The reductive dissolution of Fe-oxide driven by organic matter oxidation is the primary mechanism accepted for As mobilization in several alluvial aquifers. These processes are often mediated by microorganisms that require a minimum Gibbs energy available to conduct the reaction in order to sustain their life functions. Implementing this threshold energy in reactive transport modeling is rarely used in the existing literature. This work presents a 1D reactive transport modeling of As mobilization by the reductive dissolution of Fe-oxide and subsequent immobilization by co-precipitation in iron sulfides considering a threshold energy for the following terminal electron accepting processes: (a) Fe-oxide reduction, (b) sulfate reduction, and (c) methanogenesis. The model is then extended by implementing a threshold energy on both reaction directions for the redox reaction pairs Fe(III) reduction/Fe(II) oxidation and methanogenesis/methane oxidation. The optimal threshold energy fitted in 4.50, 3.76, and 1.60 kJ/mol e- for sulfate reduction, Fe(III) reduction/Fe(II) oxidation, and methanogenesis/methane oxidation, respectively. The use of models implementing bidirectional threshold energy is needed when a redox reaction pair can be transported between domains with different redox potentials. This may often occur in 2D or 3D simulations.

Rotiroti, M., Jakobsen, R., Fumagalli, M., Bonomi, T. (2018). Considering a threshold energy in reactive transport modeling of microbially mediated redox reactions in an arsenic-affected aquifer. WATER, 10(1) [10.3390/w10010090].

Considering a threshold energy in reactive transport modeling of microbially mediated redox reactions in an arsenic-affected aquifer

Rotiroti, M
Primo
;
Fumagalli, ML
Penultimo
;
Bonomi, T.
Ultimo
2018

Abstract

The reductive dissolution of Fe-oxide driven by organic matter oxidation is the primary mechanism accepted for As mobilization in several alluvial aquifers. These processes are often mediated by microorganisms that require a minimum Gibbs energy available to conduct the reaction in order to sustain their life functions. Implementing this threshold energy in reactive transport modeling is rarely used in the existing literature. This work presents a 1D reactive transport modeling of As mobilization by the reductive dissolution of Fe-oxide and subsequent immobilization by co-precipitation in iron sulfides considering a threshold energy for the following terminal electron accepting processes: (a) Fe-oxide reduction, (b) sulfate reduction, and (c) methanogenesis. The model is then extended by implementing a threshold energy on both reaction directions for the redox reaction pairs Fe(III) reduction/Fe(II) oxidation and methanogenesis/methane oxidation. The optimal threshold energy fitted in 4.50, 3.76, and 1.60 kJ/mol e- for sulfate reduction, Fe(III) reduction/Fe(II) oxidation, and methanogenesis/methane oxidation, respectively. The use of models implementing bidirectional threshold energy is needed when a redox reaction pair can be transported between domains with different redox potentials. This may often occur in 2D or 3D simulations.
Articolo in rivista - Articolo scientifico
Bacteria; Energy gap; Extended partial equilibrium approach; Fe-oxide reduction; Groundwater; Methanogenesis; Minimum Gibbs energy; Po plain; Sulfate reduction;
English
2018
10
1
90
open
Rotiroti, M., Jakobsen, R., Fumagalli, M., Bonomi, T. (2018). Considering a threshold energy in reactive transport modeling of microbially mediated redox reactions in an arsenic-affected aquifer. WATER, 10(1) [10.3390/w10010090].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/181530
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