| 还原-ZPF催化氧化降解2,4-DNT效果及其机制 |
| 摘要点击 3385 全文点击 2070 投稿时间：2010-11-12 修订日期：2011-02-28 |
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| 中文关键词 硝基苯类化合物 α-FeOOH柱撑人造沸石 pH值 地下水修复 2，4-二硝基甲苯 还原-ZPF催化氧化 |
| 英文关键词 nitro aromatic compounds zeotileartificial pillared by α-FeOOH pH value remediation of groundwater 2,4-dinitrotoluene reduction-ZPF catalytic oxidation |
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| 中文摘要 |
| 以实验室制备的α-FeOOH柱撑人造沸石(zeotileartificial pillared by α-FeOOH, ZPF)为催化剂，并利用FTIR与XRD技术进行表征，采用批式实验研究其催化H2O2氧化去除地下水中难降解有机污染物2,4-二硝基甲苯(2,4-DNT)的效能，对比分析不同pH条件下Fe0还原、ZPF催化氧化及还原-ZPF催化氧化3种修复技术对2,4-DNT的去除效果，分析ZPF/H2O2催化氧化作用机制.结果表明，低pH利于2,4-DNT还原，pH=5时，反应120 min后，其还原率为96.6%，分别为pH 7、pH 9时还原率的1.2、2.0倍，最终还原产物为2,4-二硝基甲苯（2,4-DAT）；不同pH时，ZPF/H2O2催化氧化降解2,4-DNT的能力存在如下关系：pH=7> pH=9> pH=5，且反应体系pH值接近α-FeOOH零电点时， 2,4-DNT催化氧化降解效果较好，其降解数据符合拟一级反应动力学模型.还原-催化氧化技术可先将2,4-DNT还原降解为易于催化氧化去除的2,4-DAT.pH=7时，2,4-DNT还原-ZPF催化氧化一级表观动力学常数kobs为0.0027 min-1，2,4-DNT的相对去除率提高为57.4%.反应体系中溶出Fe离子的浓度远小于0.07 mmol/L，作用机制主要为非均相芬顿反应，最终将2,4-DNT矿化降解为CO2和H2O.因此，还原-催化氧化组合技术去除地下水中2,4-DNT效果明显优于单一处理。 |
| 英文摘要 |
| ZPF(zeoliteartificial pillared by α-FeOOH) which prepared in the laboratory and characterized by FTIR and XRD was used as catalyst, and was tested for its activity in catalytic H2O2 of 2,4-DNT, which is persistent and difficult to be degraded in groundwater. The degradation of 2,4-DNT was examined at different pHs in the reduction, catalytic oxidation and combination technology of reduction-catalytic oxidation reaction systems. Moreover, the removal effect of 2,4-DNT was compared by these three approaches and the catalytic oxidation mechanism was analyzed. The results demonstrated that the removal effect of 2,4-DNT reduced to 2,4-DAT was up to 96.6% in 120 min at pH=5, which was 1.2, 2.0 times of the rate at pH 7, pH 9 respectively. The catalytic effect was various at different pHs and more significant when the pH close to the zero point of charge of α-FeOOH. The order of removal effect of 2,4-DNT at different pHs was pH=7> pH=9> pH=5.Compared to single reduction or catalytic oxidation, the removal effect of combination technology was 57.4%, which was evidently improved on the base of 2,4-DNT reduced to 2,4-DAT. The degradation of 2,4-DNT in the presence of ZPF/H2O2 follows a first-order kinetic model and the kobs was 0.0027 min-1. Due to the concentration of dissolved Fe ion was far less than 0.07 mmol/L, the mechanism was heterogeneous Fenton reaction acting on the surface of the catalyst. Therefore the combination technology was superior to the single treatment of reduction or catalytic oxidation. |
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