Coulombic interactions between charged species in pore water and at surface/solution interfaces are of pivotal importance for multicomponent reactive transport in porous media. In this study, we investigate the impact of domain dimensionality on electrostatically coupled dispersion and surface-solution reactions during transport of acidic plumes and major ions in porous media.

Column and quasi two-dimensional flow-through experiments were performed, with identical silica porous media and under the same advection-dominated conditions. Equal mass fluxes of different electrolyte solutions (i.e., HCl - pH ∼ 2.8, NaBr - 100 mM, HCl - pH ∼ 2.8 plus NaBr - 100 mM) were continuously injected in the 1-D and 2-D experiments and breakthrough curves of pH and major ions were measured at the outlet of the domains. The presence of pronounced ionic strength gradients in the transverse direction in the 2-D setup caused distinct retardation and transport behaviors of protons and major ions which were not observed in the one-dimensional column experiments. Furthermore, in the cases of salt electrolytes injection, considerably enhanced release of H⁺ (>61%) from the quartz surface was observed in the multidimensional system compared to the one-dimensional setup.

Reactive transport modeling was performed to reproduce the experimental outcomes and to analyse the coupling between transport processes, based on the Nernst-Planck formulation of diffusive/dispersive fluxes and on surface complexation reactions at the solid-solution interface. Electrostatic interactions between Na⁺, Br⁻, and H⁺, and deprotonation of the quartz surface upon the formation of sodium outer-sphere complexes, are the primary controllers of the spatial and temporal features displayed by the pH and major ions measurements. The reactive transport simulations allowed us to interpret the experimental observations, to visualize the distribution and spatio-temporal evolution of dissolved and solid species, to identify a spatially heterogeneous zonation of Coulombic interactions with distinct behavior at the fringe and core of the injected plumes in the multidimensional setup, and to quantify the different components of the Nerst-Planck fluxes of the charged solutes. This study demonstrates that the domain dimensionality directly affects electrostatic interactions between charged aqueous species in the pore water and surface complexation reactions at the solid-solution interface. The non-trivial effects of dimensionality on multicomponent ionic transport result in a significantly different behavior in 1-D and 2-D systems.

孔隙水中带电物质与表面/溶液界面之间的库仑相互作用对于多孔介质中的多组分反应传输至关重要。在这项研究中，我们研究了在多孔介质中酸性羽流和主要离子传输过程中域维数对静电耦合分散和表面-溶液反应的影响。

使用相同的二氧化硅多孔介质和相同的平流主导条件进行柱和准二维流通实验。在一维和二维实验中连续注入不同电解质溶液（即 HCl - pH ∼ 2.8、NaBr - 100 mM、HCl - pH ∼ 2.8 加 NaBr - 100 mM）的相同质量通量和 pH 的突破曲线和主要离子在域的出口处测量。二维设置中横向存在明显的离子强度梯度导致质子和主要离子的明显延迟和传输行为，而这些在一维柱实验中未观察到。此外，在注入盐电解质的情况下，H ^{+ 的}释放显着增加 与一维设置相比，在多维系统中观察到来自石英表面的 (>61%)。

基于扩散/色散通量的 Nernst-Planck 公式和固溶体界面的表面络合反应，进行了反应输运建模以重现实验结果并分析输运过程之间的耦合。Na ⁺、Br ^-和 H ⁺之间的静电相互作用和石英表面在钠外球络合物形成时的去质子化是 pH 值和主要离子测量显示的空间和时间特征的主要控制者。反应输运模拟使我们能够解释实验观察结果，可视化溶解和固体物质的分布和时空演化，识别库仑相互作用的空间异质区带，在注入羽流的边缘和核心处具有不同的行为。多维设置，并量化带电溶质的 Nerst-Planck 通量的不同成分。该研究表明，域维数直接影响孔隙水中带电水性物质与固溶体界面的表面络合反应之间的静电相互作用。维度对多组分离子传输的重要影响导致一维和二维系统中的显着不同行为。