Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system

Thermodynamic models of the lead carbonate aqueous system have been used in prior studies to evaluate the effect of water chemistry on lead solubility and corrosion scale composition in water distribution systems. A common challenge in these studies is uncertainty arising from the thermodynamic equi...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	C. Kushnir, C. E. Robinson
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	cerussite drinking water hydrocerussite lead thermodynamic model uncertainty Environmental technology. Sanitary engineering TD1-1066
Acceso en línea:	https://doaj.org/article/6531be751e934bc493614a49c3089e7f
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:6531be751e934bc493614a49c3089e7f
record_format	dspace
spelling	oai:doaj.org-article:6531be751e934bc493614a49c3089e7f2021-12-02T07:52:02ZExploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system2709-80442709-805210.2166/wqrj.2021.017https://doaj.org/article/6531be751e934bc493614a49c3089e7f2021-11-01T00:00:00Zhttp://wqrjc.iwaponline.com/content/56/4/194https://doaj.org/toc/2709-8044https://doaj.org/toc/2709-8052Thermodynamic models of the lead carbonate aqueous system have been used in prior studies to evaluate the effect of water chemistry on lead solubility and corrosion scale composition in water distribution systems. A common challenge in these studies is uncertainty arising from the thermodynamic equilibrium constants (logK values) used to parameterize the models. The objective of this study is to evaluate the way in which uncertainty in logK values propagates through thermodynamic models of the lead carbonate system and provide guidance for future modeling efforts. This was done by conducting a full factorial statistical analysis implemented using a custom Python (v3) code coupled with a PHREEQC (v1.4.2) geochemical model, along with batch lead solubility experiments. Two lead carbonate solid phases (cerussite and hydrocerussite) and nine aqueous lead complexes are considered in the geochemical model with conditions simulated ranging from pH 4 to 11 and dissolved inorganic carbon (DIC) ranging from 0 to 250 mg C/L. Main effect analysis indicates that model uncertainty is predominately associated with logK values for five species (in order of decreasing effect): hydrocerussite, , cerussite, PbOH+, and PbCO3o, with model uncertainty varying depending on the specific pH and DIC conditions simulated. Interaction effects show that logK values cannot be selected independently, as their influence on lead solubility is connected. Finally, by considering uncertainty in logK values it was possible for the thermodynamic model to match batch hydrocerussite solubility experimental data over a range of pH and DIC conditions. Six combinations of logK values that provided a good match between the simulated and experimental data were determined with the average difference between the simulated and experimental lead concentrations calculated to be 0.031 mg/L when the recommended logK value combination was used. HIGHLIGHTS Thermodynamic model uncertainty is predominately associated with logK values for five species (in order of decreasing effect): hydrocerussite, , cerussite, PbOH+, and PbCO3o.; LogK values for species cannot be selected independently, as their influence on lead solubility is interconnected.; Thermodynamic model uncertainty varies depending on specific pH and dissolved inorganic carbon conditions simulated.;C. KushnirC. E. RobinsonIWA Publishingarticlecerussitedrinking waterhydrocerussiteleadthermodynamic modeluncertaintyEnvironmental technology. Sanitary engineeringTD1-1066ENWater Quality Research Journal, Vol 56, Iss 4, Pp 194-204 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cerussite drinking water hydrocerussite lead thermodynamic model uncertainty Environmental technology. Sanitary engineering TD1-1066
spellingShingle	cerussite drinking water hydrocerussite lead thermodynamic model uncertainty Environmental technology. Sanitary engineering TD1-1066 C. Kushnir C. E. Robinson Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
description	Thermodynamic models of the lead carbonate aqueous system have been used in prior studies to evaluate the effect of water chemistry on lead solubility and corrosion scale composition in water distribution systems. A common challenge in these studies is uncertainty arising from the thermodynamic equilibrium constants (logK values) used to parameterize the models. The objective of this study is to evaluate the way in which uncertainty in logK values propagates through thermodynamic models of the lead carbonate system and provide guidance for future modeling efforts. This was done by conducting a full factorial statistical analysis implemented using a custom Python (v3) code coupled with a PHREEQC (v1.4.2) geochemical model, along with batch lead solubility experiments. Two lead carbonate solid phases (cerussite and hydrocerussite) and nine aqueous lead complexes are considered in the geochemical model with conditions simulated ranging from pH 4 to 11 and dissolved inorganic carbon (DIC) ranging from 0 to 250 mg C/L. Main effect analysis indicates that model uncertainty is predominately associated with logK values for five species (in order of decreasing effect): hydrocerussite, , cerussite, PbOH+, and PbCO3o, with model uncertainty varying depending on the specific pH and DIC conditions simulated. Interaction effects show that logK values cannot be selected independently, as their influence on lead solubility is connected. Finally, by considering uncertainty in logK values it was possible for the thermodynamic model to match batch hydrocerussite solubility experimental data over a range of pH and DIC conditions. Six combinations of logK values that provided a good match between the simulated and experimental data were determined with the average difference between the simulated and experimental lead concentrations calculated to be 0.031 mg/L when the recommended logK value combination was used. HIGHLIGHTS Thermodynamic model uncertainty is predominately associated with logK values for five species (in order of decreasing effect): hydrocerussite, , cerussite, PbOH+, and PbCO3o.; LogK values for species cannot be selected independently, as their influence on lead solubility is interconnected.; Thermodynamic model uncertainty varies depending on specific pH and dissolved inorganic carbon conditions simulated.;
format	article
author	C. Kushnir C. E. Robinson
author_facet	C. Kushnir C. E. Robinson
author_sort	C. Kushnir
title	Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
title_short	Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
title_full	Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
title_fullStr	Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
title_full_unstemmed	Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
title_sort	exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/6531be751e934bc493614a49c3089e7f
work_keys_str_mv	AT ckushnir exploringuncertaintyinthermodynamicmodelingoftheleadcarbonateaqueoussystem AT cerobinson exploringuncertaintyinthermodynamicmodelingoftheleadcarbonateaqueoussystem
_version_	1718399158939811840

Exploring uncertainty in thermodynamic modeling of the lead carbonate aqueous system

Ejemplares similares