Mechanism of deleading of silicate glass by 0.5N HNO3

Sadrnezhaad, S.K.; Rahimi, Rafi Ali; Raisali, Gholamreza; Foruzanfar, Farhad

doi:10.1016/j.jnoncrysol.2009.08.019

Cited by 4 publications

(3 citation statements)

References 16 publications

(36 reference statements)

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“…Numerous empirical studies have been carried out to examine the Pb leaching from glass or from glass ceramic in reactive environments, particularly in contact with different actual beverages or simple synthetic solutions such as acetic acid or nitric acid [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . In commercial lead crystal glasses, it has generally been observed that the release of alkalis and Pb ions exhibited a square root time dependence through a diffusion process 11,15,17,18 .…”

Section: Introductionmentioning

confidence: 99%

“…Numerous empirical studies have been carried out to examine the Pb leaching from glass or from glass ceramic in reactive environments, particularly in contact with different actual beverages or simple synthetic solutions such as acetic or nitric acid. − In commercial lead crystal glasses, it has generally been observed that the release of alkalis and Pb ions exhibited a square root time dependence through a diffusion process. ,,, Their leaching kinetics usually increase with the temperature and with the acetic acid concentration . During successive contacts, a decrease in the release of Pb has been observed with each additional solution contact .…”

Section: Introductionmentioning

confidence: 99%

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Structure and Chemical Durability of Lead Crystal Glass

Angeli

Jollivet

Charpentier

et al. 2016

Environ. Sci. Technol.

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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 % of PbO (28.3 wt %) was studied in a reference solution of 4% acetic acid at 22, 40, and 70 °C at early and advanced stages of reaction. High-resolution solid-state O andSi 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.

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Section: Introductionmentioning

confidence: 99%

“…Numerous empirical studies have been carried out to examine the Pb leaching from glass or from glass ceramic in reactive environments, particularly in contact with different actual beverages or simple synthetic solutions such as acetic or nitric acid. − In commercial lead crystal glasses, it has generally been observed that the release of alkalis and Pb ions exhibited a square root time dependence through a diffusion process. ,,, Their leaching kinetics usually increase with the temperature and with the acetic acid concentration . During successive contacts, a decrease in the release of Pb has been observed with each additional solution contact .…”

Section: Introductionmentioning

confidence: 99%

Structure and Chemical Durability of Lead Crystal Glass

Angeli

Jollivet

Charpentier

et al. 2016

Environ. Sci. Technol.

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“…Based on the previous pieces of research, lead ion acts as a network modifier at less than 70 wt% or 50 mol% in lead silicate glasses . In water or aqueous acid solutions, the network dissolution can often be neglected, especially for the glasses with higher content of silica, and no gel‐like layer can be found on the surface of glasses; hence, a single‐step diffusion process can be sufficient for explaining the migration results in the dilute acid solutions or water . In addition, the mechanism of migration of cadmium from glass is believed to be similar to that of lead .…”

Section: Introductionmentioning

confidence: 99%

Migration Model of Toxic Metals from Ceramic Food Contact Materials into Acid Food

Dong

Liu

2015

Packag Technol Sci

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Migration studies of lead and cadmium from ceramic food contact materials into acid food simulants were conducted under various time-temperature conditions to investigate the kinetics of the leaching of lead and cadmium. A mathematical model based on one-dimensional Fickian diffusion theory was derived in order to describe the migration behaviour of lead and cadmium. Moreover, diffusion coefficients of toxic metals were obtained by fitting the short-time (24 h) migration data to the model. Comparisons of model solutions with experimental data obtained from the medium-time tests (up to 600 h) and long-time tests (up to 130 days) were carried out to verify the proposed model and the values of diffusion coefficients obtained from the short-time test. Results show that the model fits the experimental data obtained under 20 and 40°C well but fails to fit the experimental data at 60°C. This indicates a change of the migration mechanisms from ion exchange to glass network dissolution as a result of higher temperature. Furthermore, results of migration experiments also reveal that the effects of temperature on the diffusion of lead and cadmium follow the Arrhenius law and that the leaching amounts of lead and cadmium decrease with pH value of the food simulant.

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