Synthesis Of Manganese Oxide Nanostructures And Their Adsorption Properties For Radionuclides

Radioactive nuclear waste water,the by-product of the rapid development of nuclear industry has brought serious harm to the environment and human life.At present,using adsorption method to treat radioactive contaminated waste water is an effective remedy.However,the key step in adsorption method is the selection towards adsorbent materials.Among the adsorbents,metallic oxide nanomaterials have attracted wide attention due to the advantages of their unique stable structures and high adsorption efficiency.Manganese oxide as an important component of metallic oxide,the research on its preparation of nano-scaled materials and adsorption performance for radionuclides is rarely discussed.（1）In the dissertation,one-dimensional manganese oxide Na_0.44Mn O₂ nanoribbons were prepared by the molten-salt method,the morphology and structure of the samples were characterized by XRD,SEM,TEM and other testing methods.The SEM figure shows the uniform ribbon-like structure of the sample.The results of adsorption experiment of radionuclide uranium show that when 0.10 g Na_0.44Mn O₂ was added into15 m L solution with 36 mg/L uranium concentration,the removal rate of radionuclide uranium was higher than 97%.When the initial concentration of uranium in solution increased from 0 to 1000 mg/L,the adsorption capacity of Na_0.44Mn O₂ nanoribbons for uranium ions also increased.The adsorption kinetics and adsorption isotherm analysis indicate that the adsorption is mainly monolayer chemisorption.The experiment data fits well to the Langmuir model with a correlation coefficient R_L² over 0.99,corresponding to maximum adsorption capacity of 203.27 mg/g.（2）Then the adsorption properties of manganese oxide K_2-xMn₈O₁₆ nanomaterials were investigated.One-dimensional K_2-xMn₈O₁₆ nanomaterials were prepared by the molten-salt method,and its morphology and structure were characterized by XRD,TEM and other methods.The results of TEM show that the structures of K_2-xMn₈O₁₆ and Na_0.44Mn O₂ are similar,both of the materials composed uniform one-dimensional nanostructures.The adsorption experiments of uranium ions by K_2-xMn₈O₁₆ nanoribbons show that the uranium ions can be highly adsorbed by adding 45 mg K_2-xMn₈O₁₆nanoribbons in the uranium solution with low concentration,and the adsorption rate can be as high as 95%.In addition,the adsorption capacity of the K_2-xMn₈O₁₆ nanoribbons is also affected by the concentration of uranium in the solution,and the adsorption capacity increases with the increase of the initial concentration of uranium ions in the uranium-containing solution from 0 to 950 mg/L.The adsorption kinetics and isothermal adsorption analysis show that the adsorption principles of K_2-xMn₈O₁₆ and Na_0.44Mn O₂nanoribbons are different to some extent.The adsorption of uranium ions by K_2-xMn₈O₁₆materials is a combination of chemical adsorption and physical adsorption.The experimental data of K_2-xMn₈O₁₆ nanoribbon on uranium in solution at different concentrations fit well with Langmuir model,the linear correlation coefficient R_L² is greater than 0.99,with the corresponding maximum adsorption capacity to be 158.48mg/g.Figure[24]Table[6]Reference[131]...