Sorption of Nonionic Organic Compounds to Inorganic Surfaces in Water

Empirically, we sometimes find that nonionic organic compound sorption on inorganic solids is best described with linear isotherms. Such is the case for observations of pyrene sorption on kaolinite suspensions (Fig. 11.6a Backhus, 1990). Generally, 

Partitioning of Apolar and Weakly Monopolar Compounds into the Region Near Mineral Surfaces 

Sorption III Sorption Processes Involving Inorganic Surfaces 

Two alternative explanations have been suggested which are both quite speculative. First, portions of mineral surfaces of intermediate polarity (e.g., siloxane regions, -Si-O-Si-) may permit some exchange of polar water and nonpolar organic sorbates (Hundal et al., 2001). Such surfaces occur in minerals like the faces of aluminosilicates. However, amorphous solids like silica (-Si-OH) and alumina (-A1-OH) have very hydrophilic exteriors when these inorganic materials are suspended in water. Yet these amorphous materials still clearly show sorption of apolar substances (e.g., Mills and Biggar, 1969a Schwarzenbach and Westall, 1981 Estes et al., 1988 Szecsody and Bales, 1989 Farrell et al., 1999). 

0 )bulk water a( H20)vjcjn t] ( i )vicinal water + (H20)bulk (11-14) 

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S Sorption of Nonionic Organic Compounds to Inorganic Surfaces in Water... 

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