[Adsorption characteristics of 17beta-estradiol to anaerobic and anoxic sludge]

Adsorption tests were performed to measure the adsorption capacity of anaerobic and anoxic inactivated sludge for 17beta-estradiol. The effects of pH and temperature were also investigated. The adsorption equilibrium was established in 30 min; no significant pH effect was observed in the pH range of 6-9 at 20 degrees C; when pH >9, the adsorptive capacities decreased with increasing pH value; the adsorptive capacities decreased with increasing temperature. The experimental data of equilibrium concentrations were well correlated by both Freundlich and linear adsorption isothermal models. Distribution coefficients (Kd) decreased with increasing temperature. The distribution coefficients (Kd) of anaerobic inactivated sludge were 629.2 (10 degrees C) > 534.9 (20 degrees C) > 405.6 (30 degrees C), and those of anoxic inactivated sludge were 601.2 (10 degrees C ) > 491.3 (20 degrees C) > 360.1 (30 degrees C). Comparatively, Freundlich parameters K(F), 1/n and Kd of the anaerobic and anoxic activated sludge were measured at 20 degrees C; Distribution coefficient of anoxic activated sludge was lower than that of anaerobic activated sludge. No significant differences were observed between activated and inactivated sludge. The adsorption abilities of anaerobic activated/inactivated sludge were greater than those of anoxic activated/inactivated sludge.