以二氧化鈦/單壁奈米碳管複合材料修飾玻璃碳電極進行COD之伏安法分析

Using the TiO2/SWCNTs composite modified GCE to analyze COD by voltammetry method

黃韻寧(Yun-Ning Huang)

指導教授 ： 秦靜如

國立中央大學/工學院/環境工程研究所/碩士(2015年)

摘要

化學需氧量(COD)為水體有機污染程度的控制與監測的水質項目之一，然而現有的分析技術存在有諸多不足之處，例如對於部分生物可分解的含氮有機物無法被完全氧化，分析方法也不適用於分析揮發性物質等。本研究以溶膠凝膠法製備TiO2/SWCNTs複合材料，以滴附的方法修飾複合材料於玻璃碳電極表面，接著以修飾電極進行線性掃描伏安方法探討得到的氧化峰電流反應訊號與COD濃度之間的相關性:標準品(KHP)受到擴散控制，分為兩區段線性關係，分別為10 ~ 100 mg/L區間和150 ~ 500 mg/L區間。葡萄糖受到吸附控制，在10 ~ 100 mg/L區間有較好的線性關係。草酸於電位－0.7 V處的反應可能非單純為擴散或吸附控制影響，而在0.3 V處的反應受吸附控制的影響較顯著。氫氧化四甲銨(TMAH)和單乙醇胺(MEA)皆受到吸附控制，氧化峰電流訊號值與COD濃度之間都呈現負相關。光電廠放流水將個別添加不同COD濃度的TMAH和MEA，濃度與氧化峰電流訊號值皆呈現正相關。淨水廠放流水連續三天分析結果，發現標準分析方法(CODCr)與LSV電化學分析法確實有類似的趨勢。

關鍵字

化學需氧量 ； 廢水 ； 線性掃描伏安法

並列摘要

Chemical oxygen demand (COD) indicates the degree of water pollution by organic compounds and is usually monitored. There are still several problems in the analysis of COD. For example, COD may be underestimated because some nitrogenous organic compounds cannot be oxidized by K2CrO7 or when the organic pollutants are volatile. Analysis of COD via voltammetry using TiO2/SWCNT modified glassy carbon electrode is developed in this work. COD standard (potassium hydrogen phthalate, KHP), modeled COD samples (i.e., glucose, TMAH, MEA and oxalic acid), and wastewater from the water treatment plant are used to investigate the response of the oxidation peak currents to the concentration of COD. It was found that the oxidation peak current had linear relationship to the concentration of COD and such relationship was dependent on the concentration. That is, the linearity were different in 10~100 mg/L and 150 ~ 500 mg/L. For glucose, such relationship was only good when the COD concentration was lower than 100 mg/L. Because the oxidations of TMAH and MEA are adsorption-controlled, the oxidation peak current decreased with increasing TMAH or MEA concentration. However, when TMAH and MEA were added into the TFT-LCD wastewater, the oxidation peak current increased with increasing TMAH or MEA concentration. Voltammetry of wastewater from water treatment plant showed similar results to standard COD analysis method, which suggests that analysis of COD via voltammetry using TiO2/SWCNT modified GCE electrode is a promising technique.

並列關鍵字

chemical oxygen demand ； wastewater ； linear sweep voltammetry

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