ABSTRACT
Natural rocks and soils are usually complex, multicomponent systems. Besides this inherent complexity, the geological and environmental conditions that they are subjected to may also be very diverse. As a result, the interfacial reactions are complicated, and are strongly dependent on the substances present and environmental conditions. Therefore, studies of interfacial processes of rocks and soils may have different scopes and objectives. First, there are studies that aim to understand the underlying principles behind the reactions. For these, the natural samples in their original forms are mostly not suitable because, due to the great number of components and other factors, the results obtained are difficult to interpret. For example, the components and factors may mask the effect of one another. So, these studies require the use of model substances and conditions that are representative but somewhat simplified to those in natural samples and that enable us to concentrate on the characteristic properties and to avoid disturbing effects. It is important to note that, depending on the objective of the study, the model substance must mimic the original sample as much as possible. Some authors use very pure model substances and strict experimental conditions that vary the parameters in very narrow ranges. As a result, the data obtained in these experiments cannot be adequately used for natural rock and soil systems.
