Sorption and transformation f phenols on clay surfaces: Effect of exchangeable cations

Cu-, AI-, and Fe(IIl)-montmorillonite from both vapour and aqueous phases were examined by IR spectroscopy. All the phenols were sorbed by the clays but were modified to different degrees depending on the exchangeable cations and on the amount and type of alkyl substitution fthe phenols. Sorption of 2,6-dimethylphenol fr m aqueous solution was irreversible, and the extent of sorption followed the order Fe-> A1-> Cu-> Ca-clay. Both transition and non-transition metal cations were effective in transforming the phenol sorbates and heating the clay/phenol complexes further enhanced transformation. The results are discussed in terms of the nature of the transformation products and the likely role of radical reactions intheir formation. The clay component of soils and sediments can play an important part in the fate of organic compounds which may enter the environment. Phenolic compounds constitute eleven of the one hundred and twenty-six chemicals which have been designated as priority pollutants by the US Environmental Protection Agency (Chapman et al., 1982). These phenols can enter the environment through disposal of industrial wastes, or by biological and chemical degradation of a number of aromatic ompounds, including some pesticides (Wood, 1982). Sorption is considered to be an important process in the transport of man