Oxide surfaces develop a charge in H2O. Do we have any, even vague, handle on how long does an indivdual charge last on avg. before being neutralised?
Proton transfer reactions in water such as the ones you wrote down are diffusion controlled under ambient conditions (rate constant about 1e+12 per sec.) A snapshot in time will have a certain distribution of charges on the surface, but these are continually in flux, so any one charged site will have an exceedingly short lifetime. You could reasonably represent that system with a fixed set of charges on the surface, for some types of models (e.g., states at equilibrium).