Impact of Barium and Cadmium on Defluoridation by Calcite: Batch Reactor and Column Tests

Cai, Q; Turner, BD; Sheng, D; Sloan, S

Impact of Barium and Cadmium on Defluoridation by Calcite: Batch Reactor and Column Tests

Cai, Q Turner, BD Sheng, D

Sloan, S

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Publisher:: Mary Ann Liebert
Publication Type:: Journal Article
Citation:: Environmental Engineering Science, 2017, 34, (11), pp. 792-804
Issue Date:: 2017-11-01

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Field	Value	Language
dc.contributor.author	Cai, Q
dc.contributor.author	Turner, BD
dc.contributor.author	Sheng, D https://orcid.org/0000-0002-1665-6931
dc.contributor.author	Sloan, S
dc.date.accessioned	2022-08-25T23:25:20Z
dc.date.available	2022-08-25T23:25:20Z
dc.date.issued	2017-11-01
dc.identifier.citation	Environmental Engineering Science, 2017, 34, (11), pp. 792-804
dc.identifier.issn	1092-8758
dc.identifier.issn	1557-9018
dc.identifier.uri	http://hdl.handle.net/10453/160879
dc.description.abstract	This study focuses on the investigation regarding impact of Ba2+ and Cd2+ on defluoridation by calcite because Spent Pot Lining (SPL, a byproduct generated during the aluminum production) leachate is a complex chemical cocktail. To better understand defluoridation processes and replicate the situation in the field, column tests were conducted. Results indicate that presence of neither Ba2+ nor Cd2+ has significant impact on fluoride retention when compared with the blank (no metals) because the relative concentration values (F/Fo) as well as the transport parameters like retardation factor (Rc) and distribution coefficient (Kd) are almost the same. PHREEQC, a geochemical software, was then applied to simulate the column test processes (i.e., 1D reactive/transport processes) based on the mechanism of CaF2 precipitation followed after calcium dissolution. As indicated in the batch reactor test, addition of Cd2+ may inhibit calcite dissolution; therefore, a new phase "CalciteSupp" (a phase representing the suppressed solubility of calcite) was defined. Modeling results exhibit good predictions of observed data, and the log-k solubility of the hypothetical "CalciteSupp" equilibrium phase implies the suppression of calcite dissolution in the metal samples. Moreover, saturation indices obtained by modeling indicate the precipitation of CdCO3 and BaCO3, revealing that addition of metals may influence fluoride removal at some point during the process, but has no big impact on overall defluoridation. The initial development of the PHREEQC geochemical model presented shows potential in being able to be used as a predictive tool for the design of fluoride remediation strategies, such as permeable reactive barriers, and transport parameters obtained on the basis of the column tests, and CXTFIT (a computer program for evaluating and estimating transport parameters) modeling can be applied in practical design.
dc.language	English
dc.publisher	Mary Ann Liebert
dc.relation.ispartof	Environmental Engineering Science
dc.relation.isbasedon	10.1089/ees.2017.0006
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	0502 Environmental Science and Management, 0904 Chemical Engineering, 0907 Environmental Engineering
dc.subject.classification	Environmental Engineering
dc.title	Impact of Barium and Cadmium on Defluoridation by Calcite: Batch Reactor and Column Tests
dc.type	Journal Article
utslib.citation.volume	34
utslib.for	0502 Environmental Science and Management
utslib.for	0904 Chemical Engineering
utslib.for	0907 Environmental Engineering
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
utslib.copyright.status	closed_access	*
pubs.consider-herdc	false
dc.date.updated	2022-08-25T23:25:19Z
pubs.issue	11
pubs.publication-status	Published
pubs.volume	34
utslib.citation.issue	11

Abstract:

This study focuses on the investigation regarding impact of Ba2+ and Cd2+ on defluoridation by calcite because Spent Pot Lining (SPL, a byproduct generated during the aluminum production) leachate is a complex chemical cocktail. To better understand defluoridation processes and replicate the situation in the field, column tests were conducted. Results indicate that presence of neither Ba2+ nor Cd2+ has significant impact on fluoride retention when compared with the blank (no metals) because the relative concentration values (F/Fo) as well as the transport parameters like retardation factor (Rc) and distribution coefficient (Kd) are almost the same. PHREEQC, a geochemical software, was then applied to simulate the column test processes (i.e., 1D reactive/transport processes) based on the mechanism of CaF2 precipitation followed after calcium dissolution. As indicated in the batch reactor test, addition of Cd2+ may inhibit calcite dissolution; therefore, a new phase "CalciteSupp" (a phase representing the suppressed solubility of calcite) was defined. Modeling results exhibit good predictions of observed data, and the log-k solubility of the hypothetical "CalciteSupp" equilibrium phase implies the suppression of calcite dissolution in the metal samples. Moreover, saturation indices obtained by modeling indicate the precipitation of CdCO3 and BaCO3, revealing that addition of metals may influence fluoride removal at some point during the process, but has no big impact on overall defluoridation. The initial development of the PHREEQC geochemical model presented shows potential in being able to be used as a predictive tool for the design of fluoride remediation strategies, such as permeable reactive barriers, and transport parameters obtained on the basis of the column tests, and CXTFIT (a computer program for evaluating and estimating transport parameters) modeling can be applied in practical design.

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http://hdl.handle.net/10453/160879