Assessing the effect of dissolved organic ligands on mineral dissolution rates: an example from calcite dissolution

摘要

Experiments suggest that dissolved organic ligands may primarily modify mineral dissolution rates by three mechanisms: (1) metal-ligand (M-L) complex formation in solution, which increases the degree of undersaturation, (2) formation of surface M-L complexes that attack the surface, and (3) formation of surface complexes which passivate or "protect" the surface. Mechanisms (1) and (2) increase the dissolution rate the third decreases it compared with organic-free solutions. The types and importance of these mechanisms may be assessed from plots of dissolution rate versus degree of undersaturation.