工艺参数对表面活性剂洗涤修复PAHs污染土壤的影响

采用土壤洗涤(soil-washing)技术,分别用TritonX-100和Tween-80为强化洗涤剂研究了搅拌强度、洗涤时间、表面活性剂浓度、液固比、温度和间歇搅拌6个工艺参数对PAHs污染土壤洗涤效果的影响。通过一系列烧杯搅拌实验得到最佳洗涤工艺参数。TritonX-100和Tween-80的最佳洗涤时间分别是30 min和60 min,其他工艺参数最佳条件均相同。分别是搅拌强度为250 r/min,表面活性剂浓度为5 g/L,液固比为10∶1,温度为室温和连续搅拌。在此最佳工艺参数条件下,污染土中PAHs的残留率<10%,基本上满足目标污染物的修复目标。应用表面活性剂强化洗涤技术修复PAHs污染土壤是合理和可行的。

Influence of operating parameters on surfactant-enhanced washing to remedy PAHs contaminated soil

Surfactant-enhanced(TritonX-100 and Tween-80) soil washing technology was applied to investigate the influence of stirring speed,washing time,surfactant concentration,liquid/solid ratio,temperature,and on-and-off mode on the final removal of PAHs from contaminated soil.The optimum operating parameters were gained through a series of beaker experiments.The optimum washing time is 30 and 60 min respectively with TritonX-100 and Tween-80 as surfactant.As far other process parameters,the optimum value is the same with TritonX-100 or Tween-80.The optimum values of stirring speed,surfactant concentration,liquid/solid ratio,temperature,and on-and-off mode are 250 r/min,5 g/L,room temperature and continuous stirring,respectively.The overall residual ratio is less than 10 % under the conditions of above obtained optimum parameter values,which is basically in compliance with the remediation goals for five target PAHs.Therefore,it is very reasonable and feasible to apply surfactant-enhanced soil washing to remedy PAHs contaminated soil.