Illite spatial distribution patterns dictates Cr(VI) sorption macrocapacity and macrokinetic

This data set examines the largely unexplored role of illite spatial distribution patterns in dictating sorption of Cr(VI). Flow-through experiments were carried out at 0.6, 3.0 and 15.0 m/day using columns packed with the same illite and quartz mass however with different patterns and permeability contrasts. Column-scale sorption macrocapacity and macrorates were found to decrease with transport connectivity, a quantitative measure of heterogeneity characteristics. At 0.6 and 3.0 m/day, well-connected low permeability illite zones oriented in the flow-parallel direction leads to diffusion-controlled mass transport limitation to access sorption sites, leading to up to 1.4 order of magnitude lower macrocapacity and macrorates compared to those in minimally-connected columns with well-mixed illite and quartz. Insights gained here bridge gaps between laboratory and field application, advance predictive understanding of reactive transport processes in natural heterogeneous subsurface.