Comparison of competitive and synergetic adsorption of three phenolic compounds on river sediment.

Knowledge of toxic chemical sorption by soil/sediment is critical for environmental risk assessment of toxic chemicals, especially for the multi-sorbate system in river ecosystem. Sorption characteristics of 2, 4-Dichlorophenol, 2, 4-Dinitrophenol and 2, 4-Dimethyphenol on sediment were investigated. Adsorption isotherms in single- and multi-sorbate systems fitted well the Freundlich model. The adsorption effects were different among three selected phenolic compounds in single- and multi-sorbate systems. The synergetic affect that 2, 4-Dinitrophenol and 2, 4-Dimethyphenol bring to 2, 4-Dichlorophenol can be explained by the compression of double electronic layer and the charge neutrality. Adsorption kinetic results showed that pseudo-second-order model can be used to describe the experimental data and the adsorption affinity of phenolic compounds influenced greatly by the adsorption velocity. The present study suggests that the fate and transport of emerging pollutants such as phenolic compounds could be affected in the presence of different hydrophobic pollutants in aquatic systems.