| Summary: | 碩士 === 國立宜蘭大學 === 環境工程學系碩士班 === 99 === Phosphate is one of the main contaminants responsible for the eutrophication of surface waters, and adsorption is a potential treatment method of this pollutant. A magnetic adsorbent manufactured from magnetite (Fe3O4) can be easily recovered from treated water by magnetic force, without requiring further downstream treatment. In this research, the surface of magnetite modified with aluminum and silica (Al/SiO2/Fe3O4) was used to adsorb phosphate in an aqueous solution in a batch system.The optimum solution pH for phosphate adsorption by Al/SiO2/Fe3O4 was found to be 4.5. The phosphate adsorption behavior by Al/SiO2/Fe3O4 was in good agreement both with the Langmuir and Freundlich adsorption isotherm, and the maximum adsorption capacity ( m q ) and Gibbs free energy of phosphate was 25.64 mg g–1 and -21.47 kJ mol–1, respectively. A pseudo-second-order model could best describe the adsorption kinetics, and the derived activation energy was 3.52 kJ mol–1. The optimum condition to desorb phosphate from Al/SiO2/Fe3O4 is provided by a solution with 0.05 M NaOH.Magnetic adsorbent is a potential material of water treatment method. The results of this study will be helpful in the development of aluminum modified silica magnetic adsorbents that can be used to remove phosphate in aqueous solution.
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