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Masoud Farhadi Khouzani has been selected to participate in the 63rd Lindau Nobel Laureate Meeting, to be held from 30th June to 5th July 2013. Only the 550 most qualified young researchers can be given the opportunity to enrich and share the unique atmosphere of the Lindau Nobel Laureate Meetings. Congratulations, Masoud!
Denis Gebauer has been awarded a fellowship of the Zukunftskolleg of the University of Konstanz.
CrystEngComm article "Porous tablets of crystalline calcium carbonate via sintering of amorphous nanoparticles" available online
Abstract. Porous tablets of crystalline calcium carbonate were formed upon sintering of a precursor powder of amorphous calcium carbonate (ACC) under compressive stress (20 MPa) at relatively low temperatures (120-400ºC), induced by pulsed direct currents. Infrared spectroscopy ascertained the amorphous nature of the precursor powders. At temperatures of 120-350ºC and heating rates of of 20-100ºC/min, the nanoparticles of ACC transformed into crystallites of mainly aragonite, which is generally difficult to achieve using wet-chemicals under kinetic control. The amorphous precursor particles (~10 nm) transformed into crystallites (~30-50 nm) during sintering. Consistently, the specific surface areas of 140-160 m2/g for the precursor particles were reduced to 10-20 m2/g for the porous sintered tablets. The porous network within the tablets consisted of fused aragonite and vaterite particles in a ratio of ~80:20. The fraction of aragonite to vaterite was invariant to the temperature and heating rate used. The particle size increased only slightly on an increased heating rate. At temperatures above 400ºC, porous tablets of calcite formed under thermodynamic control together with a minor reduction of the specific surface area of the tablets. The size of the crystallites remained small, and the transformation to calcite appeared to be a solid-state transformation. Porous, template- and binder-free tablets of calcium carbonate could find applications in, for example, biology or water treatment. [D. Gebauer, X. M. Liu, B. Aziz, N. Hedin and Z. Zhao, CrystEngComm 15, 1257 (2013), DOI: 10.1039/C2CE26604K]