MME BILLARD Isabelle

I am studying the solution chemistry of metal ions in water and in innovative liquid systems, such as Ionic Liquids (ILs), Aqueous Biphasic Systems (ABS) and Deep Eutectic Solvents (DES).
- ILs are salts which melting temperature is equal or below T = 100°C. Some are hydrophobic enough to induce a meniscus when contacted with water phases, thus allowing metal extraction. Being salts, their solvating properties are totally different from those of traditional molecular organic solvents (benzene, toluene, kerosene etc.). Therefore, they can offer extraction efficiencies very different from what is possible with molecular solvents. However, they are rather expensive and their toxicity is still largely unknown owing to the number of possible ILs available. However, for those already screened, Ils mostly appear toxic. 
- ABS are ternary systems composed of water plus two other compounds (ILs, polymers, inorganic salts, acids etc…). Depending on used chemical conditions (mass percentages and temperature) these mixtures can be either in a monophasic or a biphasic state, thus allowing metal extraction in a reversible way. In such systems, water is the main ingredient, thus lowering costs, but the molecular phenomena at the heart of the biphasic/monophasic changes are still poorly understood, limiting the control and use of such systems for applied studies. Interestingly, some of their constituents (polymers, salts) are green enough to be accepted at the industrial scale.
- DES are binary mixtures with melting temperatures below what is predicted by classical thermodynamics. Some of them are also hydrophobic enough to induce a meniscus when contacted with water phases. Some of their ingredients are bio-sourced, or rather non-toxic (and cheap) materials, rendering them an interesting approach for industrial applications.

Be aware that ILs are unitary chemical compounds while DES and ABS are mixtures. Some ILs and DES, when contacted with water, depending on chemical composition and temperature, can lead to a phase separation (i.e. a meniscus is visible), thus to extraction. They therefore can be called ABS, in a general sense. In the litterature, at the moment, some authors tend however to place ILs, DES ans ABS in different extraction categories. I am more in line with a general vision, which considers these systems to present very similar behaviours, based on similar properties, such as mutual solubilities (either "large" or "limited") of each compound with water. After all, what does it matter what you call them, as long as they do the job? 

The fundamental aim of my research work is to understand and model, if possible, the extraction mechanisms and mass transfer kinetics of metal ions from one phase to another using ABS (either containing DES or ILs or whatsoever). Recently, neutron scattering and other optical techniques are used (ESRF and ILL) to follow micelle/agregat formation of ILs in ABS as a function of temperature, sample composition or time. This is done in collaboration with Drs. marie Plazanet and Elise Lorenceau, from LiPhy (Grenoble). On a more classical experimental approach, analytical techniques allow to determine the composition of the upper and lower phase as a function of chemical conditions. On this basis, extraction mechanisms can be proposed, translated into mathematical equations, and fitted to the experimental results.
The applied perspective of my work is to propose, test and implement from the lab scale to the (pre)-industrial scale, innovative ways to recycle metals ions from any type of wastes. i first dealt with permanent magnets and NiMH batteries but rapidly focused on liquid industrial baths such as pickling bath from the steel industry. These studies are performed in close collaboration with industrial partners and French or European academic colleagues. In the past years, three patents have been submitted on these topics.
Current applied projects (2025) concern new pickling baths.