Study on Occurrence Speciation and Activity of Uranium Tailing Contaminants in the Presence of S.oneidensis MR-1 under Anaerobic Conditions

Abstract

Taked a uranium tailings pond in Hunan province as the research object, three groups of reaction systems including min (mineral group), min-dbio (mineral-dead bacteria) and min-bio (mineral-viable bacteria) were set up for the sequential batch experiments. The metal elements of U, Fe, Cd, and Pb in the uranium tailings which have reacted with S. oneidensis MR-1 for 2d, 4d, 10d, and 20d were studied by the sequential chemical extraction methods, to analyzed the effect of species of contaminants in Uranium Tailings by S. oneidensis MR-1. The results showed that the residual state is the main occurrence mode of each metal element. The release of contaminants from tailings is mainly attributed to the dissolution of exchangeable state. The complexation or adsorption of the dead bacteria and metal elements leads to the increase of the organic matter. The effect of S.oneidensis MR-1 promoted the release of each metal elements in the exchangeable state, carbonate binding state, organic matter binding state and the amorphous iron manganese oxide binding state of tailings sample, and the reduction of S. oneidensis MR-1 caused U6+ to produce U4+, resulting in an increase in the content of residuals, while Fe3+ was reduced to Fe2+, resulted in an increase in the binding state of crystalline iron-manganese oxides.