<abstract xmlns="http://www.w3.org/1999/xhtml">Mimetite Pb5(AsO4)3Cl is the most insoluble lead arsenate mineral and could be used in remediation techniques to reduce As(V) mobility in soils. However, low-molecular-weight organic acids such as malic acid increase its solubility. The effect of malic acid on the dissolution of mimetite strongly depends on the pH of the equilibrium solution. At low pH, mimetite is decomposed mostly by the mechanism of protonation. With increasing pH, the solubility of mimetite decreases and a greater influence in its dissolution is ascribed to complexation of Pb(II) by organic ligands. During dissolution experiments, the amount of arsenic released to solution was > 26% higher in organic solutions than in inorganic solutions, and the amount of lead was > 8% greater. The solubility product of mimetite (KSP) was calculated in order to quantify the thermodynamic stability of the investigated mineral. The value obtained, i.e., -24.52 ± 0.49 fluctuates between the values of -21.69 ± 1.05 and -27.87 ± 0.42 reported in the literature.</abstract>

Mimetite Pb5(AsO4)3Cl is the most insoluble lead arsenate mineral and could be used in remediation techniques to reduce As(V) mobility in soils. However, low-molecular-weight organic acids such as malic acid increase its solubility. The effect of malic acid on the dissolution of mimetite strongly depends on the pH of the equilibrium solution. At low pH, mimetite is decomposed mostly by the mechanism of protonation. With increasing pH, the solubility of mimetite decreases and a greater influence in its dissolution is ascribed to complexation of Pb(II) by organic ligands. During dissolution experiments, the amount of arsenic released to solution was > 26% higher in organic solutions than in inorganic solutions, and the amount of lead was > 8% greater. The solubility product of mimetite (KSP) was calculated in order to quantify the thermodynamic stability of the investigated mineral. The value obtained, i.e., -24.52 ± 0.49 fluctuates between the values of -21.69 ± 1.05 and -27.87 ± 0.42 reported in the literature.

Dissolution of mimetite Pb5(AsO4)3Cl in malic acid solutions

AGH University of Science and Technology, Faculty of Geology, Geophysics and Environmental Protection, Department of Mineralogy, Petrography and Geochemistry, al. Mickiewicza 30, 30-059 Kraków, Poland

Mineralogia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Dissolution of mimetite Pb(AsO)Cl in malic acid solutions

Mimetite Pb5(AsO4)3Cl is the most insoluble lead arsenate mineral and could be used in remediation techniques to reduce As(V) mobility in soils. However,...

Dissolution of mimetite Pb₅(AsO₄)₃Cl in malic acid solutions

Published Online: Jul 01, 2015

Page range: 3 - 12

Received: Jul 24, 2013

Accepted: Sep 24, 2014

DOI: https://doi.org/10.2478/mipo-2014-0001

Keywords
organic acid, lead, arsenic, solubility product

© by Tomasz Bajda

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Dissolution of mimetite Pb5(AsO4)3Cl in malic acid solutions

Published Online: Jul 01, 2015

Page range: 3 - 12

Received: Jul 24, 2013

Accepted: Sep 24, 2014

DOI: https://doi.org/10.2478/mipo-2014-0001

Keywordsorganic acid, lead, arsenic, solubility product

© by Tomasz Bajda

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Dissolution of mimetite Pb₅(AsO₄)₃Cl in malic acid solutions

Keywords
organic acid, lead, arsenic, solubility product