This presentation will discuss how the pore-scale process coupling in intragranular and intergranular domains affect the manifestation of hematite reduction rates at the continuum scale in subsurface sediments. Micromodels with complex pore-networks and with pore surfaces coated with hematite are used to investigate the rates of iron oxide reduction by quinone-type reductants. Both heterogeneous advective pore-networks and diffusion-dominated pore structures isolated from subsurface sediments are evaluated to determine their effect on the apparent rates of hematite reduction at the grain and continnum scales. The presentation will show both experimental and numerical results of hematite reduction at the pore-scale under well-mixed, diffusion-controlled, and heterogeneous flow conditions. The presentation will also show theoretical challenges to scale redox reaction rates from the molecular to the scale that can be used for reactive transport modeling at the field-scale, and will discuss approaches to scale redox reaction rates.

Effect of pore-scale process coupling on hematite reduction rates in subsurface porous media

243rd National Meeting (2012)

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