oa Ab initio study of the reactivity of edge sites of phyllosilicate clays

Natural waters, permeability reduction in reservoir rocks, groundwater flow and clay rheology [1]. In addition, pyrophyllite clays have a number of industrial applications due to their distinctive surface chemical properties. The edge sites play an important role for pH dependent sorption of ions from solutions of electrolytes. For a full understanding of pyrophyllite formation and properties, a study of the chemistry of the system, the dynamical interactions between the components and the mesostructure are necessary. While experimentally it is difficult to determine the structure of these clays due to their disordered nature, molecular computer simulation has become an extremely useful, if not essential, tool for understanding the underlying principals behind surface chemistry [2,3]. As each property is associated with separate time and length scale, multiscale approaches such as DFT Molecular dynamics MD, classical molecular dynamics and Coarse Grained molecular dynamics are needed. In this talk, we will present a first principles molecular dynamics FPMD studies on hydrated Phyrophyllite clays which is the simplest structural prototype for 2:1 dioctahedral phyllosilicates. Octahedral (Mg for Al) and tetrahedral (Al for Si) substitutions allowing to a charged structure named Montmorollonite are also presented in this study.