Long-term kinetics of uranyl desorption from sediments under advective conditions

Shang, Jianying; Liu, Chongxuan; Wang, Zheming; Zachara, John M.

doi:10.1002/2013wr013949

Cited by 16 publications

(14 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3) core scale numerical simulations with numerical grid size from centimeter to meters (Zinn and Harvey 2003;Shang et al 2011Shang et al , 2014Liu et al 2014a); and 4) pore-scale research at the scales of m to mm (Willingham et al 2008;Zhang et al 2013a). …”

Section: Theoretical Consideration Of Effective Reaction Ratesmentioning

confidence: 99%

Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

Liu

Kerisit

et al. 2015

Reviews in Mineralogy and Geochemistry

Self Cite

View full text Add to dashboard Cite

Section: Theoretical Consideration Of Effective Reaction Ratesmentioning

confidence: 99%

Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

Liu

Kerisit

et al. 2015

Reviews in Mineralogy and Geochemistry

Self Cite

View full text Add to dashboard Cite

“…5-8), which considers the subgrid heterogeneity by grouping pore regions with similar pore-scale reactive transport properties into three subgrid domains, was evaluated to scale the reactions in heterogeneous porous media from the pores to continuum scale. The triple domain model has been successfully used to scale uranyl surface complexation reactions from intragranular pore scale to sediment cores under flow conditions (Liu et al, 2008Shang et al, 2014). To apply the triple domain model, .…”

Section: Subgrid Domain-based Approach For Scaling Reactionsmentioning

confidence: 99%

Pore and continuum scale study of the effect of subgrid transport heterogeneity on redox reaction rates

Liu

Zhang

et al. 2015

Geochimica et Cosmochimica Acta

Self Cite

View full text Add to dashboard Cite

A micromodel system, which corresponds to one or part of a numerical grid in the continuum model, was used to investigate the effect of subgrid transport heterogeneity on redox reaction rates. Hematite reductive dissolution by injecting a reduced form of flavin mononucleotide (FMNH 2 ) at variable flow rates was used as an example to probe the variations of redox reaction rates in different subgrid transport domains. Experiments, pore-scale simulations, and macroscopic continuum modeling were performed to measure and simulate in-situ hematite reduction and to evaluate the scaling behavior of the redox reaction rates from the pore to continuum scales. The results indicated that the measured pore-scale rates of hematite reduction were consistent with the predictions from a pore-scale reactive transport model. A general trend is that hematite reduction followed reductant transport pathways, starting from the advection-dominated pores toward the interior of diffusion-dominated domains. Two types of diffusion domains were considered in the micromodel: a micropore diffusion domain, which locates inside solid grains or aggregates where reactant transport is limited by diffusion; and a macropore diffusion domain, which locates at wedged, dead-end pore spaces created by the grain-grain contacts. The rate of hematite reduction in the advection-dominated domain was faster than those in the diffusion-controlled domains, and the rate in the macropore diffusion domain was faster than that in the micropore domain. The reduction rates in the advection and macropore diffusion domains increased with increasing flow rate, but were affected by different mechanisms. The rate increase in the advection domain was controlled by the mass action effect as a faster flow supplied more reactants, and the rate increase in the macropore domain was more affected by the rate of mass exchange with the advection domain, which increased with increasing flow rate. The hematite reduction rate in the micropore domain was, however, not affected by the flow rate because molecular diffusion limits reductant supply to the micropore domain interior. Domain-based macroscopic models were evaluated to scale redox reaction rates from the pore to continuum scales. Simulation results from the single domain model, which ignores subgrid transport heterogeneity, deviated significantly from the pore-scale results. Further analysis revealed that the rate expression for hematite reduction was not scalable from the pore to porous media using the single domain model. A three-domain model, which effectively considers subgrid reactive diffusion in the micropore and macropore domains, significantly improved model description. Overall this study revealed the importance of subgrid transport heterogeneity in the manifestation of redox reaction rates in porous media and in scaling reactions from the pore to porous media. The research also supported that the domain-based scaling approach can be used to directly scale redox reactions in porous media with subgrid transport hetero...

show abstract

“…3) core scale numerical simulations with numerical grid size from centimeter to meters (Zinn and Harvey 2003;Shang et al 2011Shang et al , 2014Liu et al 2014a); and 4) pore-scale research at the scales of Pm to mm (Willingham et al 2008;Zhang et al 2013a).…”

Section: Theoretical Consideration Of Effective Reaction Ratesmentioning

confidence: 99%

6. Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

Liu¹,

Liu²,

Kerisit³

et al. 2015

Pore Scale Geochemical Processes

Self Cite

View full text Add to dashboard Cite

show abstract

Long-term kinetics of uranyl desorption from sediments under advective conditions

Cited by 16 publications

References 25 publications

Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

Pore and continuum scale study of the effect of subgrid transport heterogeneity on redox reaction rates

6. Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials

Contact Info

Product

Resources

About