利用photo-Fenton程序降解乙二胺提昇生物可降解性之研究

Abstract

有機剝膜液是半導體製程中，製造基板的加工程序中所必須使用於清潔半成品表面的藥水，該藥水亦是製程液中主要的有機汙染來源，由於其中含有 10% 的乙二胺，對於污染防治上利用偏酸環境下的化學混凝和活性汙泥處理上效果不佳；單一使用化學氧化程序處理時，分解後配合其他處理，效果較佳，但龐大處理設備及費用，卻讓處理技術應用上怯步；未經處理的廢液排放將造成環境上的潛在威脅。 光降解處理基本應用，係經由紫外光的照射激發三價鐵化合物，生成具有強大破壞力的氫氧自由基，以有效的針對有機物進行降解或礦化，為一項具有發展潛力的處理程序。而生物處理為具經濟競爭潛力的處理技術，缺點為對於處理乙二胺，因其難分解特性。本研究以利用 photo-Fenton 程序提昇乙二胺廢水的生物可降解性。 研究結果顯示，50 mg/L 乙二胺溶液，在 pH 3.0 之條件下，Fe2+ 濃度為 267 mg/L，Fe2+/H2O2 為 0.1-10，反應時間為 1 小時，以 photo-Fenton 程序於分解乙二胺後之平均 TOC 去除率約為 7%；且 photo-Fenton 反應前/後，其 NH3-N、NO2- 及 NO3- 濃度並無明顯變化。 於 Fe2+/H2O2 為 0.75 時，去除 1% 乙二胺所產生的 TOC 約需要 4.625 mg/L 的 H2O2 使用量。COD 去除率亦隨著 Fe2+/H2O2 比值增加而增加，除 H2O2 為 200 mg/L 時，COD 去除率呈現下降趨勢，顯示過多之 H2O2 添加可能產生競爭效應。且其 BOD5/COD 比值平均約大於 0.7 以上，顯示 photo-Fenton 可有效提昇乙二胺的生物可降解性。

In the semiconductor substrate process, stripping liquids use for washing unfinished surface. Ethylenediamine (C2H4N2) about 10% in the organic stripping liquids, is the main organic pollutant source in the wastewater of the industry. The decomposition by traditional acid process or physical oxidation and biological disposal are undesirable. This incomplete treatment of the wastewater will impact environment. The photo-degradation process i.e. a higher oxidative treatment, results in the rapid degradation of the target compound compared to other methods. It has been reported that hydroxyl radicals with great destruction power upon excitation of Fe (III) aqua complexes and UV irradiation were useful for the degradation and mineralization of complicated compound. Therefore, photochemical oxidation using Fenton’s reagent and UV irradiation has been considered as a promising technology for the treatment of organic stripping liquids, but higher running cost, and electrical energy demand. Biological treatment is still regarded for general common and economical way treatment of contaminants wastewater. The activate sludge process have demonstrated potentials to fundamentally advance the technology and practice of wastewater treatment. However, they have limitation in the degradation of recalcitrant substance such as the organic stripping liquids. The results show, 50 mg/L Ethylenediamine solution, under the conditions at pH 3.0, Fe2+ concentration of 267 mg/L, Fe2+/H2O2 0.1 to 10, the reaction time is 1 hour to photo-Fenton process in the decomposition of Ethylenediamine The average TOC removal after about 7%; before and after photo-Fenton reaction, the NH3-N, NO2- and NO3- concentration did not change significantly. In Fe2+/H2O2 is 0.75, the removal of 1% of the TOC produced by Ethylenediamine takes about 4.625 mg/L of H2O2 consumption. COD removal rate along with Fe2+/H2O2 ratio increases, in addition to H2O2 was 200mg/L, COD removal rate decreased, much of H2O2 showed possible competition effects added. And its average BOD5/COD ratio greater than 0.7, indicating photo-Fenton process can effectively enhance the biodegradability of Ethylenediamine.