全氟辛烷磺酸盐在天然水体沉积物中的吸附-解吸行为

通过平衡振荡试验,探讨了沉积物的理化性质(总有机碳含量、粒度、阳离子交换容量、比表面积)、离子强度和pH值对全氟辛烷磺酸盐(PFOS)吸附-解吸行为的影响.结果表明,在中性环境中PFOS在水和沉积物中有机质之间的分配作用是影响其吸附行为的重要机制,分配系数Kd与沉积物中总有机碳含量呈显著正相关(r=0.96,p＜0.01,n=15).随着离子强度的增加,盯OS在沉积物中的吸附量明显增大,解吸滞后现象更加明显.pH的影响在酸性和碱性条件下(pH 4～8.5)呈现出不同的特点,在酸性条件下随pH值增加,PFOS在沉积物中的吸附量减少;在pH接近中性时达到最小值;在碱性条件下随pH增加,吸附量增加.

Sorption and desorption behavior of perfluorooctane sulfonate on the natural sediments

In the present study, sorption and desorption behavior of PFOS in water-sediment system was studied, and the influence of physicochemical of sediments (total organic carbon, cation exchange capacity, particle size, and BET surface area), ion strength and pH values were evaluated. Results showed that partition between organic matter of sediments and water was the main factor controlling the PFOS sorption behavior at pH 7.0, and the partition coefficient K_s was positively correlated with total organic carbon of sediments(r=0.96,n=15,p<0.01). The sorption capacity of PFOS increase greatly with ion strength, and the desorption hysteresis also increased considerably. The sorption capacity of PFOS decreased with pH values from 4.0 to 7.0, while increased with pH values from 7.0 to 8.5.