Hybrid hollow silica nanospheres for separation chemistry Influence of synthesis parameters
Résumé
Nowadays, separation of chemical elements is an important stake for many applications. Although liquid-liquid extraction represents the most applied method at industrial scale, it involves many economic and environmental constraints related to the use of large quantities of solvents. There is therefore a growing interest for alternatives as solid-liquid separation and flotation processes which however, require re-designing the actual industrial installations and present limited performances, in terms of extraction capacity and selectivity.
This project proposes to evaluate a new approach allowing to maintain the existing separation installations, by replacing the organic phases of liquid-liquid extraction processes, with a porous liquid. Porous liquids were discovered in 2014 by the Oak Ridge Corporation. They are solid materials made up with hollow nanoparticles of silica, that present the particularity to become liquid when grafted with ionic functions. To date, these materials have only been tested for gas separation. Being at the exact junction between liquid-liquid and solid-liquid extraction processes, porous liquids would allow exploiting the advantages of the two processes.
Therefore, we propose to form new porous liquids based on various synthesis methods and to test them for extraction at both solid and liquid state. Various synthesis parameters were investigated to control and understand the morphology of the nanospheres as well as their effect on their future extraction properties. Size, shape and homogeneity of the particles could be changed and controlled. To complete this understanding, a Small Angle X-ray Scattering (SAXS) analysis (Fig.1) was done completed by Transmission Electron Microscopy