ADSORPTION OF PHENOLIC-COMPOUNDS ON FLY-ASH

Adsorption isotherms for adsorption of phenol, S-chlorophenol, and 2,4 -dichlorophenol from water onto fly ash were determined. These isother ms were modeled by the Freundlich isotherm. The fly ash adsorbed 67, 2 0, and 22 mg/g for phenol, chlorophenol, and 2,4-dichlorophenol, respe ctively, for the highest water phase concentrations used. The affinity of phenolic compounds for fly ash is above the expected amount corres ponding to a monolayer coverage considering that the surface area of f ly ash is only 1.87 m(2)/g. The isotherms for contaminants studied wer e unfavorable, indicating that adsorption becomes progressively easier as more solutes are taken up. Phenol displayed a much higher affinity for fly ash than 3-chlorophenol and 2,4-dichlorophenol.