Mineralogical, crystal structural and crystal chemical aspects of the sortpion properties of smectites.

Transformation of clay minerals (mainly in soils) and the effect of the alteration of clay minerals on the physical and chemical properties. Adsorption studies on clays and soils. Effect of cyclic wetting and drying on swelling clays in laboratory and in nature (inundation and drought).

Genesis and transformation of clay minerals in soils, paleosols and loess. Crystal structure and chemistry of phyllosilicates during diagenesis, low grade metamorphosis, weathering and hydrothermal processes.

Clay minerals in radioactive waste disposal.