- 學位論文
連續攪拌反應器培養真菌-細菌對偶氮染料脫色之研究
Decolorization of azo dyes by fungal-bacterial cocultures in continuous stirred-tank reactor
摘要
染料廢液的排放在染整業中一直是很嚴重的環保問題，傳統上的處理是以物理及化學法為主，但這些處理方式伴隨許多缺點與二次污染物產生，而以微生物進行色度的去除是對環境最友善的方法。本實驗將Aspergillus niger及Bacillus sp.混合培養後進行固定化，利用此混合固定化菌體進行脫色的反應。反應試料是Reactive red dye HE3B(C.I Reactive red 120)染料以不同濃度加入2L蒸餾水中並添加0.1％fructose及0.7％KH2PO4混合而成，在磁石攪拌及蠕動幫浦循環下進行未滅菌開放式的批次循環與連續攪拌槽反應器（continuous stirred-tank reactor, CSTR）脫色反應，以模擬染整廠廢水的脫色程序。 實驗結果指出，起始染料濃度以50ppm為最佳的添加量，染料濃度越高會影響菌體的生長與分解的效果。在275 mL/min批次循環流動中添加120g菌重，經6h培養脫色率為81.45％，持續運行24hr則可達91.79％的脫色率，增加菌重雖有助於脫色率的增加，但單位菌重脫色的效益降低，故選定120g作為添加菌重的基準，另外通入空氣於反應器中並未對脫色產生明顯的幫助。但當流速提高至950 mL/min，脫色效益可提高到94.08％。120g的菌體在經過96hr持續脫色培養後，脫色率由24小時的94.65％下降為56.96％，但可證明此固定化菌體經過長時間操作，仍可維持50％以上的脫色效果。綜合以上最適化的脫色條件，模擬染整廠作業流程，以CSTR反應槽串聯方式進行大量染料的脫色。實驗結果顯示，6L的50ppm染料在反應時間6小時後(經過3個反應器，每個反應器滯留時間2hr)，其最終的脫色率可達90.74％，證明CSTR操作能快速脫色，確實可以對大量染料廢水進行快速的色度去除。將脫色後的代謝產物進行FTIR以及UV–vis spectral scan的檢測分析，結果顯示，經微生物的吸附及分解後染料的最大的吸光波峰大幅下降且推測其化學結構上並無苯胺類有毒代謝物產生。
並列摘要
The pollution which caused by dyes is always a serious environmental problem in the textile industry. Dyes can be removed from wastewater by chemical and physical methods, but we can still see that some disadvantages appear while certain process was followed. Conversely, bioprocessing seems to be the best choice to decrease the pollution, and to minimize the affection of the environment. In this experimentation, we chose Aspergillus niger and Bacillus sp., to process the dye decolorization after immobilized preparation. We used different concentration of ”Reactive red dye HE3B(C.I Reactive red 120)” in 2 L of water, and added 0.1％ fructose and 0.7％ KH2PO4, under the magnetic stir and peristaltic pump recycling medium to act as non-sterilized, recycle serial process, and continuous flow stirred-tank reactor（CSTR）decolorization in open state. In order to find the optimal options of decolorization, we added 120 g of fungal-bacterial cocultures and got a efficiency of 81.45％ after 6hr and decolorization 91.79% after 24hr. Pumping air in the medium did not provide obviously increasing on decolorization; a suitable beginning dye concentration was at 50ppm; Mentioned about recycling rate, with the rate of 950 mL/min, we had a decolorization up to 94.08% after 24 hours reaction; After 96 hours cell tolerance test, the decolorization decreased from 94.65% of 24 hours reaction to 56.96%, but still, we could confirm this stabilized fungal-bacterial cocultures existing more than 50% decolorization after a long term process. After finding the best options, we follow this information, and expand to a CSTR reactor to exam the decolorization. The result showed that the final decolorization of 6 L medium was 90.74% in a 6-hour period of time (through 3 reactors, 2 hours of space time per reactor), which also confirmed that CSTR operating procedure performed a higher speed of decolorization, and surely can process the color removing fast on mass of textile wasted water. The chemical structure of decolorized residues had been assayed by FTIR. Based on the results, there were no any aromatic amines in the residues. Therefore, the azo bond had been breakdown in the decolorized procedure and did not produce any toxic components. Therefore, CSTR mode could be applied to wastewater treatment of textile industry for dye decolorization.