Control of nucleation and crystallization of Al(III)(oxy)(hydr)oxides: An avenue toward advanced materials
Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
Final Report Abstract
Aluminium in its +3 oxidation state, Al(III), is environmentally significant due to its prevalence in minerals and potential ecological impacts, essential for humans in various industrial applications like water treatment, with certain ramifications for human health, and a key focus in chemical science due to its reactivity for advanced material development. This project was devoted to the exploration of the early stages of Al(III)(oxy)(hydr)oxide formation in presence of model organic additives: fumaric, polyacrylic, polyaspartic, polyglutamic, and ellagic acid. These additives represent molecules occurring in natural and physiological environments, but are also important in syntheses of hybrid metal-organic materials. They possess versatile chemical functionalities for the interaction with Al(III) species. The investigated additives, as well as other chemicals used in the project, are non-toxic and environmentally safe. Thus, the relevance of the project relates to all aspects of the aqueous chemistry of Al(III): The behaviour of Al(III) species in soil and aquatic basins and their interaction with organic matter, syntheses of catalytic alumina-based materials, Al(III)-based drug additives in pharmaceutical contexts, the interaction of Al(III) species with physiologically important molecules, the synthesis of novel hybrid inorganic-organic materials, and many more. Although the interactions of Al(III) species with organic compounds are extensively studied, recent findings in terms of nucleation and crystallization mechanisms of Al(III)(oxy)(hydr)oxides have generally not been considered. This is especially true for the so-called non-classical nucleation (pre-nucleation cluster) theory, leading to a lack of understanding of the interactions occurring in the early stages of solid formation. The fundamental process determining the chemical behaviour in aqueous solutions, with or without additives, is Al(III) hydrolysis; however, it occurs in a very narrow pH range of ~4-6, rendering the interactions extremely complex and hard to control. To resolve this issue, we developed advanced potentiometric titration techniques and studied the Al(III) hydrolysis behaviours and interactions with additives at low driving force for phase separation across a broad pH range, from acidic to neutral conditions. As-prepared, carefully controlled chemical states enabled us to tune the hydrolysis extent and systematically explore the interactions with additives. A range of methods was used for the characterization of not only the derived solids (electron microscopy, thermal analysis, vibrational spectroscopy, isothermal titration calorimetry, etc.). Altogether, we developed optimized approaches for studying Al(III)-additive interactions and the determination of corresponding thermodynamic parameters. The results provide detailed insights that are of great fundamental value, but can also be exploited in, e.g., target-oriented materials synthesis.
Publications
-
Homogeneous nucleation in the Al(II) system in the presence of organic additives; Understanding crystallization: Faraday Discussions, 28-30 March 2022, York, United Kingdom (poster presentation, Book of abstracts, P10)
Miodrag J. Lukic & Denis Gebauer
-
Nucleation of the Al(III)-(oxy)(hydr)oxides in the presence of polyamino acids; 9th Granada-Münster Discussion Meeting, 30 November – 02 December 2022, Granada, Spain (oral presentation)
Miodrag J. Lukic & Denis Gebauer
-
Role of Water during the Early Stages of Iron Oxyhydroxide Formation by a Bacterial Iron Nucleator. The Journal of Physical Chemistry Letters, 15(4), 1048-1055.
Qi, Daizong; Lukić, Miodrag J.; Lu, Hao; Gebauer, Denis & Bonn, Mischa
-
The Chemistry of Phase Separation in Aqueous Hydrolyzing Metal Systems: Aluminium(III) and Iron(III). Topics in Applied Physics, 45-78. Springer Nature Singapore.
Lukić, Miodrag J. & Gebauer, Denis
