以Electro-Fenton程序處理對苯二胺溶液之研究

Electrochemical Destruction of p-Phenylenediamine in Aqueous Solution by Electro-Fenton Methods

張祐書(Yu-Shu Chang)

指導教授 ： 顏溪成

國立臺灣大學/工學院/化學工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.01635

摘要

在廢水處理中以高級氧化程序成效最佳，依據不同的反應機制分類，其中又以Electro-Fenton Process與Photocatalysis Process最為廣泛。本篇論文研究以Electro-Fenton Process為主，陽極為白金線與白金鈦網，且陰極為碳布的系統簡稱AP(T)-CC，首先預備實驗藉由陰極碳布通入氧氣並外加電壓進行電化學反應產生H2O2，接著著重在亞鐵離子之還原反應，而後討論一般Electro-Fenton Process程序。接著討論於陰極碳布不通入氧氣，並純粹靠陽極水解反應提供O2，不同陽極面積大小的影響。最後將鐵片自身氧化反應與Fenton Process作結合，以鐵片作為陽極並提供亞鐵離子，且不需外加即可自我產生電流簡稱AF-CC-Shunt。利用此一系統自發性持續提供電流與不斷生成亞鐵離子，使反應可以持續進行並將有機物分解。
陰極過氧化氫生成實驗主要以氧氣進料流量、施加電流、起始pH值以及反應溫度等變因做探討。得知施加電流與過氧化氫初始生成速率成正比關係，並將電極與整個反應器系統作結合，進一步將過氧化氫濃度隨反應時間增加現象做動力學推導與實驗印證。
陰極亞鐵離子還原實驗，主要以起始pH值以及施加電流等變因探討最佳還原效率的條件。在較低pH值的條件下，可以避免氫氧化鐵與氧化鐵的生成所導致之還原效率不佳。
人造纖維合成以及染髮劑等染料中，對苯二胺的應用相當廣泛，但當其排放至環境中除了對水質造成嚴重污染之外，對於人體的傷害，嚴重可能導致乳癌以及膀胱癌等。故本研究以200 ppm對苯二胺作為降解反應中主要降解物。
在AP-CC-Fe2+實驗系統中選擇pH2.5作為最佳的反應背景條件，針對亞鐵離子濃度與施加電流作為主要探討的部分，最佳Fe2+添加初始濃度為3mM。
進一步討論不同陽極表面積對於降解效果之影響。較大之陽極表面積會混淆並且阻礙Fenton Process ，主要原因在於p-Phenylenediamine 於陽極被電解而主導了整個降解反應.

至於Self Electro-generative Fenton Process(AF-CC-Shunt)的研究則針對溫度對於反應的影響。發現提高溫度可促使Fe2+離子迅速自鐵片氧化並產生較大的電流以提供陰極碳布足夠電子來源以生成過氧化氫。相較於其他系統，其優點為不需要施加電流，亦不需要添加Fenton試劑，只須通入氧氣即可自行反應生成電流、亞鐵離子以及過氧化氫，僅此即可達到相當不錯的降解速率。

關鍵字

高級氧化程序 ； 對苯二胺 ； Electro-Fenton程序 ； 鐵陽極氧化 ； 自生成電流

並列摘要

Advanced oxidation process is the best method for wastewater treatment. According to the different classification of reaction mechanisms, Electro-Fenton process and Photo-catalytic reaction have most widely applications. In this study, the AP-CC represented that the anode was Platinum (Pt) or Platinum Titanium mesh (Ti/Pt) ,and the cathode was carbon cloth which was fed with oxygen. The applied current was set to produce H2O2 at the cathode. When the Fe2+ was added into the solution, the system was called AP(T)-CC-Fe2+ system in this research. Next, without O2 injection to cathode, O2 was produced by electrolysis of water from various size of anode to provide to the cathode. Afterward, the iron (Fe) replaced the Pt as the anode with zero applied current, which is the system named AF-CC-Shunt. Besides, the Fe was oxidized to generate current and Fe2+, and the organics would be decomposed by Fenton process.
The flow rate of oxygen, the initial pH value, the applied current , and the reaction temperature were discussed in the H2O2 formation. The initial formation rate of H2O2 is proportional to the applied current. Moreover, electrode reaction and overall reaction system were combined to make derive kinetic derivation and fit the data of H2O2 formation.
The initial pH value and the applied current were discussed in the Fe2+ reduction to find out the optimal current efficiency. Under pH<3, the formation of Fe(OH)3 and Fe2O3 would be prohibited to increase the efficiency.
Due to its popular applications in hair dye and artificial fiber synthetic industry, p-Phenylenediamine causes the quite serious environmental pollution and destroys the metabolism of human being. The initial pH value of reaction system was 2.5. The initial Fe2+ concentration and the applied current were discussed in AP-CC-Fe2+ system. The optimal concentration of Fe2+ is 3mM.
Higher anodic surface area would interrupt Fenton process due to the domination of p-Phenylenediamine oxidation on the surface of Platinum Titanium mesh. According to the AF-CC-Shunt system in the self electro-generative process, the influences of the temperature on degradation and self-generative current were studied. The degradation efficiency was enhanced, due to higher current generated by rapid oxidation of Fe at higher temperature. Compared with other Electro-Fenton processes, in AF-CC-Shunt system, p-phenylenediamine can be degraded by self electro-generative process without applied current and Fenton reagents.

並列關鍵字

Advanced oxidation process ； p-phenylenediamine ； Electro-Fenton process ； anodic oxidation of iron ； self electro-generative current

參考文獻

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