Description du projet
Une meilleure compréhension des interactions ioniques dans les processus de cristallisation naturels
La cristallisation, la formation de l’état de cristal solide d’un produit chimique à partir d’un état liquide, est très répandue dans la nature. La compréhension des processus naturels de cristallisation à l’œuvre dans la croûte et le magma terrestres présente un intérêt pour les questions relatives à la sécurité de l’eau et au changement climatique. La nucléation, le point où le cristal commence à croître plutôt que de se dissoudre à nouveau en solution, définit la structure cristalline. Le rôle de la charge dans la nucléation au sein des solutions naturelles et l’effet de ces cristaux chargés sur la formation de nouveaux cristaux sont encore très peu connus. Le projet CRYSTAL CLEAR, financé par l’UE, renforce le pouvoir prédictif des modèles de nucléation naturelle pour nous permettre d’aborder d’importants défis avec une vision plus claire.
Objectif
All of the crystals that form in water on Earth are formed through reaction between oppositely charged ions. In these crystals, the ions are present in an ideal, charge-balanced ionic ratio. In contrast, the natural solutions in which they form, contain widely diverging ionic ratios. When crystals nucleate from natural solutions, they will be charged, and charge has a massive impact on the behaviour of small new crystals.
Most nucleation experiments have been conducted in solutions with charge-balanced ionic ratios. This leads to uncharged crystal formation, which can be described with nucleation theories based on uncharged gas condensation into droplets. My pilot data show that this does not apply when ionic ratios diverge. New crystals then form and grow much slower than expected. Similarly, in natural solutions, crystals are often expected to form, but they do not, and vice versa. Clearly, we still have no idea how, why and how fast crystals nucleate in Earth surface environments.
In this project, I will test the hypothesis that ionic ratio has a dramatic impact on nucleation: crystals will be charged, and this charge will determine their size, how and how fast they grow, aggregate, and transform.
I will conduct state-of-the-art experiments and analyses that will provide in situ knowledge of the impact of ionic ratio on the charge, size, growth, aggregation and transformation of nuclei. Experiments will be complemented with advanced modelling to derive charged-nuclei stability and surrounding water properties. The results will be assimilated in a new crystal nucleation theory.
CRYSTAL CLEAR will focus on barite, calcite and pyrite as examples of highly relevant Earth Materials. The outcome will be improved geoengineering options such as drinking water production and CO2 sequestration. My project will bring a new vision on crystal formation in nature, with radically improved predictions of rates and mechanisms, and a paradigm shift in nucleation theory.
Mots‑clés
Programme(s)
Régime de financement
ERC-COG - Consolidator GrantInstitution d’accueil
3584 CS Utrecht
Pays-Bas