Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling

Abstract The dissolution of sulfide minerals in subsurface porous media has important environmental implications. We investigate the oxidative dissolution of pyrite under evaporative conditions and advance a mechanistic understanding of the interactions between multiple physical processes and minera...

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Main Authors: Navid Ahmadi, Muhammad Muniruzzaman, Jacopo Cogorno, Massimo Rolle
Format: Article
Language:English
Published: Wiley 2025-01-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2024WR037317
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author Navid Ahmadi
Muhammad Muniruzzaman
Jacopo Cogorno
Massimo Rolle
author_facet Navid Ahmadi
Muhammad Muniruzzaman
Jacopo Cogorno
Massimo Rolle
author_sort Navid Ahmadi
collection DOAJ
description Abstract The dissolution of sulfide minerals in subsurface porous media has important environmental implications. We investigate the oxidative dissolution of pyrite under evaporative conditions and advance a mechanistic understanding of the interactions between multiple physical processes and mineral/surface reactions. We performed a set of experiments in which initially water saturated and anoxic soil columns, containing a top layer of pyrite, are exposed to the atmosphere under no evaporation (single‐phase) and natural evaporative (two‐phase) conditions. The oxidative dissolution of pyrite was monitored by non‐invasive high‐resolution measurements of oxygen and pH. Additionally, we developed and applied a multiphase and multicomponent reactive transport model to quantitatively describe the experimental outcomes and elucidate the interplay between the physico‐chemical mechanisms controlling the extent of pyrite dissolution. The results confirm that the extent of pyrite dissolution under single‐phase conditions was constrained by the slow diffusive transport of oxygen in the liquid phase. In contrast, during evaporation, the evolution of fluid phases and interphase mass transfer processes imposed distinct physical constraints on the dynamics of pyrite oxidation. Initially, the invasion of the gaseous phase led to a fast delivery of high oxygen concentrations in the reactive zone and thus markedly increased pyrite oxidation and acidity/sulfate production. However, such enhanced release of reaction products was progressively limited over time as drying conditions prevailed in the reactive zone and inhibited pyrite oxidation. The transient phase displacement was also found to control the distribution of aqueous species and formation of secondary minerals by creating spatio‐temporally variable redox conditions.
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spelling doaj-art-21d2e8d3b84d4e04970b59fc3a80c6e62025-08-20T02:36:42ZengWileyWater Resources Research0043-13971944-79732025-01-01611n/an/a10.1029/2024WR037317Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based ModelingNavid Ahmadi0Muhammad Muniruzzaman1Jacopo Cogorno2Massimo Rolle3Institute of Applied Geosciences Technical University of Darmstadt Darmstadt GermanyWater Management Geological Survey of Finland Espoo FinlandDepartment of Environmental and Resource Engineering Technical University of Denmark Lyngby DenmarkInstitute of Applied Geosciences Technical University of Darmstadt Darmstadt GermanyAbstract The dissolution of sulfide minerals in subsurface porous media has important environmental implications. We investigate the oxidative dissolution of pyrite under evaporative conditions and advance a mechanistic understanding of the interactions between multiple physical processes and mineral/surface reactions. We performed a set of experiments in which initially water saturated and anoxic soil columns, containing a top layer of pyrite, are exposed to the atmosphere under no evaporation (single‐phase) and natural evaporative (two‐phase) conditions. The oxidative dissolution of pyrite was monitored by non‐invasive high‐resolution measurements of oxygen and pH. Additionally, we developed and applied a multiphase and multicomponent reactive transport model to quantitatively describe the experimental outcomes and elucidate the interplay between the physico‐chemical mechanisms controlling the extent of pyrite dissolution. The results confirm that the extent of pyrite dissolution under single‐phase conditions was constrained by the slow diffusive transport of oxygen in the liquid phase. In contrast, during evaporation, the evolution of fluid phases and interphase mass transfer processes imposed distinct physical constraints on the dynamics of pyrite oxidation. Initially, the invasion of the gaseous phase led to a fast delivery of high oxygen concentrations in the reactive zone and thus markedly increased pyrite oxidation and acidity/sulfate production. However, such enhanced release of reaction products was progressively limited over time as drying conditions prevailed in the reactive zone and inhibited pyrite oxidation. The transient phase displacement was also found to control the distribution of aqueous species and formation of secondary minerals by creating spatio‐temporally variable redox conditions.https://doi.org/10.1029/2024WR037317soil/atmosphere interactionsevaporative dryingmultiphase flowsulfide mineral dissolutionmulticomponent reactive transportgeochemical reactions
spellingShingle Navid Ahmadi
Muhammad Muniruzzaman
Jacopo Cogorno
Massimo Rolle
Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling
Water Resources Research
soil/atmosphere interactions
evaporative drying
multiphase flow
sulfide mineral dissolution
multicomponent reactive transport
geochemical reactions
title Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling
title_full Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling
title_fullStr Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling
title_full_unstemmed Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling
title_short Oxidative Dissolution of Sulfide Minerals in Porous Media Under Evaporative Conditions: Multiphase Experiments and Process‐Based Modeling
title_sort oxidative dissolution of sulfide minerals in porous media under evaporative conditions multiphase experiments and process based modeling
topic soil/atmosphere interactions
evaporative drying
multiphase flow
sulfide mineral dissolution
multicomponent reactive transport
geochemical reactions
url https://doi.org/10.1029/2024WR037317
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AT muhammadmuniruzzaman oxidativedissolutionofsulfidemineralsinporousmediaunderevaporativeconditionsmultiphaseexperimentsandprocessbasedmodeling
AT jacopocogorno oxidativedissolutionofsulfidemineralsinporousmediaunderevaporativeconditionsmultiphaseexperimentsandprocessbasedmodeling
AT massimorolle oxidativedissolutionofsulfidemineralsinporousmediaunderevaporativeconditionsmultiphaseexperimentsandprocessbasedmodeling