亚铁羟基络合物还原转化水溶性偶氮染料

Reductive transformation of hydrophilic azo dye by ferrous hydroxy complex

偶氮染料是印染工艺中应用最广泛的一类染料,目前染料废水脱色是污水处理难题。亚铁混凝处理染料废水过程中可能存在亚铁的还原作用,本实验制备了比溶解态亚铁更具还原反应活性的亚铁羟基络合物(ferrous hydroxycomplex,FHC),以5种不同类型的水溶性偶氮染料为目标污染物,研究FHC还原水溶性偶氮染料的脱色性能。实验结果表明,FHC对活性艳红X-3B、酸性大红GR和阳离子红X-GRL有较好的还原脱色效果,仅投加含铁89.6 mg/L的FHC,染料脱色率达到90%以上,继续增大FHC投加量可以完全脱色;中性枣红GRL的FHC还原脱色效果较差,需加入313.6 mg/L的FHC才能达到90%以上脱色率;134.4 mg/L的FHC能够将直接耐酸大红4BS完全脱色,但其脱色主要以混凝沉淀为主;溶液pH对FHC的还原性能产生重要影响,FHC还原染料脱色的适宜的pH值范围为4～10。该研究为亲水性染料脱色提供了一种新的技术,也为FHC运用于印染废水脱色提供了理论基础。

Azo dye was one of the most widely used dyes in printing technique,the decolorization of its effluent is a challenge in wastewater treatment.Decolorization process of wastewater by coagulation treatment may include the effect of ferrous iron reduction.In this study,ferrous hydroxy complex（ferrous hydroxy complex,FHC） with higher reduction activity than dissolved ferrous iron was prepared,and reductive transformation of water-soluble azo dyes was investigated by using five different types of hydrophilic azo dyes as target pollutants.The results show that reactive red X-3B,acid red GR,cationic red X-GRL are well decolorizated by FHC reduction,the decolorization rate can reach 90%when adding 89.6 mg/L of the FHC.And the dyes can be completely bleached by increasing the dosage continuously.The decolorization of neutral claret GRL is less effective,needing 313.6 mg/L of the FHC to reach 90% decolorization.134.4 mg/L of FHC can completely bleach direct fast scarlet 4BS,but the bleaching mainly owe to coagulation decoloration.The pH has an important effect on the reduction of FHC with optimum pH value range of 4 to 10.The study provides a new technology to treat hydrophilic dye,and it offers a theoretical basis for the decolorization of printing and dyeing wastewater by FHC.