspects of the aqueous hexavalent uranium [U(VI)] interactions with soil minerals that are present in contaminated soils and sediments.The retention of U via interactions with soil minerals has significant consequences for the prediction of its short-and long-term behavior in soils and geological systems.Studies of the nature and type of these interactions have provided the necessary evidence for assessing the geochemical behavior of U in natural systems under different physical,biogeochefnical,hydrological,and reducing or oxidizing conditions.Over the last 20 years,aqueous U(VI):soil mineral interactions have been studied by geochemists,soil chemists,clay and soil mineralogists,and the progress in some areas is remarkable.Although a mechanistic description and understanding of the complex interactions involving U and soil minerals in natural systems is currently difficult,results from carefully designed and executed field and laboratory experiments with these materials have improved our understanding of the heterogeneous system's behavior and U contaminant mobility and transport.There are,however,areas that warrant further exploration and study.Numerous research publications were reviewed in this paper to present recent important findings to reveal the current level of the understanding of the U(VI)interactions with soil minerals,and to provide ideas for future needs and research directions.