施加电压对铬污染土壤电动修复的影响
Effect of applied voltage on electrokinetic removal of chromium from soils
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摘要: 试验研究了不同电压条件下电动修复去除效率和单位能耗随施加电压的变化关系，探讨了电动修复经济有效的电压范围。试验选用重铬酸钾作为污染物，配制高岭土中Cr(Ⅵ)初始质量分数为100mg/kg和500mg/kg，含水量为50%，试验运行48h，用乙酸控制阴极pH在4～7之间，施加一系列不同直流电压。试验结果表明,随着施加电压升高，去除效率增大，电压升高到1V/cm时，去除效率显著升高，2种试验土壤去除效率分别为76.7%和89.8%；同时随着施加电压增加，电能消耗显著增加，与电压呈现线性递增和幂指数递增关系；综合去除效率和单位能耗2种因素，对于试验所研究的土壤，1～1.5V/cm的电压是较为经济有效的。Abstract: Electrokinetic remediation, variably named as electrochemical soil processing, electromigration, ectrokinetic decontamination or electroreclamation, uses electric currents to extract radionuclides, heavy metals, certain organic compounds, or mixed inorganic species and some organic wastes from soils and slurries. This paper presents the experimental study on the effect of applied voltage on the electrokinetic removal of the chromium from kaolin at laboratory scale. Potassium dichromate was chosen as the pollutant and its initial concentration was 100 mg/kg and 500mg/kg, the moisture content of samples was 50%. The experiments were operated for 48hours and the pH of cathode was controlled at 4～7 with of acetic acid. And a series of voltages were applied. The results indicate that the removal efficiencies increase with the increase of applied voltage, when the voltage is 1V/cm, the efficiencies increase significantly, the efficiency reach up to 76.7% and 89.8% of two studied samples. The electric energy consumptions also increase significantly due to the increase of applied voltage. The experimental data show that 1～1.5V/cm is effective and costly voltage range for the soils studied.
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Key words:
- electrokinetic remediation /
- hexavalent chromium /
- pollution /
- soils
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