Effect of hydro-oleophobic perfluorocarbon chain on interfacial behavior and mechanism of perfluorooctane sulfonate in oil-water mixture
Effect of hydro-oleophobic perfluorocarbon chain on interfacial behavior and mechanism of perfluorooctane sulfonate in oil-water mixture
复制标题
疏油全氟碳链对油水混合物中全氟辛烷磺酸界面行为及机理的影响
DOI：
10.1038/srep44694
复制
发表时间：
2017-03-16
影响因子：
4.6
通讯作者：
Xing, Baoshan
中科院分区：
文献类型：
--
作者：
Meng, Pingping;Deng, Shubo;Xing, Baoshan
全氟辛烷磺酸（PFOS）的全氟烃链具有疏水性和疏油性，其对PFOS在油水混合物中分布的影响及其机理尚不清楚。首次提出PFOS与烃类表面活性剂完全不同，只有在空气存在下才能对油水混合物起增溶作用。全氟化碳链排斥疏水性化合物，并且其疏油性随着有机溶剂极性的降低而增加。在油相中形成的乳状液含有高浓度的PFOS，导致水中PFOS减少。增加振荡速度、振荡时间、油体积和空气体积均能提高乳化效果，降低水中PFOS浓度。在沉降过程中，乳状液逐渐消失，浓缩的全氟辛烷磺酸释放到水中。提出了PFOS基于气泡的乳化机理，PFOS通过疏水疏油的氟碳链伸展到气泡中，并通过极性头分配到气泡界面。本研究澄清了对PFOS中全氟化碳链疏油性的模糊认识，有助于理解PFOS在水环境中油-水界面的迁移和归趋，以及废水中PFOS的强化去除。
Perfluorocarbon chain of perfluorooctane sulfonate (PFOS) is not only hydrophobic but also oleophobic, and its effect on PFOS distribution in oil-water mixture and underlying mechanism are unclear. For the first time, we propose that PFOS can emulsify oil-water mixture only in the presence of air, completely different from hydrocarbon surfactants. The perfluorocarbon chain repels hydrophobic compounds and its oleophobicity increases with decreasing polarity of organic solvents. The formed emulsion in oil phase contains high concentrations of PFOS, resulting in PFOS decrease in water. The increase of shaking speed and time as well as oil and air volume all increase the emulsification and decrease PFOS concentrations in water. During the settling process, the emulsion gradually disappears and the concentrated PFOS is released into water. The emulsification mechanism of PFOS based on air bubbles is proposed, and PFOS partitions to the interfaces of air bubbles with the hydro-oleophobic perfluorocarbon chain stretching into air bubbles and the polar head in water. This study clarifies the ambiguous understanding of the oleophobicity of perfluorocarbon chain in PFOS, and it is helpful for the understanding of the transport and fate of PFOS at oil-water interfaces in aquatic environments as well as the enhanced removal of PFOS from wastewater.