廢棄活性碳微波再生及其吸附效率之研究

Abstract

在現今工業快速發展下，活性碳已被廣泛地使用在廢污水處理、水再生等流程中，隨著活性碳的使用日益增加，其經費成本與廢棄量亦趨增加。因此，活性碳再生被視為處理流程中降低費用的一個重要項目，相較於傳統的許多活性碳再生方法中，微波再生具有處理時間短、效率更高、花費更低、活性碳重損失更低、能量耗損更小、以及不具二次污染等優點。 本研究目標之廢棄活性碳為金門水處理廠所用之二次再生活性碳，使用微波處理作為活性碳再生方法，操作參數包含微波時間、微波功率、樣品含水量等，探討再生後活性碳之升溫變化、碘值吸附能力等物理及化學性質。分析方法包含使用XRD分析再生活性碳之繞射強度，以SEM觀察再生前後結構改變，以BET探討再生活性碳之孔隙及比表面積，並使用再生活性碳吸附RB19染料以進行再生後之吸附實驗。 金門水廠原廢棄活性碳之碘值為450 mg/gAC，在20分鐘微波時間及微波功率100 W至750 W下，再生的顆粒活性碳(RGAC)之碘值可以到達800 mg/gAC，而粉狀活性碳(PAC)在微波時間10分鐘、微波功率450 W下，再生活性碳(RPAC)可以達到碘值1050 mg/gAC，然而，再生活性碳之碘值在微波功率大於850W下，因活性碳結構之損壞而有顯著下降。使用微波再生廢棄活性碳除了有極佳的再生能力、吸附率約為原廢棄活性碳之兩倍以外，並能有效地降低金門水處理廠之花費，因此，研究結果認為微波再生處理流程具有極佳的潛力作為廢棄活性碳再生之流程。

Activated carbons (AC) have been used widely in the water and wastewater treatment and water reclamation plant. Since the benefit/cost of AC has been considered, the regeneration of AC has played an important role both in the treatment process and the cost reducing. Comparing to traditional regeneration methods, the advantages of microwave radiation process include shorter regeneration time, better efficiency, lower cost, less carbon loss, lower energy consumption, and without secondary pollution and specificity of the adsorbate. The objectives of this study were to regenerate the waste AC, which have been regenerated twice, sampled from water purification plant in Kinmen. The microwave radiation process was used as the regeneration method. Physical and chemical characteristics of regenerated AC were investigated. The diffraction intensity of regenerated AC was determined by XRD, structure changes were observed by SEM, and the specific surface area was analyzed by BET. The adsorption efficiencies of waste and regenerated AC under different operation parameters, such as radiation power, adsorption time, and temperature were investigated by iodine number. The iodine number of waste AC in Kinmen is approximately 450mg/gAC. With 20 mins radiation and power of 100 to 750W, the iodine number of regeneration GAC can all reach more than 800mg/gAC and the regeneration PAC can all reach more than 1050mg/gAC with 10 mins radiation and power of 450W.The iodine number will decrease with power higher than 850W resulted from carbon structure ruined. With using microwave radiation, not only the adsorption efficiency of regeneration AC is two times better than that of original waste AC, but also reducing the AC costs in Kinmenwater purification plant. Therefore, the microwave radiation process hasgreat potential for regeneration of waste AC.