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標題: | 磁性吸附劑之合成及其在水中銅及銦污染物處理上之應用 Synthesis of magnetic polymer adsorbent and its application for the removal of cupric and indium pollutants from water |
作者: | Jyi-Yeong Tseng 曾吉永 |
指導教授: | 張慶源 |
關鍵字: | 磁性高分子聚合物,高梯度磁分離,錯合劑,吸附,脫附,銅,銦, Micro-size magnetic polymer,magnetic adsorbent,desorbent,desorption,metal chelating ligand, |
出版年 : | 2009 |
學位: | 博士 |
摘要: | 本研究探討磁性高分子吸附劑的合成,及其應用於水中銅及銦污染物的去除。其後利用高梯度磁場分離回收磁性高分子吸附劑。
研究中利用化學共沈澱法製造超順磁性Fe3O4的凝膠(M),並分析此超順磁性奈米磁鐵礦的特性。取此凝膠加入醋酸乙烯酯(vinyl acetate)、二乙烯苯(divinyl benzene)、及其它有機物質(聚乙烯醇(ployvinyl alcohol, PVA)、甲烯藍(methylene blue)、過氧化二甲苯(benzyl peroxide)) 等反應物,再利用懸浮聚合法進行化學合成以製造出含有Fe3O4的磁性有機聚合物顆粒 (M-PVAC)。然後,再進行醇化(alcoholysis)、環氧烷基活化(epoxide activation)、及偶聯(coupling)亞胺二醋酸(iminodiacetic acid, IDA)螯合劑等顆粒表面的化學改質以合成M-PVAC-IDA,及其表徵分析。 以合成之M-PVAC-IDA針對銅及銦離子進行吸附及脫附實驗。藉由銅及銦離子吸、脫附實驗之數據可建立等溫吸、脫附線結果顯示銅離子於pH值等於1, 2, 4.5之吸附實驗,在pH值為4.5時利於吸附且適合以Freundlich模式描述平衡關係。而銦之吸附在pH值等於2, 3時均利於吸附,在pH值為3時適合Freundlich模式,在pH值為2時則以Langmuir較適用。研究中並假性一階動態模式和假性二階動態模式分別用來模擬動態吸附與脫附行為,結果顯示M-PVAC-IDA吸附高濃度的銅離子以假性一階動態模式較適合。藉由內部質量傳送機制(表面擴散)及外部質量傳送機制(膜擴散)之探討,發現M-PVAC-IDA吸附銅和銦離子以外部質量傳送機制為速率決定步驟。另外,根據結晶場理論之探討,可發現M-PVAC-IDA吸附銅離子需要四個配位數形成一平面結構。經由表面錯合平衡常數 和 的計算,可得M-PVAC-IDA吸附銅銦之表面錯合平衡常數分別為 2.85, 0.22。探討高梯度磁分離時,實驗之結果可以模式加以適當的模擬。此高梯度磁分離模式可預測有效分離時間及最適流速等操作參數。 This study investigated the synthesis and application of magnetic polymer adsorbent for the removal of cupric and indium ions. Firstly, a novel approach for the preparation of superparamagnetic nanostructured particles was conducted. The superparamagnetic Fe3O4 colloids with a number mean diameter of 8 nm were produced by chemical coprecipitation methods. Through synthetic reactions with vinyl acetate, divinylbenzene, or other organic matters (such as polyvinyl alcohol, methylene blue, benzyl peroxide), magnetic nanoparticles were covered by the organic polymer via the suspension polymerization. Further alcoholysis, epoxide activation and coupling of iminodiacetic acid (IDA) were employed to introduce functional groups on the surface of superparamagnetic particles, without demolishing the magnetite within the particles. Hence, the magnetic polymer adsorbents (denoted as M-PVAC-IDA) were manufactured with the desired chemical properties. Then, the properties and chemical composition of the surface modified particles were analyzed. The adsorptive and desorptive experiments of cupric and indium ions as pollutants in water via the synthesized M-PVAC-IDA were performed. From the experimental result, the corresponding adsorption and desorption isotherms were set up. Freundlich adsorption isotherm and Langmuir adsorption isotherm are introduced to describe the equilibrium behaviors, indicating the former gives the better agreement with the experimental data. Two simple kinetic models, the pseudo-first-order equation and pseudo-second-order equation, are employed to simulate the kinetic behaviors of adsorption and desorption. Because the initial solid-phase concentration of adsorbate may not be zero, the nonlinear functions are employed. For the description of adsorption behavior, both simulated results by the pseudo-first-order and pseudo-second-order kinetic models exhibit good agreements. The mass transfer mechanisms of the adsorption of Cu(II) and In(III) onto M-PVAC-IDA are elucidated using conventional kinetic models (e.g., film, surface and pore diffusion models), respectively. The transfers of Cu(II) and In(III) from the bulk solution into the polymer adsorbents are found to be controlled by external mass transfer mechanism, noting that the film diffusion model offers the better description. Moreover, the mechanism of chelating reaction of carboxylic groups of M-PVAC-IDA with Cu(II) can be well interpreted by the Crystal Field Theory. Thus, the M-PVAC-IDA totally provides four coordination numbers to Cu(II) to form planar structure. Furthermore, the dynamic high gradient magnetic separation behaviors can be be well described by the Watson-Gerber kinetic model of mass balance of magnetic particles. Accordingly, the effective separation time and optimum velocity can be predicted. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/22841 |
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顯示於系所單位: | 環境工程學研究所 |
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