Degradation kinetics and mechanism of trace nitrobenzene by granular activated carbon enhanced microwave/hydrogen peroxide system.
Degradation kinetics and mechanism of trace nitrobenzene by granular activated carbon enhanced microwave/hydrogen peroxide system.
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DOI：
10.1016/s1001-0742(12)60183-1
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发表时间：
2013-07
影响因子：
6.9
通讯作者：
Dina Tan;H. Zeng;Jie Liu;Xiaozhang Yu;Yanpeng Liang;Lanjing Lu
中科院分区：
文献类型：
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作者：
Dina Tan;H. Zeng;Jie Liu;Xiaozhang Yu;Yanpeng Liang;Lanjing Lu
研究了颗粒活性炭（GAC）增强微波（MW）/过氧化氢（H2O2）系统降解痕量硝基苯（NB）的动力学。考察了pH、NB初始浓度和叔丁醇对去除效率的影响。结果发现，反应速率与 MW/GAC/H2O2 过程中的一级反应动力学非常吻合。而且，GAC大大提高了水中NB的降解率。在给定条件下（MW功率300 W、H2O2用量10 mg/L、pH 6.85、温度（60±5）℃），添加4 g/L GAC时，NB的降解率为0.05214 min−1。一般来说，碱性pH值更有利于NB的降解；然而，在测试的pH值范围4.0-12.0内，最适pH为8.0。当H2O2投加量为10 mg/L、GAC投加量为4 g/L时,随着NB初始浓度的增加,NB的去除率降低,表明较低的初始浓度有利于NB的降解。这些结果表明MW/GAC/H2O2 工艺对于水中痕量NB 降解是有效的。气相色谱-质谱分析表明羟基自由基加成反应和脱氢反应增强了NB的降解。
The kinetics of the degradation of trace nitrobenzene (NB) by a granular activated carbon (GAC) enhanced microwave (MW)/hydrogen peroxide (H2O2) system was studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiency were examined. It was found that the reaction rate fits well to first-order reaction kinetics in the MW/GAC/H2O2process. Moreover, GAC greatly enhanced the degradation rate of NB in water. Under a given condition (MW power 300 W, H2O2dosage 10 mg/L, pH 6.85 and temperature (60 ± 5)°C), the degradation rate of NB was 0.05214 min−1when 4 g/L GAC was added. In general, alkaline pH was better for NB degradation; however, the optimum pH was 8.0 in the tested pH value range of 4.0–12.0. At H2O2dosage of 10 mg/L and GAC dosage of 4 g/L, the removal of NB was decreased with increasing initial concentrations of NB, indicating that a low initial concentration was beneficial for the degradation of NB. These results indicated that the MW/GAC/H2O2process was effective for trace NB degradation in water. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction and dehydrogenation reaction enhanced NB degradation.