| Summary: | 碩士 === 國立交通大學 === 工學院永續環境科技學程 === 104 === This study investigated the surface properties and NH4+ adsorption characteristics of the phosphated titanium-zirconium oxide solid acid prepared by an ionic-liquid assisted hydrothermal method. In addition, the correlation between the adsorption capability and the surface properties of the adsorbent was elucidated. Adsorption isotherm and kinetic study were carried out from a series of batch tests. Moreover, the influences including adsorbent dosage, pH values, and temperatures on the adsorption capability were examined. The results showed that the aggregated particles had a size ranged between 400-500 nm with the specific surface area of 247±20m2/g. The cation exchange capacity (CEC) was 250±20meq/100g, and the pH at zero-point-of-charge (pHzpc) was 3.3±0.2. Dispersion of the adsorbent in water decreased the pH to 4.4±0.5, indicating acidity and cationic exchanging ability of the phosphated titanium-zirconium oxide. The adsorption equilibrium time was 30 minutes and the adsorption kinetic data can be well fitted by a pseudo-second-order model. The Freundlich model fits the adsorption isotherm and the adsorption was an exothermic process with H0= -5.76 kJ/mol. The optimal adsorbent dosage was 70g/L, and the adsorption amount increased with the pH values till pH= 6.25. These results reveal that the ammonia ions are removed in terms of electrostatic attraction and cation ion exchange on the solid-acid-based adsorbent.
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