No ice on the moon?

Exchange Reactions at Mineral Interfaces

Exchange reactions are a family of chemical reactions that appear when mineral surfaces come into contact with protic solvents. Exchange reactions can also be understood as a unique interaction at mineral interfaces. Particularly significant interactions occurring at mineral surfaces are those with water and CO₂. The rather complex process occurring when minerals such as calcium silicate hydrate (C-S-H) phases come into contact with aqueous environments is referred to as a metal-proton exchange reaction (MPER). This process leads to the leaching of calcium ions from the near-surface region, the first step in the corrosion of cement-bound materials. Among the various corrosion reactions of C-S-H phases, the MPER appears to be the most important one. A promising approach to bridging certain problems caused by MPER and carbonation is the passivation of C-S-H surfaces. Today, such passivation is reached, for instance, by the functionalization of C-S-H surfaces with water-repelling organic films. Unfortunately, these organic films are weak against temperature and especially weak against abrasion. Exchange reactions at mineral interfaces allow the preparation of intrinsic, hydrophobic surfaces of C-S-H phases just at room temperature via a metal-metal exchange reaction.