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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/3402

    Title: 以序列萃取探討集塵灰之重金屬與戴奧辛溶出特性;Leaching Characteristics of Heavy Metals and Dioxin from Different Fly Ashes Using Sequential Extraction Procedure
    Authors: 許桂秋;Kuei-Chiu Hsu
    Contributors: 環境工程研究所碩士在職專班
    Keywords: 戴奧辛;重金屬;集塵灰;序列萃取;heavy metals;dioxin;sequential extraction procedure;fly ashes
    Date: 2008-07-05
    Issue Date: 2009-09-21 12:15:38 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 焚化過程中所產生之集塵灰已列為毒性有害事業廢棄物,本研究以序列萃取、王水消化法及毒性特性溶出程序等溶出方法,探討台灣地區不同煉鋼業別與一般都市固體廢棄物焚化爐(MWI)所產生之集塵灰基本化學鍵結型態與重金屬含量分佈,藉由不同溶出方法探討集塵灰之重金屬溶出潛勢與對環境可能造成之影響。本研究並以序列萃取各階段之殘渣嘗試探討不同酸液試劑對於集塵灰樣品中戴奧辛之總毒性當量濃度的差異及影響因子。 研究結果顯示集塵灰樣品之基本鍵結與溶出特性皆有所差異,視其進料性質、煉鋼業別、煉鋼爐型式、燃燒操作條件等而略有不同。金屬鎘(Cd)主要在水溶解態、離子交換態及碳酸鹽鍵結態等前三階段溶出(A廠:93.6%,B廠:43.1%,C廠:70.8%,D廠:66.5%),移動性很高,集塵灰後續處理時應特別注意。鉛(Pb)主要溶出之鍵結型態隨灰樣之基本特性不同而有所差異。重金屬TCLP溶出試驗結果,A、B及C廠集塵灰鎘的溶出濃度分別為:41.0、6.84及23.7 mg/L,均超出法規標準;所有四個廠灰樣中鉛的溶出濃度分別為:165、83.2、7.92、9.83 mg/L亦皆超出法規標準。序列萃取殘渣戴奧辛測試結果,由17種急毒性PCDD/Fs的分佈發現,原始集塵灰與經過水溶解態、離子交換態、碳酸鹽鍵結態、非晶質鐵錳氧化鍵結態及晶質鐵氧化鍵結等五階段萃取之殘渣在分佈上並無太大變化,且低於法規管制值(1.0 ng I-TEQ/g),直到第六階(硫化物鍵結態)萃取後之殘留物檢測出最高濃度之戴奧辛(B廠之2.450 ng I-TEQ/g與C廠之2.424 ng I-TEQ/g),可見於第六階硫化物鍵結態所使用的強氧化劑與強酸,具有足以將PCDD/Fs大量溶出之能力。 The fly ashes generated from incineration and metallurgical processes have been classified as a hazardous waste. In this study, sequential extraction procedure, TCLP and aqua regia extraction were used to explore chemical bondings and heavy metals in fly ashes generated from different steel industries and municipal waste incinerators (MWI). The potential impact of heavy metals leached in different leaching processes on the environment was investigated. In addition, the effect of acidic agents on total TEQ of dioxin in the collected ash samples was investigated by analysis of PCDD/F contents in residues collected from each fraction of sequential extraction. The results indicate that different chemical bondings and leaching characteristics of collected ash samples were observed and relied on steel-making materials, types of steel industries, types of steel-making furnaces, and operating parameters. Cadmium was mainly leached out from the first three steps (water-soluble, ion-exchangeable, and hydroxides and carbonates fractions) (Plant A: 93.6%, Plant B: 43.1%, Plant C: 70.8%, Plant D: 66.5%) and should be noticed during treatment due to its high mobility. The bonding structure of leached lead was performed differently based on the basic characteristics of ash samples. The results of heavy metals obtained from TCLP showed that the leached cadmium concentrations of collected ashes were 41.0, 6.84 and 23.7 mg/L, respectively, for Plant A, B, and C. These concentrations all exceeded the regulated standard. The leached lead concentrations for Plants A, B, C, and D were, respectively, 165, 83.2, 7.92, 9.83 mg/L, which were all over the regulated standard as well. The distributions of 17 toxic PCDD/Fs extracted from residue using sequential extraction procedure were found no difference in first five different extraction fractions (water-soluble, ion-exchangeable, hydroxides and carbonates, amorphous Fe-Mn oxides and crystal Fe oxides), and their concentrations were all below the regulated standard (1.0 ng I-TEQ/g). The highest concentrations of dioxin in the residue were found at the 6th extraction step(sulfide fraction)and this demonstrated the sufficient ability to leach a large amount of PCDD/Fs by using strong oxidants and acids at the sulfide fraction.
    Appears in Collections:[環境工程研究所碩士在職專班] 博碩士論文

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