螯合型表面活性剂修复石油-镉复合污染土壤研究

Study on remediation of petroleum-cadmium co-contaminated soil by chelating surfactant

针对石化类污染场地普遍存在的石油与重金属复合污染问题,利用螯合型表面活性剂N-acyl ED3A开展石油-Cd复合污染土壤修复研究。结果表明,淋洗液pH是影响石油增溶、Cd螯合效果的主要因素,Cd螯合反应平衡时间(90 min)显著短于石油增溶平衡时间(12 h)。最佳淋洗条件下石油和Cd的同步洗脱效率分别达到50.8%和56.4%,但洗脱动力学过程存在差异与洗脱效率及洗脱平衡时间差异和共存于土壤时的交互作用有关。石油和Cd污染物主要存在于黏粒组分,占比分别达64.5%和55.3%,土壤黏粒组分占比高、洗脱效率低(石油为31.6%、Cd为34.4%)是影响整体修复效率的主要原因。

This study aims to identify the application feasibility of chelating surfactant(N-acyl ED3A)in the remediation of petroleum-cadmium co-contaminated soil,which is a common issue in petrochemical contaminated sites.The results indicate that p H of washing solution is the major factor that affects the dissolve of petroleum and chelate of cadmium.It takes approximately 90 minutes for Cd chelation reaction to reach equilibrium,which is much shorter than the 12 hours needed for petroleum dissolve to reach equilibrium.The simultaneous removal efficiencies of petroleum and cadmium can reach 50.8%and 56.4%,respectively under the optimum soil washing conditions.The elution reaction kinetics of petroleum and cadmium are different during the remediation process of co-contaminated soils,which may be contributed by different elution efficiency and elution equilibrium time of the two contaminants,and their interaction due to their coexisting in soil.Petroleum and cadmium mainly exist in clay fraction of the co-contaminated soils,which accounts for 64.5%and 55.3%of the total amount of pollutants severally.High proportion of clay fraction in soil and low elution efficiency(petroleum 31.6%,cadmium 34.4%)for clays are the main reasons affecting overall remediation efficiency.