| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 99 === This study investigated the synthesis of activated carbon-zeolite composites (AC-Z composites) by alkaline fusion with NaOH and hydrothermal treatment process, using water treatment sludge, water purification sludge ash, and/or their combinations (referred to as sludge wastes, SW). To prepare the precursors (i.e., silicates and activated carbon) for further synthesis of AC-Z composites, the governing conditions during alkaline fusion/carbonation processes (i.e., mix ratio of SW and the NaOH/SW ratio) were selected based on the specific surface area and the target zeolite species identified of the resultants. The effects of reaction time during hydrothermal and aging processes on the species formation and variation in the target AC-Z composites were studied. Furthermore, the performance of AC-Z composites was evaluated using heavy metals, organic dye (methylene blue), and/or their combinations.
Experimental results showed that, in the preparation of precursors, a 3:7 SW mix ratio (i.e., sewage sludge: water purification ash, by wt %) and a NaOH/SW=1.5 were the optimum operational conditions for alkaline fusion/carbonation process.
It was found that zeolite Na-A, Na-X, Na-P1, hydroxysodalite and their combinations, with the carbon content ranging from 8~13%, were identified in resultant AC-Z composites.
The cation exchange capacities of the AC-Z composites synthesized in this study were found ranging from 348-445meq/100g. The maximum adsorption capacity in single and mixed adsorption tests of lead, copper and methylene blue were found to outperform the commercial zeolites (i.e., zeolite 4A and zeolite 13X). The synthesized AC-Z composites were characterized by combining the hydrophobic and hydrophilic properties, thus showing the excellent adsorption efficiency for both metal ions and organic dye. This suggests the preparation of AC-Z composites by alkaline fusion/carbonation and hydrothermal processes are feasible and various applications of the resultant AC-Z composites are potential.
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