He Xiao, Liu Qingxia, Xu Zhenghe
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada; Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
J Colloid Interface Sci. 2020 May 15;568:207-220. doi: 10.1016/j.jcis.2020.02.019. Epub 2020 Feb 7.
Interfacially active magnetic Janus nanoparticles (M-Janus NPs) of asymmetric surface wettability are more interfacially active than biwettable nanoparticles (M-CMC-EC NPs) of uniform surface wettability as such that they could anchor more securely at an oil-water interface to separate emulsified oil droplets from oily wastewaters more effectively by magnetic separation.
Interfacial tension and interfacial pressure-area isotherms of M-Janus NPs at oil-water interface were measured and the results were correlated to coalescence time of oil droplets determined in various types of aqueous phase (wastewaters) and to the performance of oil removal or recovery from corresponding oily wastewaters by M-Janus NPs and M-CMC-EC NPs of uniform surface wettability by an external magnetic field.
Despite the presence of natural/synthetic surfactants in the oily wastewaters, M-Janus NPs exhibited stronger interfacial activities and anchored more firmly at oil-water interfaces than M-CMC-EC NPs of uniform surface wettability. The application of M-Janus NPs could remove/recover >91.5% oil from oily wastewaters by an external magnetic field as compared with >84.3% achieved by M-CMC-EC NPs of uniform surface wettability for treating different oily wastewaters. The M-Janus NPs could be facilely recycled and efficiently reused in the subsequent applications to oil removal/recovery without complex regeneration.
具有不对称表面润湿性的界面活性磁性Janus纳米颗粒（M-Janus NPs）比具有均匀表面润湿性的双润湿性纳米颗粒（M-CMC-EC NPs）具有更高的界面活性，因此它们可以更牢固地锚定在油水界面，通过磁分离更有效地从含油废水中分离乳化油滴。
测量了M-Janus NPs在油水界面的界面张力和界面压力-面积等温线，并将结果与在各种水相（废水）中测定的油滴聚并时间以及通过外部磁场对具有均匀表面润湿性的M-Janus NPs和M-CMC-EC NPs从相应含油废水中去除或回收油的性能相关联。
尽管含油废水中存在天然/合成表面活性剂，但M-Janus NPs比具有均匀表面润湿性的M-CMC-EC NPs表现出更强的界面活性，并更牢固地锚定在油水界面。与具有均匀表面润湿性的M-CMC-EC NPs处理不同含油废水时达到的>84.3%相比，应用M-Janus NPs通过外部磁场可从含油废水中去除/回收>91.5%的油。M-Janus NPs可以轻松回收，并在随后的除油/回收应用中高效重复使用，无需复杂的再生过程。
