Simulation of adsorption processes on the glass surface in aqueous solutions containing oxalic acid

In this this study we develop a kinetic model for the simulation of adsorption processes on a glass surface in the presence of oxalic acid, which is subsequently used for an investigation of strategies to inhibit glass corrosion by means of surface oxalate complexes. The behavior of individual adsorbing species is resolved by a Kinetic Monte Carlo method (KMC). Kinetic parameters for different process specifications were chosen from experimental data or were calculated ab initio by the density functional theory (DFT). Our simulations indicate that surface complexation occurs at pH < 8 for the Al containing glass and at pH < 6 for the diopside glass. Moreover it reveals, that on the one hand the surface protonation catalyses the surface complexation, which can inhibit the glass corrosion. On the other hand the formation of magnesium and aluminium surface complexes catalyses the proton-promoted dissolution. The overall effect leads to the inhibition of corrosion at pH values <5 for diopside glass due to formation of stable calcium-magnesium oxalate complexes. (C) 2010 Elsevier B.V. All rights reserved.