河流沉积物对典型PPCPs的吸附特性及其影响因素

采用批平衡实验方法,研究了黄浦江沉积物对环丙沙星(CIP)、四环素(TC)、磺胺甲唑(SMX)和三氯生(TCS)的吸附特性,探讨了吸附时间、初始浓度、溶液p H值和温度等因素对吸附过程的影响.结果表明,CIP、TC、SMX和TCS在沉积物中的吸附过程均呈现先快速后缓慢的变化趋势,等温吸附平衡时间约为4 h.溶液p H值对CIP、TC和TCS的吸附过程具有显著影响,但对SMX的吸附影响较小.目标PPCPs吸附过程符合准二级反应动力学方程,吸附常数为4.89×10-3~1.96×10-2kg·(min·mg)-1.吸附等温线能较好地符合Freundlich方程和线性方程,高温不利于CIP和TCS吸附,而利于TC和SMX吸附.沉积物对CIP、TC和TCS的吸附能力较强,但对SMX吸附效果较差,当初始浓度为10 mg·L-1时,沉积物对CIP、TC、SMX和TCS的平衡吸附量分别可达702.8、733.1、54.7和695.0 mg·kg-1.

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 4.89×10^-3-1.96×10^-2 kg·(min·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·L^-1, the equilibrium adsorption capacities of CIP, TC, SMX and TCS reached 702.8, 733.1, 54.7 and 695.0 mg·kg^-1, respectively.