STRUCTURE AND CHEMICAL DURABILITY OF LEAD CRYSTAL GLASS

Frederic Angeli (1) , Patrick Jollivet (1) , Thibault Charpentier (2) , Maxime Fournier (1) , S. Gin (1)

1 SECM - Service d'Etudes du Comportement des Matériaux de Conditionnement
2 NIMBE UMR 3685 - Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M)

Silicate glasses containing lead, also called lead crystal glasses, are commonly used as food product containers, in particular for alcoholic beverages. Lead’s health hazards require major attention, which can first be investigated through the understanding of Pb release mechanisms in solution. The behavior of a commercial crystal glass containing 10.6 mol per cent of PbO (28.3 wt per cent) was studied in a reference solution of 4 per cent acetic acid at 22, 40, and 70C at early and advanced stages of reaction. High-resolution solid-state 17O and 29Si NMR was used to probe the local structure of the pristine and, for the first time, of the altered lead crystal glass. Inserted into the vitreous structure between the network formers as Si–O–Pb bonds, Pb does not form Pb–O–Pb clusters which are expected to be more easily leached. A part of K is located near Pb, forming mixed Si–O–(Pb,K) near the nonbridging oxygens. Pb is always released into the solution following a diffusion-controlled dissolution over various periods of time, at a rate between 1 and 2 orders of magnitude lower than the alkalis (K and Na). The preferential release of alkalis is followed by an in situ repolymerization of the silicate network. Pb is only depleted in the outermost part of the alteration layer. In the remaining part, it stays mainly surrounded by Si in a stable structural configuration similar to that of the pristine glass. A simple model is proposed to estimate the Pb concentration as a function of glass surface, solution volume, temperature, and contact time.

Keywords: Silicate glasses

Domains: Nuclear Theory [nucl-th]; Nuclear Experiment [nucl-ex]

Frederic Angeli, Patrick Jollivet, Thibault Charpentier, Maxime Fournier, S. Gin. STRUCTURE AND CHEMICAL DURABILITY OF LEAD CRYSTAL GLASS. Environmental Science and Technology, 2016, 50 (21), pp.11549-11558. ⟨10.1021/acs.est.6b02971⟩. ⟨cea-02388823⟩