Sorption and transformation of phenols on clay surfaces: effect of exchangeable cations

Abstract

The sorption and transformation of phenol, 2-methylphenol, 3-methylphenol, 2,6-dimethylphenol, 3,5-dimethylphenol, and 2,4,6-trimethylphenol, by homoionic Na-, H-, Ca-, Cu-, Al-, and Fe(III)-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 of the phenols. Sorption of 2,6-dimethylphenol from aqueous solution was irreversible, and the extent of sorption followed the order Fe- > Al- > 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 in their formation.

Polymerization of 2,6-Dimethylphenol on Smectite Surfaces

“…The absorption bands in the 1670-1630-, 1570-1530-, and 1480-1450-cm -l regions, absent in the phenol spectra, indicate the presence of alteration products of the phenol. These absorption bands indicate that the transformation of the phenol varied with exchange cation following the order Fe > AI > Ca > Na, and may result from quinone-type transformation products (Isaacson and Sawhney, 1983).…”

“…Differential IR spectra of the thin films were recorded using a Perkin-Elmer 281 Infrared Spectrophotometer (Isaacson and Sawhney, 1983). Differential spectra record changes in the absorption peaks resulting from the treatment when the treated sample is balanced against the control sample in a dual-beam IR instrument.…”

“…Whereas di-, tri-, and tetracondensates of phenols were identified in the phenol system, no rational multiples of benzene were produced in the benzene system. Isaacson and Sawhney (1983) recently studied sorption of a number of phenols by a smectite with transition metal cations Cu > and Fe > and nontransition metal cations, Na +, Ca 2+, and AP + on the exchange sites. Infrared spectra of the clay-phenol complexes revealed that all of the clays transformed the sorbed phenols; however, the transformation of the phenols occurred to a much greater extent in clays with transition metal cations than in those with nontransition metal cations.…”

Chemical reactions of organic compounds on clay surfaces.

“…Dimers, trimers, and tetramers of the parent phenol, and the corresponding quinones were found by using HPLC and mass-spectrometry. This polymerization reaction of phenol and methylphenols was favored in the presence of air, but not for chlorophenols (52)(53)(54). The degree of polymerization and its amount was in the order of Fe-> Al-> Ca-> Na-clay.…”

Preparation and characterization of polyaniline-silica composite material

“…IGC has been applied successfully for the characterization of polymers (Donnet et al 1992;Osmont et al 1989), clay materials (Tiburcio et al 1991;Lara et al 1991), zeolites (Ligner et al 1989), carbon fibres (Chehimi et al 1997;Carrot et al 1984), graphite (Hradil et al 1984), glass (Roshchina et al 2001;Meyer, 1980) and various other organic and mineral fillers (Klahre et al 2004). It has also been demonstrated to be suitable for the characterization of microporous (Dorris et al 1980;Isaacson and Sawhney, 1983 , 1989), and lamellar materials (Susarla et al 1992).…”