紫外光强化Fe(Ⅱ)-EDTA活化过硫酸盐降解直接耐酸大红4BS  

Decolorization Effect of Direct Fast Scarlet 4BS by Fe (Ⅱ)-EDTA Activated Peroxodisulfate under Ultraviolet Light

作　　者：尹汉雄 唐玉朝[1] 黄显怀[1] 薛莉娉[1] 徐满天 胡伟[1] 王涛[1] 

机构地区：[1]安徽建筑大学水污染控制与废水资源化安徽省重点实验室,安徽合肥230601

出　　处：《环境科学研究》2017年第7期1105-1111,共7页Research of Environmental Sciences

基　　金：国家自然科学基金项目(50908001);国家科技重大专项(2014ZX07405-003);安徽省教育厅自然科学重点项目(KJ2015A109)

摘　　要：为探索硫酸根自由基对偶氮染料的降解能力,以直接耐酸大红4BS(下称大红4BS)为模拟污染物,通过UV/Fe(Ⅱ)-EDTA/PDS(PDS为过硫酸钠)体系,探讨了初始c(PDS)、Fe(Ⅱ)/EDTA(摩尔比)、无机盐阴离子等对大红4BS降解的影响.结果表明,大红4BS的脱色率随着初始c(PDS)的增加而增大,当c(PDS)超过15 mmol/L时无显著变化.Fe(Ⅱ)/EDTA比在5∶1时效果最好,5 min时使0.038 0 mmol/L大红4BS的脱色率达到93.6%.反应符合二级动力学模型.HCO_3^-、Cl^-、NO_3^-、SO_4^(2-)等无机盐阴离子表现出明显抑制作用,c(无机盐阴离子)在100 mmol/L条件下,脱色率分别降低66.9%、13.2%、12.1%、9.43%.利用紫外可见光谱,依据其结构与特征吸收的关系,初步推测自由基离子对大红4BS降解的途径:苯环最先遭到破坏,随后偶氮键断裂、萘环开裂.研究显示,UV光可有效强化Fe(Ⅱ)^-EDTA活化过硫酸盐形成SO_4^-·自由基,对偶氮染料具有很好的脱色能力,最佳反应条件[PDS∶Fe(Ⅱ)∶EDTA(摩尔比)为15∶5∶1]下,大红4BS在10 min时脱色率高达98.1%.Wastewater containing azo dyes is difficult to be biodegraded because of its structural stability,which poses a serious threat to the environment. In order to study the degradation of azo dyes by SO_4^-·radicals,degradation of Direct Fast Scarlet 4BS with radicals activated by UV enhanced Fe( II)-EDTA persulfate system was investigated. The effects of initial concentration of PDS,Fe( II) /EDTA and inorganic anions on the degradation of 4BS in UV/Fe( II)-EDTA/PDS system were discussed. The results showed that the 4BS decolorization rate increased with the increasing of PDS concentration,but there was no significant change when PDS was more than 15 mmol /L. At the most optimal Fe( II) /EDTA ratio of 5∶ 1,the 4BS could decolorize 93. 6% within 5 min when the initial concentration was0. 0380 mmol/L. It followed the second-order kinetics model. The inorganic anions such as HCO_3^-,Cl^-,NO_3^-and SO_4^(2-)showed obviously negative effects for the degradation of 4BS when the inorganic anions were 100 mmol/L; decolorization ratio reduced 66. 9%,13. 2%,12. 1% and 9. 43%,respectively. The relationship between structure and characteristic absorption was analyzed by UV-Vis spectroscopy,and we speculated that the 4BS degradation pathway is as follows: Benzene is broken first,then azo bond cleaves and naphthalene ring cracks. In the presence of PDS-Fe( II)-EDTA,the UV radiation could effectively enhance the activation of the persulfate to form SO_4^-·free radicals,which can decolorize Azo dyes. The decolorization ratio of 4BS was up to 98. 1% within 10 min under the optimum reaction conditions[PDS∶ Fe( II) ∶ EDTA = 15 ∶ 5 ∶ 1]in the UV-PDS-Fe( II)-EDTA system. The results suggested that the oxidation method based on SO_4^-· radicals may be a very effective technique to be used in the treatment of dye wastewater or other refractory wastewater.

关 键 词：直接耐酸大红4BS 紫外 活化过硫酸盐 EDTA(乙二胺四乙酸) 螯合Fe(Ⅱ) 

分 类 号：X52[环境科学与工程—环境工程]