Chapter 7.3 Clay Mineral Organic Interactions

Abstract

Publisher Summary This chapter reviews clay mineral–organic interactions. Clay minerals have been implicated in the abiotic origins of life on the Earth because of their ability to adsorb, protect, concentrate, and transform biomolecules. Clay minerals can react with different types of organic compounds in particular ways. Kaolin species (kaolinite, nacrite, and dickite) adsorb particular types of neutral organic compounds among the layers. The penetration of organic molecules into the interlayer space of clay minerals is called “intercalation.” Intercalated guest molecules can be displaced by other suitable molecules. A broader diversity of reactions characterizes the behavior of 2:1 clay minerals. Water molecules in the interlayer space of smectites and vermiculites may be displaced by many polar organic molecules. Neutral organic ligands can form complexes with the interlayer cations. The interlayer cations may be exchanged by various types of organic cations. Alkylammonium ions are widely used in modifying bentonites. The other important group of organic compounds is cationic dyes and cationic complexes. The interaction of clay minerals with different types of polymers including polypeptides and proteins was intensely studied many decades ago and recently seems to revive.