Separation and purification of nanoparticles in a single step.
Separation and purification of nanoparticles in a single step.
复制标题
一步分离和纯化纳米颗粒。
作者：
M. Hollamby;J. Eastoe;A. Chemelli;O. Glatter;S. Rogers;R. Heenan;I. Grillo
反胶束合成已被用于生成cab稳定的金（Au-NPs）和银纳米颗粒（Ag-NPs）。通过诱导相变和随后的背景支撑微乳液分离，可以从反应介质中提取和纯化NPs。在加入多余的水后，NPs浓缩成富含辛烷的上层相，而杂质和反应碎屑（尤其是CTAB）则进入富水的下层相。UV和(1)H NMR表明，可以从过量的CTAB和其他盐杂质中纯化出原始质量的82%的Au-NPs。浓缩和纯化的NPs可以通过溶剂去除干燥，然后在辛烷中重新分散。利用互补的小角中子和x射线散射技术（SANS和SAXS），对分离前和不含纳米颗粒的微乳以及分离后上相和下相的结构进行了分析。该方法也被应用于银纳米颗粒的合成和回收，但在更大的规模上。这种新方法与现有方法相比具有优势，因为它不使用额外的有机溶剂，能量需求低，并且不需要专业的表面活性剂。这里的新进展是，通过使用胶体系统来制备和支持纳米颗粒作为结构化溶剂，一种简单的软净化方法变得可行，否则用普通分子溶剂是不可能的。
Reversed-micelle synthesis has been used to generate CTAB-stabilized gold (Au-NPs) and silver nanoparticles (Ag-NPs). By inducing a phase transition and subsequent separation of the background supporting microemulsion, it has been possible to extract and purify the NPs from the reaction medium. After addition of excess water, the NPs concentrate into an upper octane-rich phase, with impurities and reaction debris (in particular CTAB) partitioning into the water-rich lower phase. UV and (1)H NMR showed that 82% of the original mass of Au-NPs can be purified from the excess CTAB and other salt impurities. The concentrated and purified NPs can be dried down, by solvent removal, and then redispersed in octane. Using the complementary techniques small-angle neutron and X-ray scattering (SANS and SAXS), the structures of microemulsions both with and without nanoparticles prior to separation, and in both upper and lower phases after separation, have been elucidated. The approach has also been applied to the synthesis and recovery of silver nanoparticles, but on a larger scale. This new approach compares favorably with existing methods as it uses no additional organic solvents, has a low-energy demand, and requires no specialist surfactants. The new advance here is that by using a colloidal system to prepare and support the nanoparticles as a structured solvent, a simple soft purification method becomes accessible, which is otherwise impossible with a normal molecular solvent.