Speaker
Description
Although zeolites are very important for many industries, their formation is still not fully understood due to the difficult experimental conditions in which formation occurs. On the other hand, theoretical models have been hampered by the troublesome modeling of hydrogen bonds present in the crucial water solvent. Recently, a new synthesis route was proposed whereby the main problems for direct observation and characterization – pressure build-up and gel-formation – are evaded. [1] Furthermore, in these circumstances the formation of zeolites occurs at the rate of aluminum addition, allowing a very controlled propagation of the formation process. These so-called hydrated silicate ionic liquids (HSILs), which are fully clear and contain no particles, are currently under intense experimental investigation in order to characterize the ionic liquid, assess the role of aluminum in the process and construct a generally valid model for zeolite formation leading to controlled zeolite synthesis.
Given the low amount of water, the presence of only small molecular (alumino)silica species – such as monomers, dimers, 3- and 4-rings – and the fact that formation only starts upon introduction of low amounts of aluminum, accurate molecular modeling of these systems also becomes feasible. This is important as it is widely known that the topology of the zeolite is governed by the cations present in the synthesis medium. As such, accurate modeling of HSIL is expected to give important insights into the structure directing effects of the synthesis conditions towards the final zeolite topology. In this work we used molecular dynamics simulations with appropriately validated force fields to characterize the ionic liquid in close collaboration with experimental results.
[1] L. van Tendeloo, M. Haouas, J. A. Martens, C. E. A. Kirschhock, E. Breynaert and F. Taulelle, Faraday Discuss., 2015, 179, 437-449
| Speaker Country | Belgium |
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