Adsorption Characteristics of Estrone to Aerobic Activated Sludge

Batch experiments were conducted to measure the sorption capacities of estrone (E1) to aerobic activated sludge. The effect of temperature on E1 sorption was investigated at the temperatures of 5-35oC. The results showed that E1 sorption equilibrium was reached at 15min. E1 sorption on the sludge fitted both Freundlich and linear sorption isotherm models. Distribution coefficients (Kd) of E1 to aerobic inactivated sludge was 546.5 L∙kg-1 at 25oC. The effect of temperature on sorption indicated that lower temperature benefited the sorption. The distribution coefficients (Kd) and sorption rate both decreased with the increased temperature. Kd of E1 to aerobic inactivated sludge was decreased by about 44%; the sorption rate was decreased by about 13% when temperature increased from 5 to 35oC. The specific sorption coefficient KOM or KOC was also used to describe the sorption capacity, which also decreased with increased temperature. Sorption thermodynamics indicated that the sorption process was exothermic and spontaneous.