【作者】 何小路；

【导师】 施周；

【作者基本信息】 湖南大学 ， 市政工程， 2005， 硕士

【摘要】 由于其致癌性,多氯联苯(PCBs)已经成为环境中一类重要的有机污染物。其物理化学性质稳定,且具有难降解性。由于其疏水性使得多氯联苯往往与受污染的土壤底泥结合紧密,使得对于含PCBs土壤的处理十分困难。 本文对表面活性剂修复PCBs污染土壤的效果进行了研究。当选用阴离子表面活性剂SDS(十二烷基硫酸钠)对污染土壤修复时,10000mg/L的SDS溶液能分别将人工和野外污染土壤中67.8%和54.1%的PCBs洗脱出来。而选用10000mg/L非离子表面活性剂TritonX-100进行修复时,洗脱率分别为70.5%和12.7%。可以知道,由于野外污染土壤污染时间已经达到10年～20年,表面活性剂对于多氯联苯人工污染土壤的洗脱效果要明显好于野外污染土壤。总的来说,阴离子表面活性剂的修复效果要优于非离子表面活性剂。而修复效果还受到土壤中总有机碳含量、洗脱液容量、洗脱温度、洗脱方式以及采用重复洗脱等因素的影响。由实验可以知道,总有机碳含量越高,修复效果越差;在10℃～30℃情况下,温度的变化对洗脱效果没有明显的影响;增加洗脱液容量和采用重复洗脱的方式都能提高污染土壤的多氯联苯洗脱效果。当溶液体积和土壤质量的比例为20(ml):1(g)时,表面活性剂的洗脱效率最好;而采用2～3次重复洗脱时,洗脱效率最高;选用超声波振荡的方法,也可以提高表面活性剂的洗脱效率。根据以上的各种研究表明,使用表面活性剂洗脱多氯联苯污染土壤是一种有效的方法。更多还原

【Abstract】 Polychlorinated biphenyls are important environmental organic pollutants due to their carcinogenicity. They are physically and chemically stable, and resistant to degradation. Their strongly hydrophobic nature make them bind to soil tightly, resulting in remediation of PCB contaminated soils a challenge problem.Remediation of PCBs contaminated soils by surfactants was studied in the thesis. When an anionic surfactant, sodium dodecyl sulfate (SDS), was applied at 10000mg/L, 67.8% and 54.1% PCBs were washed out from a laboratory contaminated soil and a field contaminated soil, respectively, while 70.5% and 12.7% PCBs were washed out from the same soils, respectively, using an nonionic surfactant, TritonX-100 at 10000mg/L. These results indicate that the laboratory contaminated soil was easier to remediate than the field contaminated soil which has been polluted over 10 years. The SDS is better than the TritonX-100, in general, for washing PCBs from soils. Further, factors such as organic carbon fraction of soil, volume, temperature, and times of surfactant solvent applied, which affect on surfactant desorbing PCB from the soils were tested. It was found that the higher the organic carbon fraction of the soil, the lower the PCB washing efficiency; In the range of 10-30°C, temperature did not show definitely influence on the soil washing; Increasing volume of surfactant as well as the repeat washings leaded to increasing amount of PCB washed from soils, and 20(ml):l (g) ratio of surfactant to soil, and 2-3 repeat washings were the most effective for the soil washing under the test conditions. Ultrasonification could also improve surfactant soil washing efficiency and reduce the quantity of surfactant adsorbed by soil. Based on the results, it may conclude that surfactant soil washing is a viable way for remediation of PCBs contaminated soils.更多还原