ABSTRACT
The interactions between organic matter and clay minerals are among the most widespread reactions in nature. The adsorption of organic material by clay miner als has been widely investigated during the last decade and has been extensively reviewed (see, e.g., Weiss, 1969; Mortland, 1970; Theng, 1974, 1979; Yariv and Cross, 1979; Rausell-Colom and Serratosa, 1987; Lagaly, 1993). The interactions include cation exchange and adsorption of polar and nonpolar molecules. In these interactions, adsorption, in which physical or chemical bonds (long-or shortrange interactions, respectively) are formed between the mineral and the organic matter, is the primary process. In most adsorption reactions the clay minerals serve as the substrates and the organic entities are the adsorbed species. This is true for clay particles with sizes larger than those of the organic entities. However, in the case of huge polymers with very high molecular weights, such as cellulose, the clay particles may be located in the organic web (e.g., paper). In this case the polymer web should be considered as the substrate and the clay particle as the adsorbed material.
