Degradation of Chlorocarbons Driven by Hydrodynamic Cavitation
Degradation of Chlorocarbons Driven by Hydrodynamic Cavitation
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DOI：
10.1002/ceat.200600288
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发表时间：
2007-05
影响因子：
2.1
通讯作者：
Zhilin Wu;B. Ondruschka;Patrick Bräutigam
中科院分区：
文献类型：
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作者：
Zhilin Wu;B. Ondruschka;Patrick Bräutigam
为了给水力空化降解有机污染物的研究提供一个有效的实验室规模的装置，测定了水力空化降解氯仿和四氯化碳的动力学和水溶液电导率的增加。这些是以前没有的值。在水力空化条件下，氯代烃的降解动力学被发现是伪一级。同时，C-H和C-Cl键断裂，Cl 2，Cl.，释放出的Cl-等离子可增加水溶液的电导率，促进KI的氧化。孔板的上游压力、空化数和溶液温度对降解动力学具有实质性影响。降低的空化数可导致更多的空化事件并增强氯烃的降解和/或KI的氧化。温度的降低通常有利于气穴化学反应。来自四氯化碳和氯仿降解的有机产物已经证明了自由基的形成和重组，CCl 4、C2Cl 4和C2Cl 6由CHCl 3降解产生。CCl 4降解产生CHCl 3和C2Cl 6。水力空化降解氯代烃的化学机理和反应动力学与声空化降解氯代烃的化学机理和反应动力学一致。因此，水力空化技术是去除水中有机污染物的一种很好的选择。
To provide an efficient lab-scale device for the investigation of the degradation of organic pollutants driven by hydrodynamic cavitation, the degradation kinetics of chloroform and carbon tetrachloride and the increase of conductivity in aqueous solutions were measured. These are values which were not previously available. Under hydrodynamic cavitation conditions, the degradation kinetics for chlorocarbons was found to be pseudo first-order. Meanwhile, C-H and C-Cl bonds are broken, and Cl2, Cl., Cl– and other ions released can increase the conductivity and enhance the oxidation of KI in aqueous solutions. The upstream pressures of the orifice plate, the cavitation number, and the solution temperature have substantial effects on the degradation kinetics. A decreased cavitation number can result in more cavitation events and enhances the degradation of chlorocarbons and/or the oxidation of KI. A decrease in temperature is generally favorable to the cavitation chemistry. Organic products from the degradation of carbon tetrachloride and chloroform have demonstrated the formation and recombination of free radicals, e.g., CCl4, C2Cl4, and C2Cl6 are produced from the degradation of CHCl3. CHCl3 and C2Cl6 are produced from the degradation of CCl4. Both the chemical mechanism and the reaction kinetics of the degradation of chlorocarbons induced by hydrodynamic cavitation are consistent with those obtained from the acoustic cavitation. Therefore, the technology of hydrodynamic cavitation should be a good candidate for the removal of organic pollutants from water.