Study On The Effect And Mechanism Of Leifsonia Sp. On Remove Of Zero Valent Iron To Uranium In Aqueous Solution

With the rapid development of nuclear energy and the increasing demand for uranium resources,the amount of uranium mining and processing increases continuously,and the resulting tailings and tailings also increase gradually.Under the influence of the external environment,the uranium in the tailings pond will be released into the environment again,seriously threatening the ecological security and human health around.In this paper,ZVI and Leifsonia sp.two fixatives are used to immobilize uranium in uranium wastewater.The effects of dosage,contact time,pH and initial uranium concentration on removal U?VI?by ZVI and ZVI+Leifsonia sp.were investigated by batch experiments.Stability was analyzed by desorption test.A response surface method was used to optimize the condition of Leifsonia sp.uranium removal.The mechanism of the removal of U?VI?by ZVI,ZVI and Leifsonia sp.was discussed by means of SEM-EDS,FTIR,XPS and XRD characterization.Test results of the removal of U?VI?by ZVI showed that the removal efficiency of uranium reached 97.12%when the dosage was 1 g/L,pH=5,the contact time was 2 h,C₀=10 mg/L.Characterization analysis showed that a large number of spherical and lamellar precipitates appeared on and around the ZVI surface after the reaction with uranium,and the functional groups interacting with U?VI?were mainly hydroxyl,carboxyl and so on.Test results of the removal of U?VI?by ZVI+Leifsonia sp.showed that the removal efficiency of uranium reached 98.81%when the dosage was1 g/L?pH=5,the contact time was 48 h,C₀=10 mg/L.When ZVI dosage is<1 g/L?pH<5 or pH>6,the addition of Leifsonia sp.significantly promoted the removal U?VI?by ZVI.Desorption test showed that Fe-U and Fe-Leifsonia sp.-U had certain stability.SEM-EDS,FTIR,XPS and XRD characterization analysis showed that the cell surface was attached to a tight scale-like sediment after the reaction with uranium,and the functional groups interacting with U?VI?were mainly hydroxyl,carboxyl and phosphate groups.The precipitate may contain Bassetite?Fe?II??UO₂?₂?PO₄?₂·8H₂O?and Bituminous uranium ore-UO_2.2,etc.In summary,ZVI and ZVI+Leifsonia sp.have high removal performance for uranium solution.Leifsonia sp.has positive effects on the removal of U?VI?by ZVI?Biosorption and Biomineralization?.