以熱處理程序將含銅污泥轉化為吸附劑與光催化劑之研究

Abstract

因為銅的易溶出性質，含銅污泥為有害事業廢棄物的一種。在含銅污泥的廢棄與再利用時，安定與穩定化是不可忽視的課題，而熱處理程序是相當重要的銅污泥安定穩定化技術之一。熱處理程序具有將含銅污泥轉化成銅鋁尖晶石的潛力，並藉此降低銅溶出的濃度，以達到安定穩定化之目的。 在材料的特性上，銅鋁尖晶石為近年來受到學界矚目的吸附劑與催化劑之一。本研究的目的即在探討藉熱處理技術資源化含銅污泥，並轉化成銅鋁尖晶石吸附劑與催化劑的可能性。研究中同時應用模擬污泥與實場污泥做為材料，探討尖晶石合成的最佳條件與特性。在尖晶石合成的實驗中，利用X光粉末繞射儀(XRD)鑑定產物晶型，以選擇由模擬污泥與實場污泥合成尖晶石的最佳熱處理條件。在吸附與光催化的能力鑑定上，選用甲基橙作為目標污染物，進行吸附與降解的實驗，並得到最佳的反應條件。 實驗結果顯示，在尖晶石的合成上，對於模擬污泥的最佳溫度及時間為1100℃及2小時；對於實場污泥之最佳溫度及時間為1200℃及8小時。在毒性溶出測試(TCLP)中，經過熱處理技術後的污泥，銅溶出量明顯下降，達到污泥安定穩定化的效果。在吸附與降解甲基橙的實驗上，最佳反應條件為pH 7.5，35℃。在125W水銀燈(波長大於400nm)的照射之下，在三小時內由模擬污泥合成的尖晶石對甲基橙的去除率可達67%，實場污泥所合成之尖晶石亦展現了去除效果，也藉此指出了含銅污泥轉換成吸附劑或可見光催化劑的潛力。

Copper-laden sludge is regarded as a hazardous solid waste. Therefore, stabilizing process for the sludge should be taken before disposal and reuse. Thermal process is one of the methods to stabilize the copper-laden sludge. This method has the potential to transform copper-laden sludge into copper aluminate spinel structure (CuAl2O4) in ceramic products to reduce the leaching concentration of copper. Besides, copper aluminate is also a candidate for adsorbent and photo-catalyst. The aim of this research was to investigate the feasibility of adsorbent and photo-catalyst transformed from copper-laden sludge by thermal treatment. Both the simulated sludge and field sludge were used in this study. X-ray diffraction (XRD) was applied to determine the optimum conditions for the thermal process to transform the sludge into CuAl2O4. The target pollutant was methyl orange (MO), which was used to determine the proper reaction circumstance for adsorption and photo-degradation by CuAl2O4. Results indicated that the optimum temperature and heating time for transforming the simulated sludge and field sludge into CuAl2O4 were 1100 ℃, 2 hours, and 1200 ℃, 8 hours, respectively. From the result of toxicity characteristic leaching procedure (TCLP), the leaching concentration of copper had significant reduce, which indicated the stabilizing ability of the thermal process. In adsorption and photo-catalyst experiment, under the optimal reaction, which were pH 7.5 and 35℃, the spinel synthesized from simulated sludge adsorbed or decomposed methyl orange to 67%, within three hours with a light source of the 125W mercury lamp (wavelength > 400 nm). Spinel synthesized from field sludge showed the MO removing ability also. This study demonstrated the potential that copper-laden sludge could be transformed into adsorbent or visible light photo-catalyst.