Adsorption isotherms of 17 beta-estradiol on granular activated carbon (GAC)

The adsorption characteristics of three types of activated carbon for 17 be ta -estradiol were studied by long term experiments to assess the time whic h is necessary to reach equilibrium between the solid and the liquid phase. The adsorption kinetics were measured by liquid scintillation counting usi ng radio-labelled 17 beta -estradiol at various concentrations of 17 beta - estradiol in the ppt range. 17 beta -estradiol is quickly adsorbed and cond itions close to equilibrium were reached after 50-180 min. The equilibrium concentrations were calculated to be at 49-81% of the initial concentration in the concentration range between 1 and 100 ng/l, with 0.51 ng/l for a I ng/l and between 5.9 and 14.6 ng/l for 100 ng/l initial concentration. (C) 2001 Elsevier Science Ltd. All rights reserved.