Cadmium Adsorption Using Citrate/Fe(III)、Silicate/Fe(III) Synthetic Iron Oxides
| Autor: | Yuan-Ching Lin, 林鳶青 |
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| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 The objective of this research is to develop the adsorptive material through specific synthetic process. Synthetic processes were divided into two reaction systems, including citrate/Fe(III) and silicate/Fe(III) solutions. And the synthetic conditions of citrate/Fe(III) and silicate/Fe(III) solutions were controlled at pH=8.0, 25℃ and N2 environment. Surface characteristics and microstructures of synthetic iron oxide were investigated, and the adsorption characteristics for metal ions removal were evaluated from water. The quantity of citrate or silicate in synthetic solution was found to have a noticeable effect on the pore size distribution for synthetic iron oxide. Moreover, the macro pores on the surface of synthetic iron oxide decreased after adsorbing cadmium ions. This result indicated that cadmium ions could transport and diffuse into the macro pores on synthetic iron oxide surface, and caused the adsorption reaction. According to XRD analysis result, there was no specific absorption peak appearance on the sample of synthetic iron oxide through the synthetic process under the pure Fe(III) or 0.1 molar ratio of silicate/Fe(III) solution at pH=8.0. The mineralogy of synthetic material prepared by this procedure was verified to be the amorphous iron oxide. However, the mineralogy of synthetic material belonged to the crystalline magnetite through a 0.1 molar ratio of citrate/Fe(III) solution at pH=8.0. Results of kinetic adsorption experiments showed that the best adsorption capabilities of adsorptive material were synthesized under the conditions of 0.1 and 1.0 molar ratio for citrate/Fe(III) and silicate/Fe(III), respectively. And the adsorption efficiencies of cadmium ions for two synthetic materials reached 50~90% and 50~60% at Cd(II)=1.0×10-4M、2.5×10-4M and 5.0×10-4M, pH=6.0, respectively. FTIR analysis result showed that there was a specific absorption peak appearance on iron oxide after reacting with cadmium ions. This result inferred that the adsorptive reaction belonged to form chemical bonding between cadmium ions and iron oxide surface. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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