Destructing surfactant network in nanoemulsions by positively charged magnetic nanorods to enhance oil-water separation.
Destructing surfactant network in nanoemulsions by positively charged magnetic nanorods to enhance oil-water separation.
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DOI：
10.1016/j.jes.2021.08.039
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发表时间：
2022
影响因子：
6.9
通讯作者：
Yongjiao Xiong;Xiang-feng Huang;Lexue Li;Wanqi Liu;Jialu Zhang;Mengfan He;Jia Liu;Li-jun Lu;Kaiming Peng
中科院分区：
文献类型：
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作者：
Yongjiao Xiong;Xiang-feng Huang;Lexue Li;Wanqi Liu;Jialu Zhang;Mengfan He;Jia Liu;Li-jun Lu;Kaiming Peng
从高浓度表面活性剂稳定的废弃纳米乳液中分离出超细油滴是油脂回收利用和废水安全排放的前提。然而，纳米乳液中表面活性剂形成的界面膜和网络结构的双重屏障严重阻碍了油水分离。为了破坏这些表面活性剂的保护层，我们提出了一种新开发的聚乙烯亚胺胶束模板的方法来实现同时的表面电荷操纵和磁性纳米球的磁性纳米棒的形态转变。结果表明，带正电荷的磁性纳米球表现出有限的纳米乳液的分离性能，最大化学需氧量（COD）去除率为50%，而磁性纳米棒实现了95%以上的COD去除在不到30 s。磁性纳米棒也适用于废弃的纳米乳液从不同的来源，并表现出良好的抵抗广泛的pH值变化。由于其独特的一维结构，磁性纳米棒的界面分散显着促进，导致表面活性剂的有效捕获和界面膜和网络结构的广泛破坏，这有利于液滴合并到油相。该方法易于制备和调控，为同时调控磁性纳米粒子的表面电荷和形貌提供了一条可行的途径，揭示了形貌调控在制备高性能纳米材料以应用于复杂界面相互作用过程中的巨大潜力。我们相信，新开发的磁性纳米棒对危险含油废物的修复做出了重大贡献，并推动了石油污染控制技术的发展。
The separation of ultrafine oil droplets from wasted nanoemulsions stabilized with high concentration of surfactants is precondition for oil reuse and the safe discharge of effluent. However, the double barriers of the interfacial film and network structures formed by surfactants in nanoemulsions significantly impede the oil-water separation. To destroy these surfactant protective layers, we proposed a newly-developed polyethyleneimine micelle template approach to achieve simultaneous surface charge manipulation and morphology transformation of magnetic nanospheres to magnetic nanorods. The results revealed that positively charged magnetic nanospheres exhibited limited separation performance of nanoemulsions, with a maximum chemical oxygen demand (COD) removal of 50%, whereas magnetic nanorods achieved more than 95% COD removal in less than 30 s. The magnetic nanorods were also applicable to wasted nanoemulsions from different sources and exhibited excellent resistance to wide pH changes. Owing to their unique one-dimensional structure, the interfacial dispersion of magnetic nanorods was significantly promoted, leading to the efficient capture of surfactants and widespread destruction of both the interfacial film and network structure, which facilitated droplet merging into the oil phase. The easy-to-prepare and easy-to-tune strategy in this study paves a feasible avenue to simultaneously tailor surface charge and morphology of magnetic nanoparticles, and reveals the huge potential of morphology manipulation for producing high-performance nanomaterials to be applied in complex interfacial interaction process. We believe that the newly-developed magnetic-nanorods significantly contribute to hazardous oily waste remediation and advances technology evolution toward problematic oil-pollution control.