二硫化鐵活化過硫酸鹽降解反應性及直接性偶氮型染料之研究

本研究以二硫化鐵(FeS2)作為Persulfate(PS)反應中的催化劑，針對雙偶氮染料Direct Red 23、Direct Blue 15、Reactive Red 120與Reactive Black 5染料脫色效能之比較，並以超聲波(US)與熱輔助PS反應進行。FeS2表面中的S元素可以使反應後生成的Fe3+還原為Fe2+，進而使反應循環，使染料脫色效果更為顯著。研究結果顯示在PS/FeS2反應中加入FeCl3後能使染料脫色效果更佳，從自由基釋出比例得出SO4－˙比例PS/FeS2 (26%)較高(38%)，且在分別加入SDBS、Tri X-100、NaHCO3、MF後以PS/FeS2/FeCl3/US程序能使混合後的染料在反應20分鐘ADMI降至於400以下，反應60分鐘ADMI降至53，遠低於放流水標準；COD去除情形以PS/FeS2程序的去除率為66%，以PS/FeS2/FeCl3程序去除率為80%，若是再加入高溫輔助COD去除率可上升到95%，效果十分顯著。研究結果證實FeS2作為PS反應中的催化劑能有效降解直接性與反應性的雙偶氮染料，且使用超聲波與熱輔助皆能使ADMI與COD降至放流水標準以下；以自由基抑制試驗能夠證實加入FeCl3以利PS/FeS2形成循環，加速對染料脫色的效能。

關鍵字

二硫化鐵；過硫酸鹽；超聲波；偶氮染料

並列摘要

In this study, iron disulfide (FeS2) was used to activate persulfate (PS) reaction to compare the decolorization efficiency of the azo dyes Direct Red 23, Direct Blue 15, Reactive Red 120 and Reactive Black 5. Ultrasound irradiation (US ) and heat were used to assist the activated PS process. The S element on the surface of FeS2 can reduce the Fe3+ to Fe2+, which in turn makes an oxidative reaction cycle for dye degradation more effectively. The research results show that the addition of FeCl3 in the PS/FeS2 reaction can make the dye degradation better. It was evidenced that the ratio of SO4－˙ radicals generated from PS/FeS2/Fe3 (38%) is higher than that of PS/FeS2. When the dye solution contains dying agents, such as SDBS, Tri X-100, NaHCO3, and MF, the PS/FeS2/FeCl3/US enabled to degrade dye to below 400 ADMI in 20 min and further to 53 ADMI within 60 min, which is far lower than the effluent discharging standard for textile and dying industries. As for COD removal, the process of PS/FeS2 and PS/FeS2/FeCl3 achieved 66% and 80%, respectively. When the process PS/FeS2 coupled with heat, up to 95% COD removal was achieved. The findings show that FeS2 activate PS can effectively degrade the direct and reactive azo dyes; specifically the assist of ultrasound and thermal assistance are able to further reduce ADMI and COD to below the effluent standard. Based on the results of free radical identification and the addition of FeCl3, the role of S in the PS/FeS2 act as a mediator to tringle a oxidative cycle that accelerate the degradation of dye.