Water-induced rearrangement of Ca(OH)2 (0001) surfaces reacted with SO2

AFM imaging and EDS microanalyses provide evidence of the reorganization of single-crystal Ca(OH)(2) (0001) surfaces attacked by SO2 at low temperature when exposed to water vapor in such a way that larger product features are formed from the aggregation of smaller ones. This product rearrangement induced by water vapor might provide a new accessible Ca(OH)(2) surface for further reaction with SO2, which might account for the general observation reported in the literature that water vapor exerts a substantial influence on the ability of commercial hydrated lime to retain SO2 in flue gas desulfurization (FGD) technologies. A reaction mechanism consistent with the experimental observations and with its kinetic implications is discussed. (c) 2006 American Institute of Chemical