Polyfluoroalkyl Substances (PFAS) such as perfluorooctanoic acid (PFOA) are resistant to biodegradation leading to adverse health outcomes. Therefore, PFAS removal from drinking water is paramount. Liquid-liquid extraction processes can remove them from water; however, the hydrophobic and oleophobic properties of PFOA lead to the low extraction efficiency and severe emulsification, especially for the ppm-levels concentration of PFOA. Therefore, we introduced ionic liquid (IL) methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([A336][NTf₂]) as extractant into octanol. We found that using hexadecyl trimethyl ammonium bromide (CTAB) as an extractant caused severe and stable emulsion. In comparison, [A336][NTf₂] could suppress the emulsification with high extraction efficiency. The extraction performance of PFOA was examined as a function of various parameters. The results showed that the extraction efficiency was strongly dependent on the concentration of IL and aqueous pH. Further research revealed the extraction mechanisms at the molecular-level, and density functional theory (DFT) and molecular dynamic (MD) simulation agreed with the trends in the experiment. We determined that the extraction efficiency of PFOA from water could be up to 88.21 wt% for the optimized condition, indicating that the extraction system of [A336][NTf₂] + octanol was efficient for separating PFOA from the diluted aqueous solution.

全氟辛酸（PFOA）等多氟烷基物质（PFAS）可以抵抗生物降解，从而导致不良的健康后果。因此，从饮用水中去除PFAS至关重要。液-液萃取过程可以将其从水中去除；然而，PFOA的疏水和疏油性能导致萃取效率低和严重的乳化作用，特别是对于ppm级的PFOA浓度。因此，我们将离子液体（IL）甲基三辛基铵双（三氟甲基磺酰基）酰亚胺（[A336] [NTf ₂ ]）引入辛醇中。我们发现使用十六烷基三甲基溴化铵（CTAB）作为萃取剂会导致严重而稳定的乳液。相比之下，[A336] [NTf ₂可以抑制乳化，提取效率高。根据各种参数检查了PFOA的提取性能。结果表明，提取效率强烈依赖于IL浓度和pH水溶液。进一步的研究揭示了分子水平的提取机理，密度泛函理论（DFT）和分子动力学（MD）模拟与实验趋势相吻合。我们确定，在最佳条件下，从水中提取PFOA的效率可高达88.21 wt％，这表明[A336] [NTf ₂ ] +辛醇的提取系统可有效地从稀释的​​水溶液中分离PFOA。