Atomic scale mechanism of clay minerals dissolution revealed by ab initio simulations

Large-scale ab initio Meta-Dynamics simulations were applied to elucidate the molecular mechanism and reaction free energies of pyrophyllite dissolution at (1 1 0) edge surface in pure water close neutral pH under far from equilibrium conditions. The simulation setup allows realistic representation clay mineral explicit consideration solvent dynamics finite temperature. reveals that a single tetrahedral or an octahedral unit is complex multi-step process with several intermediates. Typically, each step changes denticity reacting site step-by-step manner leads, eventually, leaching ions forming sheets phyllosilicate. rearrangement proton transfer reactions first second coordination shell dissolving play critical role stabilization intermediates net progress reactions. overall can be rationalized as sequence concurrent reversible elementary events, which are: (1) nucleophilic attack H 2 O molecules OH groups on site. (2) ligand exchange sites leading its conformation surface. (3) collective between acidic basic oxygen mediated via chain hydrogen bonded results obtained this study are general applicable group 2:1 phyllosilicates wide range chemical thermodynamic