利用零價鋁金屬去除過氯酸鹽之研究 = Removal of Perchl...
余佳靜

 

  • 利用零價鋁金屬去除過氯酸鹽之研究 = Removal of Perchlorate by Zero-Valent Aluminum in Aqueous Solutions
  • 紀錄類型: 書目-語言資料,印刷品 : 單行本
    並列題名: Removal of Perchlorate by Zero-Valent Aluminum in Aqueous Solutions
    作者: 余佳靜,
    其他團體作者: 國立高雄大學
    出版地: [高雄市]
    出版者: 撰者;
    出版年: 2008[民97]
    面頁冊數: 114面圖,表 : 30公分;
    標題: 零價鋁
    標題: Adsorption
    電子資源: http://handle.ncl.edu.tw/11296/ndltd/04195104229632310285
    附註: 指導教授:連興隆
    附註: 參考書目:面86-96
    附註: 附錄:1.反應物與產物之檢量線;2.初步測試結果
    摘要註: 本論文研究目的係利用酸洗之零價鋁金屬去除水中過氯酸鹽(ClO4-),以探討其去除成效及去除機制。過氯酸鹽是難分解之無機性含氯污染物,其還原電位極高(+ 1.287 V),是一個很強的氧化劑。就反應熱力學而言,理論上過氯酸鹽應該很容易被還原降解成氯離子,然而由於反應動力學之限制,文獻指出傳統零價金屬還原技術(如零價鐵),對過氯酸鹽的還原降解速率非常慢。本研究利用酸洗之零價鋁金屬,探討其還原降解或吸附去除過氯酸鹽之可行性。研究發現,酸洗之零價鋁金屬在 24小時內,可去除10 mg/L過氯酸鹽達 80~90%,遠高於零價鐵金屬之去除效率。理論上,過氯酸鹽若被還原降解後,氯離子產量應相對增加,然而實驗發現,氯離子生成並不顯著。利用脫附實驗,加入0.5 mL 硫酸鎂(0.1 N)做為脫附劑,可把金屬表面吸附之過氯酸鹽脫附至水溶液中,其脫附量達過氯酸鹽初始濃度之85%,顯示零價鋁金屬去除過氯酸鹽機制為吸附作用。進一步分析發現,吸附效果來自於零價鋁金屬氧化後之產物-氫氧化鋁(Bayerite)。以氫氧化鋁當做吸附劑,在酸性條件下(pH = 4.5),10分鐘之內可去除10 mg/L過氯酸鹽達 99%以上。由界達電位實驗得知,氫氧化鋁之等電位點 (pHzpc)為 8.02,當pH小於 8.02時,表面所帶電荷為正電荷,過氯酸鹽屬於陰離子,可有助於提升過氯酸鹽之吸附量,當pH大於 8.02時,表面所帶的負電荷比較多,吸附過氯酸鹽效果就大幅降低。等溫吸附曲線數據則以Langmuir 方程式分析,當pH值為 4.5時,氫氧化鋁吸附過氯酸鹽飽和吸附量為 3.37 mg/g。 The objective of this study was to investigate the feasibility of perchlorate removal by zero-valent aluminum in aqueous solutions. Perchlorate is a highly stable anion that has been identified as a commonplace environmental contaminant. Perchlorate salts are typically used as energetics boosters or solid oxidants in rocket and missile propellants; consequently, the source of pollution is tied directly to all too necessary and space industries. Preliminary studies have indicated that approximately 80~90% of perchlorate are rapidly removed with in a 24 hour period. However, no reduction product, chloride, was found. The disappearance of chloride may be attributed to the chloride adsorption taking place at the aluminum oxide surface. This study indicated that the perchlorate removal is attributed to the surface adsorption rather than the chemical reduction. The adsorbed perchlorate ions were desorbed effectively by a 1.0 N MgSO4 solution. The effective composition for the perchlorate adsorption is confirmed as aluminum hydroxide (Bayerite), which is a product of the aluminum corrosion. The perchlorate adsorption by aluminum hydroxide is dependent on the solution pH. According to the zeta potential, the aluminum oxide has the point of zero charge (pHzpc) of 8.02. A maximum adsorption capacity of 3.37 mg/g were determined for perchlorate removal.
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310001727570 博碩士論文區(二樓) 不外借資料 學位論文 008M/0019 541606 8025 2008 一般使用(Normal) 在架 0
310001727588 博碩士論文區(二樓) 不外借資料 學位論文 008M/0019 541606 8025 2008 c.2 一般使用(Normal) 在架 0
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