Lorianne GINOT1, Sandrine DOURDAIN1, Fabrice GIUSTI2, Stéphane PELLET-ROSTAING2
1CEA Marcoule - ICSM, Bagnols-sur-Cèze, France
2CNRS - ICSM, Bagnols-sur-Cèze, France
Porous liquids are a novel class of liquid materials disclosing a significant and permanent porosity. Among them, silica-based porous liquids are promising for many applications due to their high porosity and poor toxicity. Their synthesis is usually based on hollow silica nanospheres whose surface is covalently grafted by amino organosilanes, forming thus a first basic surrounding layer. The liquid behavior is then obtained after treatment with a mono sulfate polyethylene glycol (PEG) ester leading to ionic interactions that establish between the protonated ammoniums (cationic part of organosilanes) and an anionic corona of PEG sulfate. The latter is also responsible for the high hydrophilicity of the porous liquid.
Considering the porous liquids as promising candidates for liquid-liquid extraction of metals, it became necessary to synthesize new water-immiscible hydrophobic porous liquids.
We propose a route for the synthesis of a new range of hydrophobic porous liquids by replacing the hydrophilic PEG canopy by a more hydrophobic one. This has been achieved by using poly(ethoxylated) alkylamines that were designed to react with silica hollow-spheres covered by sulfonic groups. Hydrophobicity and viscosity could be tuned by varying the chain lengths of the poly(ethoxylated) chains.
In this presentation I will describe the new synthesis pathway and I will show and comment the results that I obtained when I performed the physicochemical characterization of the different porous liquids synthesized by this new route. Finally, I will also give a brief overview of preliminary results that were obtained with tests concerning the extraction of rare earth elements. Furthermore, I will discuss a later interesting insight considering the functionalization of the hollow spheres with specific groups that can lead to a better separation of the targeted metals.