Aggregation of nanoparticles in aqueous solutions of ionic liquids

- We investigate aqueous solutions containing ionic liquids and nanoparticles.
- Nanoparticle assembly in small clusters were filled with the confined solvent.
- We observe the partition of the ionic liquid between the bulk and the confined solvent.
- The confined ionic liquid may be used to extract solutes from aqueous solutions.

In this work we were concerned with interactions between ionic liquids (IL) and nanoparticles (NPs) dispersed in aqueous solutions leading to the formation of NP clusters of finite size. The NPs used were Al2O3 (d = 80 nm), TiO2 (d < 100 nm), and Fe3O4 (d < 100 nm). ILs were 1-butyl-3-methylimidazolium bromide ([BMIM][Br]) and 1-methacryloyloxypropyl-3-methylimidazolium bromide, [mcpmim][Br]. The latter compound was a new IL synthesized in our laboratory. It was demonstrated that ILs actively participate in the formation of NP aggregates suspended in aqueous solution filling the inter-particle space. The aggregates saturated with IL were used as extractors making it possible for the elimination of compounds dissolved in water. Results of the extraction of anthracene and salicylic acid from aqueous solutions were presented.