Insights into the weathering behavior of pyrite in alkaline soil through electrochemical characterizations: Actual hazards or potentially benefits?

Feng, X; Chen, Z; Wang, S; Cen, L; Ni, B-J; Liu, Q

Insights into the weathering behavior of pyrite in alkaline soil through electrochemical characterizations: Actual hazards or potentially benefits?

Feng, X Chen, Z

Wang, S Cen, L Ni, B-J Liu, Q

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Publisher:: Elsevier
Publication Type:: Journal Article
Citation:: J Hazard Mater, 2023, 451, pp. 131145
Issue Date:: 2023-03-05

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Field	Value	Language
dc.contributor.author	Feng, X
dc.contributor.author	Chen, Z https://orcid.org/0000-0003-0627-0856
dc.contributor.author	Wang, S
dc.contributor.author	Cen, L
dc.contributor.author	Ni, B-J
dc.contributor.author	Liu, Q
dc.date.accessioned	2023-03-22T02:35:38Z
dc.date.available	2023-03-02
dc.date.available	2023-03-22T02:35:38Z
dc.date.issued	2023-03-05
dc.identifier.citation	J Hazard Mater, 2023, 451, pp. 131145
dc.identifier.issn	0304-3894
dc.identifier.issn	1873-3336
dc.identifier.uri	http://hdl.handle.net/10453/168043
dc.description.abstract	Pyrite is the most common metal sulfide mineral in the crust and readily weathers under natural circumstances to release H+ to acidify surrounding groundwater and soil, resulting in heavy metal ions in the surrounding environment (e.g., meadow and saline soils). Meadow and saline soils are two common, widely distributed alkaline soils and can affect pyrite weathering. Currently, the weathering behaviors of pyrite in saline and meadow soil solutions have not been systematically studied. Electrochemistry coupled with surface analysis methods were employed to study pyrite weathering behaviors in simulated saline and meadow soil solutions in this work. Experimental results suggest that saline soil and higher temperatures increase pyrite weathering rates due to the lower resistance and greater capacitance. Surface reactions and diffusion control the weathering kinetics, and the activation energies for the simulated meadow and saline soil solutions are 27.1 and 15.8 kJ mol-1, respectively. In-depth investigations reveal that pyrite is initially oxidized to Fe(OH)3 and S0, and Fe(OH)3 further transforms into goethite γ-FeOOH and hematite α-Fe2O3, while S0 ultimately converts into sulfate. When these iron compounds enter alkaline soils, the alkalinity of soil changes, and iron (hydr)oxides effectively reduce the bioavailability of heavy metals and benefit alkaline soils. Meanwhile, weathering of natural pyrite ores containing toxic elements (such as Cr, As, and Cd) makes these elements bioavailable and potentially degrades the surrounding environment.
dc.format	Print-Electronic
dc.language	eng
dc.publisher	Elsevier
dc.relation.ispartof	J Hazard Mater
dc.relation.isbasedon	10.1016/j.jhazmat.2023.131145
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	03 Chemical Sciences, 05 Environmental Sciences, 09 Engineering
dc.subject.classification	Strategic, Defence & Security Studies
dc.title	Insights into the weathering behavior of pyrite in alkaline soil through electrochemical characterizations: Actual hazards or potentially benefits?
dc.type	Journal Article
utslib.citation.volume	451
utslib.location.activity	Netherlands
utslib.for	03 Chemical Sciences
utslib.for	05 Environmental Sciences
utslib.for	09 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
pubs.organisational-group	/University of Technology Sydney/Strength - CTWW - Centre for Technology in Water and Wastewater Treatment
utslib.copyright.status	closed_access	*
dc.date.updated	2023-03-22T02:35:25Z
pubs.publication-status	Published online
pubs.volume	451

Abstract:

Pyrite is the most common metal sulfide mineral in the crust and readily weathers under natural circumstances to release H+ to acidify surrounding groundwater and soil, resulting in heavy metal ions in the surrounding environment (e.g., meadow and saline soils). Meadow and saline soils are two common, widely distributed alkaline soils and can affect pyrite weathering. Currently, the weathering behaviors of pyrite in saline and meadow soil solutions have not been systematically studied. Electrochemistry coupled with surface analysis methods were employed to study pyrite weathering behaviors in simulated saline and meadow soil solutions in this work. Experimental results suggest that saline soil and higher temperatures increase pyrite weathering rates due to the lower resistance and greater capacitance. Surface reactions and diffusion control the weathering kinetics, and the activation energies for the simulated meadow and saline soil solutions are 27.1 and 15.8 kJ mol-1, respectively. In-depth investigations reveal that pyrite is initially oxidized to Fe(OH)3 and S0, and Fe(OH)3 further transforms into goethite γ-FeOOH and hematite α-Fe2O3, while S0 ultimately converts into sulfate. When these iron compounds enter alkaline soils, the alkalinity of soil changes, and iron (hydr)oxides effectively reduce the bioavailability of heavy metals and benefit alkaline soils. Meanwhile, weathering of natural pyrite ores containing toxic elements (such as Cr, As, and Cd) makes these elements bioavailable and potentially degrades the surrounding environment.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/168043