INFLUENCE OF CHLORINE ATOM NUMBER IN CHLOROPHENOL MOLECULES ON THEIR ADSORPTION ON ACTIVATED CARBON

摘要

Kinetics and equilibria of 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol adsorption from aqueous solutions onto powdered activated carbon was investigated. The experimental systems were analyzed in terms of C1 atom number in chlorophenol molecules. The kinetics was fitted with the pseudo-second-order model better than pseudo-first-order. The adsorption equilibria of all three adsorbates were described by Freundlich equation better (higher R~2 values) than by Langmuir equation. The Freundlich equation constant K_F was decreasing when C1 atom number in chlorophenol molecules increased. Comparison of our data with results of other papers is difficult because of different adsorbate concentration units (mg L~(-1) or mmol L~(-1)), or too low equilibrium concentrations (C_e) of adsorbates used. Therefore, for this purpose, we recommend using the relative concentration i.e. C_e/Cs (Cs -solubility).