| Summary: | 碩士 === 國立中山大學 === 海洋環境及工程學系研究所 === 94 === This study is to probe into the surface characteristics, crystalline identification and inner structural changes of the synthetic iron oxides which are synthesized from pure Fe(Ⅲ), citrate/Fe(Ⅲ) and silicate/Fe(Ⅲ) solutions at different MRs respectively. This study is also to compare the adsorption capabilities of these synthetic iron oxides serving as the adsorptive materials in containing arsenic wastewater through adsorption experiments. By means of the XRD identification analysis, the synthetic iron oxides of pure Fe(Ⅲ) and silicate/Fe(Ⅲ) are non-crystal ferrihydrite, but the synthetic iron oxide of citrate/Fe(Ⅲ) is crystal magnetite with magnetism. By means of IR spectrum analysis and comparison with the IR spectrum of iron mineral, the FTIR spectrum of pure Fe(Ⅲ) and silicate/Fe(Ⅲ) synthetic iron oxide are similar to that of ferrihydrite; The FTIR spectrum of citrate/Fe(Ⅲ) synthetic iron oxide is similar to that of magnetite. The degree of pore volume and surface area for synthetic iron oxides are as follows: silicate/Fe(Ⅲ) > Fe(Ⅲ) > citrate/Fe(Ⅲ). With the citrate/Fe(Ⅲ) MRs increasing, the pore volume and surface area of synthetic iron oxide will decrease. However, with the silicate/Fe(Ⅲ) MRs increasing, the pore volume and surface area of synthetic iron oxide do not make great difference. Results of kinetic adsorption experiments show that the synthetic iron oxides of citrate/Fe(Ⅲ) or silicate/Fe(Ⅲ) at different MRs will adsorb arsenic better at low pH. With the pseudo-first order and the second order kinetic adsorption model to simulate the adsorption experiment data, the results show that the simulation results are consistent with the pseudo-second order kinetic adsorption model. The equilibrium adsorption experiments show that the adsorption capacity of arsenic for synthetic iron oxides is as follows: citrate/Fe(Ⅲ) > Fe(Ⅲ) > silicate/Fe(Ⅲ), and that the adsorption capacity will decrease with the pH increasing.
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