表面活性剂增溶洗脱土壤中多环芳烃的效果研究

表面活性剂增效洗脱修复技术被广泛应用于土壤修复. 本文选取11种非离子型和3种离子型表面活性剂对多环芳烃(PAHs，菲、芘、苯并a]芘)污染土壤进行洗脱研究，筛选出洗脱效果较好的表面活性剂，并深入探索表面活性剂浓度、洗脱时间、固液比等因素以及表面活性剂的复配对土壤PAHs增效洗脱的影响，旨在比选出一种高效洗脱土壤PAHs的表面活性剂并对其洗脱方法进行优化. 结果表明:①表面活性剂浓度为10 g/L、固液比为1∶20条件下，聚氧乙烯醚-10(NSF10)的去除率最高，达到78%；其次为曲拉通X-100(TX-100)和吐温80(TW-80)，去除率分别为76.7%和73.4%. ②随着表面活性剂添加浓度的增加，土壤PAHs的去除率增大，当表面活性剂浓度超过5 g/L时，PAHs去除率的增幅减缓，可见，5 g/L是相对有效且经济的表面活性剂添加浓度. ③当洗脱时间为16 h时，NSF10对PAHs的洗脱达到平衡，继续延长洗脱时间，洗脱效果并未增强. ④增加NSF10用量有利于洗脱，固液比1∶40是最优固液比，此时PAHs的去除率已达到固液比为1∶100时的85.2%. ⑤非离子表面活性剂NSF10、TX-100、TW-80与阴离子表面活性剂SDS分别以体积比9∶1进行复配时均取得了优于单一活性剂的洗脱效果，NSF10与SDS体积比为7∶3时，增溶洗脱效果最为明显，比单一表面活性剂提高了18.2%. 研究显示，NSF10是一种高效的PAHs洗脱剂，添加浓度为5 g/L、洗脱时间为16 h、固液比为1∶40是其最优参数选择，其与SDS以体积比7∶3进行复配可进一步提升增溶洗脱效果. 

Surfactant-Enhanced Solubilization and Elution of Polycyclic Aromatic Hydrocarbons in Soil

Surfactant-enhanced remediation technology is widely used in soil remediation. In this study, 11 types of non-ionic surfactants (including 5 non-ionic biosurfactants) and 3 ionic surfactants (2 anionic and 1 cationic biosurfactants) were selected for the remediation of soil contaminated with PAHs (phenanthrene, pyrene and benzoa] pyrene). The surfactants with better elution effects were screened, and the effects of factors, such as surfactant concentration, elution time, solid-liquid ratio, and nonionic to anionic surfactant ratio, on the elution of PAHs in soil were further investigated in order to optimize the elution method. The results showed that non-ionic surfactants had a better elution effect on PAHs in soil than ionic surfactants. When the surfactant concentration was 10 g/L and solid-to-liquid ratio was 1∶20, the elution rate of polyoxyethylene ether -10 (NSF10) reached 78%, followed by Triton X-100 (76.7%) and Tween 80 (73.4%). The two anionic surfactants, sodium dodecyl sulfonate (SDS) and sodium dodecylbenzene sulfonate (SDBS), had an elution rate of less than 1% for PAHs in soil, which is ineffective. The elution rate of PAHs varied significantly with varying surfactant concentration. As the concentration increased, the elution rate increased linearly. When the concentration increased to 5 g/L, the elution rate increased rapidly. For example, the elution rate of NSF10 increased from 17.9% at 1 g/L to 60.4% at 5 g/L. The elution rate increased by 237.4% when it reached 10 g/L, and the elution rate increased by only 20.2% compared with 5 g/L. When the elution time was 16 h, the elution of PAHs by NSF10 reached equilibrium. When the elution time was extended, the elution effect was not enhanced. Increasing the volume of surfactants improved the elution of PAHs. The solid-liquid ratio of 1∶40 was the optimal solid-liquid ratio. At this ratio, the elution rate was 85.2% of that at a solid-liquid ratio of 1∶100. When non-ionic surfactants (NSF10, TX-100 and TW-80) and anionic surfactant SDS were mixed at a volume ratio of 9∶1, the elution effect was better than that of a single surfactant. When the volume ratio of NSF10∶SDS was 7∶3, the solubilization and elution effect were the most obvious, which was 18.2% higher than that of single surfactant. The results show that NSF10 was a high-efficiency eluent for PAHs, and the optimum synergistic elution effect was achieved at the concentration of 5 g/L, the elution time of 16 h and the solid-liquid ratio of 1∶40. It can achieve synergistic elution effect when NSF10 is mixed with SDS at the volume ratio of 7∶3.