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|Title: ||金屬絡合染料製程廢水之螯合金屬特性 : 由螯合鐵量推估廢水中螯合官能基之去除率與處理方法探討|
|Other Titles: ||Metal-chelating character of wastewater generated from metal-complex dye manufacturing processes : using chelated iron concentration to evaluate the removal efficiency of chelating functional group and treatment options|
|Authors: ||張立瑋;Chang, Li-Wei|
|Keywords: ||金屬絡合染料製程廢水;混凝;螯合;高級氧化法;勻相類Fenton法;wastewater generated from metal-complex dye manufacturing processes;Coagulation;AOP;chelate;homogeneous Fenton-like|
|Issue Date: ||2013-04-13 12:04:27 (UTC+8)|
本研究之處理方式為利用類似於Homogeneous Fenton-like，為亞鐵離子與廢水中螯合金屬之官能基螯合，亞鐵離子能因被螯合而呈溶解態，均勻地分布於廢水中，並能於中性時反應。因此實驗進行於pH7，並與進行於pH3比較。實驗結果為過氧化氫於pH3與pH7下，其隨時間之消耗量相同，但有機物與色度去除率於pH3時較佳 ，而於pH7時也能夠去除少部分之有機物(pH3之TOC去除率約20%，pH7約為5%；色度於pH3時去除率約70%，pH7時去除率約10%)。於pH7時，未被螯合之亞鐵離子逐漸氧化成三價鐵離子，一部分與過氧化氫形成錯合物 (Fe2O3．nH2O)沉澱，一部分則與氫氧根離子結合，形成氫氧化鐵沉澱，則無法再進入Fenton反應之循環中。因此要使用Homogeneous Fenton-like之方法處理時，應考慮能螯合亞鐵離子的量，使較多之亞鐵離子被螯合後，則不受到pH值之影響。
In this study, Dye manufacturing processes wastewater (DMPW) is the effluent generated from synthesizing process of dyes, consisting of intermediated compounds, monomer structure, and dyes molecules.
Coagulation is found to be an inefficient process for removing organic matters. Color of treated water is increased with the decreasing coagulation pH. Measured dissolved iron after coagulation allowed one to evaluate the content of functional groups of organics which can chelate iron from coagulant. Organic removal efficiency is also not very well when pre-precipitated ferric hydroxide was used as adsorbent. It is concluded that DMPW contains hydrophilic functional groups as the result that coagulation is not able to remove the most of the organic matters.
One feature of DMPW is its metal-chelating ability. The C/chelated-Fe3+ molar ratio is used to explore the destruction of chelating functional groups after various treatment processes. The C/chelated-Fe3+ molar ratios of raw DMPW, biologically- treated DMPW, and thermo-persulfate treated DMPW are 15, 29, and 13, respectively. Since chelating functional groups and TOC were reduced after biological treatment, biological treatment process can be employed as a pretreatment process to improve degradation efficiency of DMPW.
In this study, the chelating characteristic of DMPW was exploited with Homogeneous Fenton-like process being tested. The potential of chelating functional groups to enhance oxidation efficient in the Fe(III)/H2O2 system under neutral pH condition was compared with the same process at pH 3. Our results show that the trend of residual hydrogen peroxide concentration in neutral and acidic pHs were the same during a 3-hr reaction. A higher degree of organic matters and colour removal were observed at pH3. The removal efficiencies of TOC are 20% and 5% under pH 3 and pH 7 conditions, respectively, while the removal efficiencies of color are 70% and 10%, respectively. Under pH 7 condition, unchelated ferrous ions are oxidized to ferric ions gradually, and ferric ions form complexes (Fe2O3．nH2O) and precipitate as ferric hydroxide. The precipitated ferric ions could not be used efficiently in Fenton cycle.
|Appears in Collections:||[水資源及環境工程學系暨研究所] 學位論文|
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