玫瑰紅染料廢水利用Fenton及photo-Fenton程序脫色處理之研究

Decolorization of RhodamineDyeing Wastewater by Fenton and Photo-Fenton Processes

玫瑰紅是一種具有毒性之化學物質，若未經處理排放於環境中將可能造成對人體健康的傷害，因此，本研究利用Fenton及photo-Fenton程序針對玫瑰紅染料廢水進行脫色反應，並探討不同Fe2+及H2O2加入量、pH及反應溫度對於脫色效果之影響。實驗初始之染料濃度為20 mg/L，pH值為3-7，反應溫度為15-50oC，H2O2加入量為0-90 mg/L，Fe2+加入量為0-12 mg/L，反應中並針對pH及ORP（oxidation reduction potential）進行量測，並分別於不同時間點進行取樣，分析玫瑰紅染料之吸光度並換算為濃度與去除率。實驗結果發現，水樣之初始pH越低，玫瑰紅脫色效率越佳，在pH 3之條件下最佳可達98.7%，而反應溫度之高低對於脫色效率之影響並不明顯，反應溫度在15~50oC間，脫色效率介於71.8%-83.0%，同時以30oC時具有最佳之處理效果。若在初始pH 5.5之條件下，當H2O2為30 mg/L，Fe2+量為0、4、8、12 mg/L時，染料之脫色率分別為4.8%、73.2%、79.3%及 67.4%，顯示較高之Fe2+加入量可提升脫色效果，但Fe2+ 12 mg/L的條件下染料脫色率反而降低；H2O2 90 mg/L時，玫瑰紅在不同Fe2+加入量之脫色率分別為4.2%、76.2%、71.5%及69.0%，與H2O2 30 mg/L之結果相似，顯示H2O2的過量增加並無法提升染料之脫色率。依據脫色反應所呈現之趨勢比較Fenton及photo-Fenton程序分解玫瑰紅之效率發現，UV光和Fenton試劑結合時所產生之協和效應確實可以提升處理效果，但在較高濃度之Fenton試劑加入條件下，協和效應即不顯著。

Rhodamine Bis a well-known toxic chemicals used in dyeing industries. If the Rhodamine Bcontainedwastewater is un-treated and passed through to the environment, it will cause the harmful effect to the human beings. Therefore, this study carried out the Fenton and photo-Fenton processes in the decolorization of Rhodamine B wastewater and investigated the effect of Fe2+, H2O2dosages, pH and temperatures on the efficiency of Rhodamine B decolorization. Experiments were designed at 20 mg/L of Rhodamine B, pH 3-7, reaction temperatures of 15-50oC, H2O2of 0 –90 mg/L and Fe2+of 0 –12 mg/L; during the reaction, pH and ORP (oxidation reduction potential) were monitoring. Experimental results indicated that lower pH levelsareprofitable tothe enhancement of Rhodamine B decolorization. At pH 3, the maximum decolorization efficiency was as high as 98.7%. Effect of reaction temperatures on the decolorization was insignificant, where the decolorization efficiencies were ranging from 71.8%－83.0% at temperatures of 15~50oC. At pH 5.5, it was found that the decolorization of Rhodamine B were 4.8%, 73.2%, 79.3 and 67.4%, respectively, while 30 mg/L of H2O2and 0, 4, 8 and 12 mg/L of Fe2+were dosing into the solution. Since the H2O2dosage was increased to 90 mg/L, decolorization of Rhodamine B at different Fe2+dosages were 4.2%, 76.2%, 71.5% and 69.0%, which indicated that additional H2O2and Fe2+dosages were worthless for the photo-Fenton decolorization system. Comparing the results of Rhodamine B decolorization by Fenton and photo-Fenton process, the synergetic effect by UV and Fenton reagent was useful to enhance the decolorization efficiency; however, thissynergetic effectwas insignificant at higher Fenton’s reagent dosages.