Adsorption of phenol and chlorophenols on Ca-montmorillonite in aqueous solutions
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Adsorption of phenol, 2-chlorophenol, and 2,4-dichlorophenol on Ca-montmorillonite was studied with batch experiments at 25°C. The results from the experiments show that the amount of the adsorption of the phenolic compounds increases with chlorination, i.e., phenol <2-chlorophenol <2,4-dichlorophenol. This adsorption trend is due to the differences in the affinity of the phenolic compounds between the adsorbent and water, that is more affinity to water leads to less adsorption. The adsorption of phenol is unrecognizable, while 2,4-dichlorophenol is showing the highest adsorption density despite the repulsion between dissociated dichlorophenol anions and montmorillonite surface. Freundlich model fits moderately well to the adsorption isotherm of 2-chlorophenol and 2,4-dichlorophenol. The calculated model parameters aren=1.50, 0.49 and logk F =0.51, 1.09 for 2-chlorophenol and 2,4-dichlorophenol, respectively.
Key wordsadsorption Ca-montmorillonite chlorophenol phenol
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