The Use Of Nano-iron Mechanism Of Reduction Of Rhenium In A Fixed Soil

As a radioactive element, Technetium is of a long half-life period and complicated chemical behavior, whose oxide-the TcO₄^- ion- endangers the environment horribly by easy transference. However, it is hard to fix the TcO4- ion through regular absorption methods. Hence, this assignment focuses on the methods of reduction that nanometer iron acts on the technetium,as well as the mechanism for the utter destination. Since the physiochemical properties of both Rhenium, which is a non radioactive element and Technetium are the same nearly, it is reasonable to displace technetium with rhenium for text object. Besides, on the base of the reduction, its results and mechanism will be analyzed and argued in this thesis. All the work above helps master the reacting essence theoretically and practically.This thesis firstly introduces the development history and classical preparing methods of nanometer iron powder, furthermore studies the influences from adding surfactants into the reacting system during which, named liquid phase reduction in the laboratory, prepares the zero valence nanometer iron particles, and concurrently finishes the corresponding characterization by apparatus, such as LS, XRD, SEM and etc. Finally, the stabile nanometer iron powder of application is attained. Then within the soil as media, stabile nanometer iron powder prepared already is used to restore the potassium per-rhenium. The removal rate of the ReO₄^- ion is calculated quantitatively in the way of batch text and pillar text under different reacting time and different initial concentrations of the ReO₄^- ion, after being measured and analyzed through spectrophotometry. In the last, it is needed to fit the hypothetical first grade reaction kinetics on the foundation of experiment, and observe the reacting influence of starch quantity added, nanometer iron particles quantity added, initial concentration of ReO₄^- ion, initial pH value of surfactant solution and the temperature.Therefore, the conclusion from this study is drawn up, which is that the relatively sound effect of both restore and reduction comes from the experiment carried out on the ReO₄^- ion in soil, using the stabile effective nanometer iron powder prepared myself in laboratory, in addition, this reaction is accordant with the standard first grade reaction kinetics.