Dissolution crystal formation modeling

The geochemical fate of most reactive substances (trace metals, pollutants) is controlled by the reaction of solutes with solid surfaces. Simple chemical models for the residence time of reactive elements in oceans, lakes, sediment, and soil systems are based on the partitioning of chemical species between the aqueous solution and the particle surface. The rates of processes involved in precipitation (heterogeneous nucleation, crystal growth) and dissolution of mineral phases, of importance in the weathering of rocks, in the formation of soils, and sediment diagenesis, are critically dependent on surface species and their structural identity. 

Unfortunately nephrolithiasis is a recirrrent disease and about 75% of patients suffer the recurrence within 10 years. Therefore it is important to develop new more efficient preventative therapies, which can inhibit the formation of kidney stones or possess properties of dissolution of calciitm oxalate deposits. The possible approach constitutes modeling the potential inhibitors forming calcium oxalate crystals. On the other hand there are available compoimds directly influencing the calciiun oxalate formation (inhibitory or dissolution effect) e.g. citrate. It should be noted that compounds possessing dissolution properties of calcimn oxalate carmot interfere too much into the whole calcimn economy. 

On solid metals the situation for ion deposition or dissolution in electrode reactions is much more complicated. The models for crystal growth from the vapor phase or atomic evaporation have to be applied, being modified by ion discharge or ion formation in passing the electrical double layer at the interface. Figure 2.31 represents the main positions of atoms on the surface of a low index face of a metal with one monoatomic step. It is assumed that the edge of the step is not smooth and contains several kink sites. 

A very old but still widely accepted model for the dissolution of a crystal [2] involves two steps the detachment of molecules from the crystal with the formation of a saturated layer of thickness h near the solid surface, followed by diffusion of solute molecules from this layer into the bulk solution. The formation of the saturated layer, with competition between detachment of molecules from the crystal surface and re-adsorption onto it, is the structure-sensitive step it depends on crystal structure overall, on macroscopic crystal morphology, and on the number and type of... 

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