表面活性剂对陕北石油污染土壤的修复效应研究

Research on remediation effect of surfactant on petroleum contaminated soil in Northern Shaanxi

陕北地区耕地资源匮乏,石油污染加重了耕地短缺,进而威胁粮食安全。因此,在陕北地区,开展土壤石油污染修复的应用技术研究显得尤为重要。本研究采用盆栽试验,模拟不同原油浓度污染的土壤,对比研究不同类型表面活性剂对不同种类石油烃的去除效应,以期筛选出经济效益高、应用潜力大的表面活性剂,为陕北污损土壤修复提供参考依据。结果表明:添加不同类型的表面活性剂,土壤中总石油烃残留量呈鼠李糖酯<吐温-80<天然皂粉<乙氧基化烷基硫酸钠AES,且鼠李糖酯处理下的残留量与其他活性剂之间的差异均达到显著水平(p<0.05),多环芳烃的残留量亦表现出类似的规律;当原油浓度为1 g·kg-1时,添加不同类型表面活性剂修复半年后土壤中总石油烃残留量均小于背景值,但当原油浓度增大至5、10 g·kg-1,其残留量则远高于背景值,将会影响作物的正常生长;鼠李糖酯对石油烃的去除率随石油浓度的增加而不断减小,当原油浓度为1、5、10 g·kg-1时,对总石油烃的去除率最低,分别为73.9%、62.7%和58.2%,约是自然降解率的3.1、2.6、2.4倍;而去除率最高的萘,其去除率分别达到90.4%,88.4%、85.9%。

Cultivated land resources in Northern Shaanxi are deficient, while oil pollution has worsened the shortage of cultivated land, thereby threaten food security. This study used pot experiments to simulate soils polluted by different crude oil concentrations, and compared the removal effects of different types of surfactant on different types of petroleum hydrocarbons in order to screen out surfactant with high economic benefits and great application potential, to provide a reference to repair contaminated soil in northern Shaanxi. The results showed that: When adding different kinds of surfactant, the residual amounts of petroleum hydrocarbons in soil was as follows: rhamnolipid <Tween-80<natural soap powder<AES, and the difference between the removal efficiency of rhamnolipid and the other three kinds of surfactant was significant(P<0.05), the residual amounts of PAHs also showed a similar pattern;When the crude oil concentration was 1 g·kg-1, the residual amounts of total petroleum hydrocarbons was smaller than the soil background value after 6 months. However, when the concentration of crude oil increases to 5 g·kg-1 or 10 g·kg-1, the residual amount were much higher than the soil background value, which will affect the normal growth of crops;The removal rate of petroleum hydrocarbon by rhamnolipid decreased with the increase of oil concentration. When the concentration of crude oil were 1 g·kg-1, 5 g·kg-1, 10 g·kg-1, the removal rate of total petroleum hydrocarbons in soil were the lowest at 73.9%, 62.7%, and 58.2%, which are approximately 3.1, 2.6, and 2.4 times the natural degradation. However, the naphthalenes with the highest removal rates reached 90.4%, 88.4%, and 85.9%, respectively.