油品在土壤中的运移特性

Migration characteristics of oils in soil

随着中国人口的增长和工农业生产规模的持续扩大,土壤污染问题日益严重,石油类污染物对土壤的污染是当前土壤污染的突出问题。通过模拟野外土壤密度和含水条件,开展了室内土柱实验,分别研究了0^#柴油在含水土壤中毛细上升、下渗及水平运移的特性,为全面了解石油类污染物在土壤中的运移行为,石油泄漏后的污染控制与治理提供依据。研究结果表明:柴油在土柱毛细上升的过程中,运移初期和末期上升高度的平方均与时间呈线性关系;油品泄漏后,污染土壤的主要运移方式是重力下渗,大颗粒土壤条件下,柴油的运移以重力下渗为主要运移方式,而对于小颗粒土壤,毛细作用将显著影响柴油的运移;柴油下渗运移速率明显高于毛细上升的速率;柴油水平运移的初始阶段,运移速率明显高于毛细上升速率,在末期两者运移速率趋于一致,说明分子级别的铺展作用受重力的影响较小。

With the growth of population and the continuous increase of industrial and agricultural production scale in China, the soil pollution has become increasingly severe, and the pollution of petroleum contaminants to the soil is currently one of the most prominent problems of soil pollution. In this paper, the soil column experiment in the laboratory was carried out by simulating field soil density and water conditions, and the capillary rise, infiltration and horizontal migration characteristics of 0^# diesel oil in aqueous soil were studied, so as to understand the migration behavior of petroleum contaminants in soil and provide the basis for the pollution control and treatment after oil leakage. It is indicated that the square of the rising height in the initial and final stages of the migration is in linear relationship with the time in the capillary rise process of the diesel in the soil column. After the oil leakage, the main migration mode of the contaminated soil is gravity infiltration. In the condition of large granular soil, the migration of diesel is mainly in the mode of gravity infiltration,while in the condition of small granular soil, it is significantly affected by the capillary effect. Diesel’s infiltration rate is obviously higher than its capillary rise rate. Diesel’s migration rate is much higher than its capillary rise rate in its initial stage of horizontal migration, while they both tend to be the same in the final stage, indicating that the spreading effect of molecular level is less affected by the gravity.