Abstract: In order to control organic pollution in soil, ozone remediation of soil samples contaminated by 2,4-D(2,4-dichlorophenoxyl acid) was studied in a simulated soil columns. The effect of several factors such as addition of hydroxyl radical inhibitors, soil particle sizes, amount of O₃ in O₃-O₂ mixed gas and moisture content in soil, on the kinetics of ozone remediation(2,4-D degradation) was investigated. To observe influence of water content on the kinetics, various volume of deionized water was added to the soil samles. The experimental results show that all ozone in gas-liquid phase, hydroxyl radicals in liquid-film and active sites on the surface of soil particles play roles in 2,4-D degradation in soil by ozone. For ozone remediation of moist soil there exist gas phase, liquid phase and solid phase, the contact between gas-liquid-solid phases is very important. The 2,4-D degradation by ozone follows the pseudo-first-order kinetics if reasonable simplification and hypothesis are added, and fitting correlation coefficients are higher than 0.9. A kinetic model of soil remediation proposed depends on soil water content. The experimental data reveal that the pseudo-first-order rate constants are fitted well with quadratic polynomial for the range of water content 0-9.38%(mass).

Key words: ozone, soil, pollution, remediation, kinetics

摘要： 为了控制土壤有机物污染，对负载污染物2，4-D（2，4-二氯苯氧乙酸）的模拟土壤柱进行臭氧化修复研究，通过考察羟基自由基抑制剂的加入、土壤粒径的影响以及混合气体中臭氧产生量的影响，分析了2，4-D污染土 壤的臭氧修复动力学，研究了土壤含水量对动力学的影响。研究结果表明，液膜内羟基自由基、气液相臭氧、 土壤颗粒表面的活性位均对降解2，4-D发挥作用。经过合理简化和假设，推导可知2，4-D降解符合拟一级动 力学，对实验数据采用拟一级动力学进行拟合，相关系数均大于0.9。基于土壤含水量，提出动力学模型。实际的实验数据指出在土壤质量含水量低于9.38%范围内，拟一级动力学速率常数和水分含量之间基本符合二次多项式关系。

关键词: 臭氧, 土壤, 污染, 修复, 动力学