| Nowdays, nuclear energy as a type of green energy, is treated as a better solution and show important role for energy shortage. However, in the process of its utilization, high risk is hidden around the world. In the development process of nuclear power, the effective disposal technique of radioactive waste which contains wastewater appears especially important. As an adsorbent material, chitosan and its deviants has the advantage of non-toxicity, easy degradation and no extra pollution. All these above advantages are expected chitosan and its deviants to develop as an environmental eradicator.Objective:By discussing the coordination between different ligands and metal ions, the perfect coordinating group could be screen out. Through the method of changing the character of the group, the adsorption of radionuclide uranium and thorium with chitosan and its derivants were adjusted and the optimal adsorptive situation was confirmed. By enclosing the magnetic chitosan particle to the adsorbent material, to solve the difficulty of separation and reusing research from different radio eradicator medium. In this paper, the physic-chemical characterization of chitosan and its derivants were analyzed, including their adsorption, which provided not only the theoretical basis but also the experimental evidence of adsorbent material for high-efficiency reusing research.Method:Some physico-chemical characteristics of chitosan were studied by several methods to control degree of deacetylation (DD), the degree of polymer (DP) by acid-base titration, infrared spectroscopy and mass spectrometric analysis respectively. By ultraviolet-visible spectrometry, spectrum analysis was performed in composition of Cu2+, Ni2+, Co2+ with different ligands such as amino acid, chitosan and citric acid etc. Combined with the adsorption of radionuclide uranium and thorium with chitosan and its derivants, the best adsorption condition could be confirmed. Magnetic chitosan particle was prepared by precipitation. Through the scan electro-microscope the configuration and the shape of the particle was analyzed. Physical phase of the magnetic characteristic particle was analyzed by XRD. Contrast the adsorption of radionuclide uranium and thorium with chitosan and its magnetic derivants under the best adsorptive condition.Result:1. By ultraviolet-visible spectrometry, scan the coordinated composition of Cu2+ Ni2+ and Co2+ with some ligands such as amino acid, chitosan and citric acid etc. By overview the absorb peaks, the perfect coordination was found between Cu2+ and amino acid. The coordinated capability was increased according to the order of chitosan, glucosamine and amino acid.2. The degree of deacetylation test of chitosan by acid-base titration was detected as 90.1%. IR spectrum analyzed the acetyl and amino group, the degree of deacetylation and degree of polymer were observed by MALDI-FT-MS respectively. Further information was confirmed by these spectra.3. By the research of the adsorption, chitosan showed high adsorption of radionuclide uranium. The adsorption ratio was obtained more than 96%. Even under the exist condition of large amount of Cu2+, the adsorption was still particularly high. In the meanwhile, chitosan showed high adsorption of radionuclide thorium.4. The magnetic chitosan particle prepared by precipitation showed regular shape by electro-microscope. Reviewing the scan electric-microscope showed of Fe3O4, most grains were even distributed, and surface smooth, shape similar with roundness, size was about 200～300nm. The scan electric-microscope of Fe3O4@SiO2 showed the grains were even distributed and in good order, homogeneous texture, which size was around 500nm. In the enwraped of the chitosan, Fe3O4 had no effect, which still kept proper crystalization.5. By the contrast analysis, the adsorption of radionuclide uranium and thorium with magnetic chitosan particle was lowered, but still showed perfect adsorption of these radionuclides.Conclusion:1. In the research, the ligands such as -NH2,-OH,-COO- were found to be coordinated with metal ions. The ligand with amino group indicated strong ability of coordination. The coordinated capability was increased according to the order of chitosan, glucosamine and amino acid.2. Chitosan showed high adsorption of radionuclide uranium. Even under the exist condition of large amount of Cu2+, it still displayed proper adsorption. Meanwhile, it also had good adsorption of thorium.3. After cross-linking and enwrapping the magnetic particle, the magnetic chitosan particle still kept proper adsorption of the radionuclide uranium and thorium. The new magnetic material was very convenient to separate and recycle from the decontamination medium. |
PDF Full Text Request