| Summary: | 碩士 === 國立清華大學 === 生醫工程與環境科學系 === 100 === In the study, the iron containing waste acid was applied to recycle nano iron oxide materials in preparing a Fe/Si absorbent for the adsorption study. The recycled iron oxide material is compatible to reagent grade. It has similar paramagnetic properties and purity. Recently, Magnetic nanoparticles have attracted a great deal of attention due to their versatile applications as in advanced functional materials on high-density recording media, biomedical, magnetic fluids, catalysts and adsorbents etc. Iron oxide nanoparticles have many merits compared to other nanoparticles such as less toxicity, bio compatible and more chemically stable. Hence, it is worthy to address our investigation toward the characteristics of these nanoparticles. Conventionally, iron oxide nanoparticles have been prepared by aqueous solution method, which involved the oxidation and reduction reaction of ferrous and ferric ions. However more and more preparation methodologies have been developed for nanoparticle synthesis. Among those, some are thermal plasma reactions. In this studies, a fast track AC thermal plasma methodology is involved in the synthesis of γ–Fe2O3 and α–Fe2O3 from ferrous waste acid.
During the thermal plasma treatment, the crystallite of γ–Fe2O3 will transform to α–Fe2O3 by the evident of paramagnetic strength disappearance. Therefore we have developed a unique technique to distinguish the ratio of γ–Fe2O3 and α–Fe2O3 in its mixture. Preparation and characterization of silica coated with iron oxides are described in the study. A heterogeneous reaction is employed to coat γ–Fe2O3 and α–Fe2O3 on silica sands (IOCS). The adsorption of heavy metal ions (Cr(VI), Pb(II), Ni(II), Zn(II), Cd(II)) and radionuclides (Co(II), Sr(II), Cs(I)) through modified IOCS is examined. The adsorption result for heavy metals group is strong. As for radionuclide adsorption study, only cobalt has strong adsorption on IOCS surface. Strontium and Cesium are weakly adsorbed on IOCS surface. The plasma vitrefication experiments toward radionuclide adsorbed by IOCS explained the feasibility of radioactivity fixation.
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