Mechanism of calcium lixiviation in soda-lime glasses with a strong biocide activity

Abstract

In a recent work, it has been proved that soda-lime glasses, belonging to the SiO2–Na2O–CaO–B2O3 system with a high content of calcium oxide (15 to 20 wt.%), are efficient biocides against Gram positive, negative bacteria and yeast. In the present work we discuss the possible mechanism responsible for the biocide action of these series of glasses against Escherichia coli microorganisms. The local structure of these glasses has been investigated by MAS-NMR spectroscopy. The importance of the strength with which calcium is retained in the glass structure has been pointed out. This strength decreases as the condensation degree of tetrahedral in the glass structure decreases, as a consequence the biocide activity also increases.