[Adsorption characteristics of typical PPCPs onto river sediments and its influencing factors]

A batch equilibrium method was used to investigate the adsorption characteristics of ciprofloxacin (CIP), tetracycline (TC), sulfamethoxazole (SMX) and triclosan (TCS) onto Huangpu River sediments. Effects of adsorption time, initial concentration, solution pH and temperature on the adsorption process were studied. The results showed that the adsorption process of these PPCPs onto sediments was a two-step process: a rapid adsorption followed by a slow balance. The equilibrium time was about 4 h. The pH value had a significant effect on the adsorption of CIP, TC and TCS, whereas the effect on SMX adsorption was negligible. The kinetic results indicated that the adsorption processes followed the pseudo-second-order model, with adsorption rate in the range of 4.89 x 10(-3)-1.96 x 10(-2) kg x (min x mg)(-1). Adsorption isotherms were well described by the Freundlich and linear equations. As temperature increased, the amount of SMX and TC adsorbed increased, whereas CIP and TCS decreased. CIP, TC and TCS had a strong tendency to adsorb onto sediments, while the adsorption of SMX was unfavorable. When the initial concentration of PPCPs was 10 mg x L(-1), the equilibrium adsorption capacities of CIP, TC, SMX and TCS reached 702.8, 733.1, 54.7 and 695.0 mg x kg(-1), respectively.