| A batch sorption study was carried out to investigate the sorption behaviors of DDT onto JiaoZhou Bay sediment in the presence of an anionic surfactant sodium dodecylbenzene sulfonate(SDBS), and a cationic surfactant, cetyltrimethylammonium bromide(CTAB) with low concentrations. The results indicated that the sorption process followed the pseudo-second-order model and the sorption systems could be well described by the Freundlich type. Within the investigated concentrations of CTAB and SDBS，both SDBS and CTAB increased the sorption of DDT to sediment. The sorption rate and capacity increased with increasing SDBS and CTAB concentrations, and CTAB showed a significant impact. Take p,p′-DDT as an example, the sorption rate constant increased from 1.232×10-2 g·(μg·min)-1 to 4.193×10-2 g·(μg·min)-1 and the Freundlich coefficient increased from 2.866(μg·g-1)(L·μg-1)1/n to 7.932(μg·g-1)(L·μg-1)1/n when the SDBS concentration was 10 mg·L-1. The influence of temperature on sorption of DDT in the presence of SDBS was also studied. Within the temperature range of 283-308 K, lower temperature had a positive effect on the sorption. The thermodynamic parameters showed that the sorption was spontaneous and exothermic, and the randomness was increased during the process. Furthermore, the presence of SDBS caused lower ΔG0 , ΔH0 and ΔS0 values. This study provided theoretical foundation for migration, transformation and fate of DDT in Jiaozhou Bay sediment. |
