摘要：

采用紫外光活化过硫酸盐（UV/PS）体系氧化处理偶氮染料甲基橙，考察了甲基橙初始浓度、过硫酸钾投加量、无机阴离子（HCO₃ ^-、Cl^-）、印染助剂对甲基橙脱色效果的影响。结果表明，UV/PS体系能有效去除甲基橙，反应过程符合准一级反应动力学，甲基橙去除速率随初始浓度的增加而降低，过硫酸钾投加量与去除速率呈正相关关系。HCO₃ ^-浓度在0~0.5 mmol/L时抑制甲基橙脱色，0.5~5.0 mmol/L时促进脱色；低浓度的Cl^-轻微促进甲基橙脱色，高浓度有抑制作用。印染助剂柠檬酸钠、十二烷基苯磺酸钠的存在均不利于甲基橙的去除，浓度为5.0 mmol/L时，甲基橙反应速率常数从0.054 6 min^-1分别降低到0.023 0 min^-1、0.035 5 min^-1。自由基猝灭实验表明SO₄ ^·-、HO·是甲基橙去除的主要活性氧化物种。

关键词: 过硫酸盐, 高级氧化过程, 甲基橙, 硫酸根自由基

Abstract:

Azo dye methyl orange was oxidized by ultraviolet activated persulfate（UV/PS） process. The effect of initial concentration，potassium persulfate dosage，inorganic anions（such as bicarbonate and chloridion）and dyeing auxiliaries on the decolorization performance of methyl orange were investigated. Results showed that the UV/PS system could effectively remove methyl orange and the reaction processes followed pseudo-first-order kinetics. The removal rate of methyl orange decreased with increasing initial concentration and was positively correlated with the dosage of potassium persulfate. The presence of bicarbonate ions affected the decolorization of methyl orange and an inhibitory effect at a lower bicarbonate concentration of 0-0.5 mmol/L was observed，whereas promotion phenomenon was found at 0.5-5.0 mmol/L. Low concentration of chloride slightly accelerated the decolorization of methyl orange，while high concentration of chloride exerted inhibition effect. In addition，the presence of dyeing auxiliaries，such as sodium citrate and sodium dodecylbenzene sulfonate（SDBS）inhibited the removal of methyl orange. When the concentrations of sodium citrate and SDBS were both 5.0 mmol/L，the reaction rate constant of methyl orange decreased from 0.054 6 min^-1 to 0.023 0 min^-1 and 0.035 5 min^-1，respectively. Free radical quenching experiment indicated that SO₄ ^·- and HO· were the predominant reactive oxidizing species for the removal of methyl orange.

Key words: persulfate, advanced oxidation processes, methyl orange, sulfate radical

中图分类号: 

• X703.1