Feasibility studies of decontamination agent for radioactivity metals

• Main Authors: Tzu-Ling Tang, 唐慈翎
• Other Authors: Chang-Pin Chang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/18381193199276738143

碩士 === 國防大學理工學院 === 應用化學碩士班 === 97 === Take Taiwan as an example, more than 90% of the radioactive wastes come form the nuclear energy plant. At present, the main treatment method of radioactive wastes is storing for a long time. Therefore, one of important work is decommission of nuclear energy plant or replacement of the radioactive metal pipe fittings and machinery. It can improve radioactive waste decrement, resource recovery, human health, and safety work. In this research, different chelating agents have dissimilar ability of chelating various type metals. Looking for a variety of chelating agents likes Salicylic acid and EDTA proceed to the coordination reaction in aqueous solution with the main composition of iron rust, Fe2O3‧H2O to reach better decontamination ability. Using the auxiliary of oxidants can help divalent iron ions oxidized into trivalent iron ions and change pH value of aqueous solution to look for the best conditions for decontamination. Using the UV-Vis spectrometer identifies the characteristics of absorption peaks and the change in absorbance after chelating agent chelate the iron ions. Absorption peak value after chelating is significant increase and generating displacement situation of peak. In the experiment of adjusting the pH value of aqueous solution, the absorption value is the non-response, when salicylic acid in alkaline aqueous solution. It should be processing precipitation of Fe (OH)3 because the [OH]－concentration increased reaction with the Fe3+. When using salicylic acid as the chelating agents with antioxidant, the better condition of decontamination is keep pH value in 2.5 ~ 4.0 of aqueous solution. EDTA as a chelating agent adjusting pH value of 4.0 ~ 6.0 is best.