改性活性炭催化过硫酸盐处理甲基橙废水

Treatment methyl orange with persulfate activated by modified activated carbon

为获得低成本、高效率的偶氮染料废水处理方法,采用改性活性炭催化过硫酸盐(PS)氧化降解甲基橙染料废水。通过单因素实验分别研究改性活性炭、PS及Fe^(2+)浓度对甲基橙降解的影响,降解过程遵循拟一级动力学模型,反应速率常数为0.0757~1.7178 min^(-1)。采用Box-BehnkenDesign响应面研究各因素及其交互作用对甲基橙降解的影响,各因素贡献排序为:催化剂投加量>PS浓度>Fe^(2+)浓度,最佳反应条件:催化剂投加量为0.73 g/L、PS浓度为2.0 mmol/L、Fe^(2+)浓度为1.08 mol/L。对改性活性炭催化PS氧化降解甲基橙染料废水的机理进行探究,电子顺磁共振波谱实验表明降解体系中存在羟基自由基和硫酸根自由基,自由基猝灭实验表明改性活性炭表面的羟基自由基在甲基橙降解过程中起重要作用。

For the low cost and high efficiency treatment of azo dyeing wastewater,modified activated carbon was applied to acti⁃vate persulfate(PS)to degrade methyl orange wastewater.Single⁃factor experiments were performed to investigate the effects of the dosage of modified activated carbon,the concentration of PS and Fe^(2+)on methyl orange degradation.The degradation followed a pseudo⁃first⁃order kinetic model,with the pseudo first⁃order rate constant from 0.0757 to 1.7178 min^(-1).The response surface method based on Box-Behnken Design was simulated,and the effects of various factors and their interactions on the degradation of methyl orange were studied.The factors contributed on the degradation were as follows:the dosage of modified activated carbon>the PS concentration>the Fe^(2+)concentration.The optimum condition was 0.73 g/L modified activated carbon,2.0 mmol/L PS and 1.08 mol/L Fe^(2+).The mechanism of methyl orange degradation was investigated.Hydroxyl and sulfate radicals were identified by electron paramagnetic resonance spectroscopy during methyl orange degradation.The surface⁃adsorbed hydroxyl radicals played important roles by radical scavenging tests.