Effect of Temperature on the Sorption of 17α-ethinylestradiol to Aerobic and Anaerobic Sludges

Abstract

Batch experiments were conducted to measure the sorption capacities of 17α-ethinylestradiol (EE2) to aerobic and anaerobic sludges. The effect of temperature on EE2 sorption was investigated at the temperatures of 10-30°C. The results showed that EE2 sorption equilibrium was reached at 30 min. EE2 sorption on the sludge fitted both Freundlich and linear sorption isotherm models. Distribution coefficients (Kd) of EE2 to aerobic and anaerobic inactivated sludges were 601.9 and 957.0 L/kg at 20°C separately. The effect of temperature on sorption indicated that Kd decreased with the increasing temperature. Kd of EE2 to aerobic and anaerobic inactivated sludges was both decreased by about 50% when temperature increased from 10 to 30°C. The specific sorption coefficient KOM or KOC was also used to describe the sorption capacity, which also decreased with increased temperature. Distribution coefficients (Kd) of EE2 to aerobic inactivated sludge were lower than those of anaerobic inactivated sludge. Sorption thermodynamics indicated that the sorption process was exothermic and spontaneous. Comparatively, sorption isotherms of the aerobic and anaerobic activated sludges were investigated at 20°C. EE2 sorption on activated sludge was also well correlated by both Freundlich and linear sorption isothermal model. Distribution coefficient (Kd) of EE2 to aerobic activated sludge was lower than that of anaerobic activated sludge.