Author:
Lenhardt Katharina R.,Breitzke Hergen,Buntkowsky Gerd,Reimhult Erik,Willinger Max,Rennert Thilo
Abstract
AbstractWe report here on structure-related aggregation effects of short-range ordered aluminosilicates (SROAS) that have to be considered in the development of synthesis protocols and may be relevant for the properties of SROAS in the environment. We synthesized SROAS of variable composition by neutralizing aqueous aluminium chloride with sodium orthosilicate at ambient temperature and pressure. We determined elemental composition, visualized morphology by microscopic techniques, and resolved mineral structure by solid-state 29Si and 27Al nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Nitrogen sorption revealed substantial surface loss of Al-rich SROAS that resembled proto-imogolite formed in soils and sediments due to aggregation upon freezing. The effect was less pronounced in Si-rich SROAS, indicating a structure-dependent effect on spatial arrangement of mass at the submicron scale. Cryomilling efficiently fractured aggregates but did not change the magnitude of specific surface area. Since accessibility of surface functional groups is a prerequisite for sequestration of substances, elucidating physical and chemical processes of aggregation as a function of composition and crystallinity may improve our understanding of the reactivity of SROAS in the environment.
Funder
Deutsche Forschungsgemeinschaft
Publisher
Springer Science and Business Media LLC
Reference98 articles.
1. Gérard, M., Caquineau, S., Pinheiro, J. & Stoops, G. Weathering and allophane neoformation in soils developed on volcanic ash in the Azores. Eur. J. Soil Sci. 58, 496–515 (2007).
2. Jongmans, A. G., Verburg, P., Nieuwenhuyse, A. & van Oort, F. Allophane, imogolite, and gibbsite in coatings in a Costa Rican Andisol. Geoderma 64, 327–342 (1995).
3. Basile-Doelsch, I. et al. Mineralogical control of organic carbon dynamics in a volcanic ash soil on La Réunion. Eur. J. Soil Sci. 56, 689–703 (2005).
4. Hiradate, S., Hirai, H. & Hashimoto, H. Characterization of allophanic Andisols by solid-state 13C, 27Al, and 29Si NMR and by C stable isotopic ratio, δ13C. Geoderma 136, 696–707 (2006).
5. Rennert, T. et al. Characterisation of Andosols from Laacher See tephra by wet-chemical and spectroscopic techniques (FTIR, 27Al-, 29Si-NMR). Chem. Geol. 363, 13–21 (2014).
Cited by
24 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献