It is shown that soda‐lime glass powders (d < 100 µm) with a content of CaO ranging from 15 to 20 wt‐% are strong inorganic biocide agents, with a logarithm of reduction > 4, versus Gram‐positive and Gram‐negative bacteria, and yeasts. First, the glass particles are attached to the cell membrane; then, the Ca2+ lixiviated from the glass particles surface brings about membrane depolarization and subsequent death of the cells.

A new pressureless hydrothermal method for the preparation of yttrium disilicate is presented. The obtained amorphous precursor was calcined at different temperatures to form the Y-, R-, β-, and γ-phases of Y 2 Si 2 O 7 , which have been characterized by DTA, XRD, TEM, and 29 Si-MAS RMN and IR spectroscopy. It is shown that the proposed method allows the strictly controlled doping of yttrium disilicate using RE elements such as dysprosium (2.5 and 5 at. %). The luminescent properties, in terms of emission efficiency, of different polymorphs of Dy-doped Y 2 Si 2 O 7 have been investigated by fluorescence measurements at room temperature. The results indicate that the β-phase doped with 2.5 at.% has the maximum efficiency. It is important to note that the efficiency of this phase is approximately 40% of that measured for the commercial phosphor Eu-Y 2 O 3 .

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Luminescence D 6540Synthesis, Thermal Evolution, and Luminescence Properties of Yttrium Disilicate Host Matrix. -The Y-, α-, β-, and γ-phases of Y2Si2O7 are synthesized by calcination of an amorphous precursor at different temperatures between 1200 and 1600°C. The precursor is precipitated from solutions of Si(OEt)4 in EtOH and Y(NO3)3 in H2O by addition of NH3 (80°C, 6 h). The samples are characterized by DTA, XRD, TEM, and 29 Si MAS NMR and IR spectroscopy. The luminescence properties of different polymorphs of Dy-doped Y2Si2O7 are characterized by fluorescence measurements at room temperature. The β-phase doped with 2.5 at% Dy has the maximum emission efficiency, approximately 40% of that measured for the commercial Y2O3:Eu phosphor, and is an excellent candidate for optical applications. -(DIAZ, M.; PECHARROMAN, C.; DEL MONTE, F.; SANZ, J.; IGLESIAS*, J. E.; MOYA, J. S.; YAMAGATA, C.; MELLO-CASTANHO, S.; Chem.