Kinetic Accessibility of Porous Material Adsorption Sites Studied through the Lattice Boltzmann Method

Abstract

We present here a computational model based on the lattice Boltzmann scheme to investigate the accessibility of active adsorption sites in hierarchical porous materials to adsorbates in a flowing liquid. By studying the transport and adsorption of tracers after they enter the pore space of the virtual sample, we characterize their kinetics as they pass through the pore space and adsorb on the solid-liquid interface. The model is validated on simple geometries with a known analytical solution. We then use it to investigate the influence of regular grooves or disordered roughness on the walls of a slit pore geometry, looking at the impact on adsorption and transport. In particular, we highlight the importance of adsorption site accessibility, which depends on the shape and connectivity of the pore space as well as the fluid flow profile and velocity.

The chemical continuous time random walk framework for upscaling transport limitations in fluid–solid reactions

“…This phenomenon has been observed in resolved numerical simulations of carbonate mineral dissolution in porous media [8], numerical simulation and column experiments of calcite dissolution [9,21,22], numerical simulations of mineral dissolution in heterogeneous porous media [11,23], pore-scale reactive transport simulations in rough fractures [13], and batch experiments and field-scale modeling of biodegradation of dissolved organic carbon in aquifers [24]. Pore-scale flow and structure have also been found to significantly impact adsorption to mineral surfaces in porous media, an effect which has been observed in detailed lattice-Boltzmann simulations [16][17][18].…”

Lattice Boltzmann method for adsorption under stationary and transient conditions: Interplay between transport and adsorption kinetics in porous media

“…While fluid transport and dispersion in restricted geometries such as in porous media have been broadly considered in physics, the impact of fluid transport on adsorption phenomena remains puzzling by many aspects [1][2][3][4][5][6][7][8][9]. Situations corresponding to a flowing liquid (solvent) carrying adsorbable molecules (solute) in a porous material have been treated extensively under static conditions (stationary regime) [10,11].…”

“…Besides the different adsorption/transport regimes, the porous medium structure is another ingredient that significantly influences the transport behavior of adsorbing molecules (since adsorption is also sensitive to the geometry/structure of the solid/fluid interface) [12][13][14]. In particular, depending on the porous structure, features such as constrictions or low porosity zones (reduced flow) induce strong coupling between fluid transport and molecular adsorption [9,15,16]. Therefore, understanding the interplay between the structural heterogeneity of the porous medium and the adsorption thermodynamics and kinetics is considered as a key fundamental challenge [17,18].…”

Moment propagation method for the dynamics of charged adsorbing/desorbing species at solid-liquid interfaces

“…Several descriptions and extensions of this method have since been proposed for various applications, see e.g. [33,35,36,[43][44][45][46]. In the present work, we show that this method can be used for charged mobile (hence experiencing diffusion, advection and migration) and adsorbing/desorbing species -a combination of features which had to date not been investigated previously despite its relevance in the many contexts described in the introduction.…”