Adsorption of select phenol derivatives by dolomite

Abstract

Laboratory experiments were performed to investigate the behaviour of six phenols: 4-chloro-m-cresol, 2,4-dimethylphenol, 2,4-dinitrophenol, 4-nitrophenol, pentachlorophenol, and 2,4,6-trichlorophenol, in dolomite aquifers. The phenols are toxic, persistent in aquatic environments, and used widely in the chemical and manufacturing industry. Dolomite aquifers are common sources of water in many parts of the country.

The experimental results are that, with the exception of the chlorinated phenols, little, if any, of the phenols adsorb onto dolomite at temperatures of 5° and 22°C and at concentrations from 0·1 to 10 mg litre⁻¹. Pentachlorophenol adsorbs most strongly, with as much as 22% adsorbing from groundwater onto dolomite. No processes of phenol degradation were detected in the experiments, with some experiments lasting 21 days. Thus, phenols dispersed in an area where they can leach and contaminate dolomite groundwater aquifers would pose a threat to human health and the environment. In contrast to dolomite, chemical sorbents strongly adsorb the phenols and could be used for groundwater cleanup.