关键词: 臭氧, 土壤, 污染, 修复, 动力学

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