| 摘要: | 本研究嘗試以淨水場及污水廠產出之水處理污泥為處理對象，先利用鹼熔程序（alkaline fusion process）碳化並活化污泥中之有機碳及矽、鋁組成，再以水熱合成法（hydrothermal reaction）將轉換形成活性碳－沸石複合吸附材料（AC-Z）。過程中將篩選較佳的污泥及與鹼活化劑之混合比例，建立以水處理污泥為原料製備前驅物（precursor）條件，及探討水熱反應與陳化過程（aging process）之操作變數對複合吸附材料之合成及物種晶相之變化，以不同分析及鑑定方法，找出最佳吸附性能之活性碳－沸石複合吸附材料及其合成條件，並進行重金屬及有機染料之吸附試驗。研究結果顯示，利用水處理污泥以鹼熔法及水熱法合成之活性碳複合材料，於下水污泥和淨水污泥灰混合比例分別為30% 及70% 與鹼活化劑（NaOH）添加1.5倍（w/w）為最佳前驅物製備之條件，其具有最佳的碳化及活化結果；在改變不同的水熱條件下，本研究合成之沸石物種包括A型沸石、X型沸石、P型沸石及水合方鈉石，而複合吸附材料之碳含量為8~13%，且陽離子交換容量之範圍為348~445meq/100g。吸附能力之試驗以重金屬鉛、銅及有機染料亞甲基藍做為標的污染物，其最大吸附量分別為2.17、1.64和0.18mmole/g，在混合系統之吸附試驗中，與市售分子篩相較下對於有機污染物更具去除效果，顯示此活性碳－沸石複合吸附材料具有優良的吸附效能，吸附結果皆優於市售沸石分子篩。本研究結合活性碳及沸石兩種吸附材料於一體，確實提升吸附劑之吸附性能，且在複合材料中同時具備活性碳及沸石之疏水性及親水性表面性質，同時有效解決兩種材料之結合問題同時也綜合兩者之優點，故藉以水處理污泥合成活性碳－沸石複合吸附材料深具資材化再利用之潛力及價值。 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. |
