非离子及两性型碳氢表面活性剂对全氟辛酸在土壤中迁移的影响

Effects of nonionic and amphiphilic hydrocarbon surfactants on the transport of perfluorooctanoic acid in soils

碳氟型表面活性剂全氟辛酸(Perfuorooctanoic Acid,PFOA)的大量使用导致其与各类碳氢表面活性剂广泛共存于土壤-地下水环境中,对人体健康和生态安全存在潜在威胁.通过柱实验探究不同离子强度条件下(1.5 mmol·L^(-1)和30mmol·L^(-1)),非离子型碳氢表面活性剂烷基糖苷(Alkyl Polyglycoside,APG)及两性型碳氢表面活性剂十二烷基二甲基甜菜碱(Dodecyl Dimethyl Betaine,BS-12)对PFOA在两种饱和土壤中迁移行为的影响和作用机制.结果表明,APG能促进PFOA的迁移行为,其主控机制为APG与PFOA在土壤表面的竞争吸附作用;BS-12能通过对土壤表面负电荷的中和作用及疏水作用增强PFOA在土壤中的阻滞,抑制其迁移行为.因此,预测和评估PFOA在土壤中的迁移行为时,需考虑共存碳氢表面活性剂的影响.

The extensive use of perfluorooctanoic acid(PFOA)leads to its widespread coexistence with kinds of hydrocarbon surfactants in the subsurface environment,which has posed potential risks to human health and ecological security.In this study,column experiments were conducted to explore the effect of nonionic hydrocarbon surfactant alkyl polyglycoside(APG)and amphiphilic surfactant dodecyl dimethyl betaine(BS-12)on the transport of PFOA in two saturated soils under different ionic strength.The results showed that APG could promote the transport of PFOA due to its competitive adsorption with PFOA on the soil surface.BS-12 could inhibit the transport of PFOA by neturalizing the negative charge on soil surface and hydrophobic interaction.Therefore,the effects coexisting hydrocarbon surfactants should be considered when predicting and evaluating the transport behavior of PFOA in soils.