PMS/Cl^-体系中橙黄Ⅱ脱色的影响因素和机理

为考察橙黄Ⅱ在单过硫酸盐(PMS)/Cl^-体系中的脱色过程和脱色机理,研究了初始pH值、PMS初始浓度、Cl^-初始浓度、反应温度等因素对橙黄Ⅱ在PMS/Cl^-体系中脱色效能的影响,通过自由基猝灭试验和活性氯浓度的检测,确定了不同pH值条件下PMS/Cl^-体系中的主要活性氧化物种。结果表明:橙黄Ⅱ在PMS/Cl^-体系中的脱色受pH值的影响;橙黄Ⅱ在该体系中的脱色过程符合准一级反应动力学方程,增加PMS和Cl^-的初始浓度均能提高橙黄Ⅱ在PMS/Cl^-体系中的脱色率;升高反应温度有利于橙黄Ⅱ的脱色;体系中橙黄Ⅱ脱色过程的主要活性物种随着pH值的变化而不同,在酸性条件下体系中橙黄Ⅱ的脱色主要通过活性氯(主要为HOCl)的氯化作用实现,在碱性条件下体系中橙黄Ⅱ的脱色主要由单线态氧(1O2)的氧化导致。该研究结果可为染料废水的治理提供新思路。

Effects and Mechanism of Decolorization of OrangeⅡin PMS/Cl^- System

In order to clarify the decolorization of OrangeⅡin peroxymonosulfate(PMS)/chloride ions(Cl^-)system,this paper investigates the influences of initial pH,initial PMS concentration,initial chloride ions concentration and reaction temperature on decolorization of OrangeⅡin PMS/Cl^-system and identifies the predominant reactive species in the system under different pH value conditions by using radical-quenching experiments and determining the concentration of reactive chlorine.The results show that the decolorization of OrangeⅡin PMS/Cl^-system is affected by initial pH,and the decolorization process of orangeⅡin the system is in accordance with the pseudo first order reaction kinetics;the decolorization rate of orangeⅡin PMS/Cl^-system could be improved by increasing the initial concentration of PMS and Cl^-;the higher reaction temperature is facilitated to the decolorization of OrangeⅡin this system;the predominant reactive species in the decolorization vary with the pH value.Reactive chlorine(mainly HOCl)is responsible for the decolorization of OrangeⅡvia chlorination at acidic pH.Singlet oxygen(1O2)is the predominant reactive species responsible for the decolorization under alkaline pH condition.The research may provide new idea for dye wastewater treatment.