摘要
采用批量定时取样法和批量平衡法,研究了低浓度阴离子表面活性剂十二烷基苯磺酸钠(SDBS)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)存在下胶州湾沉积物对DDT的吸附特性及机制.结果表明,吸附过程符合伪二级动力学方程,吸附等温线可用Freundlich等温式较好地描述.在实验浓度范围内,SDBS和CTAB均利于DDT在沉积物上的吸附,且吸附速率和吸附能力均随SDBS和CTAB初始浓度的增加而增大,其中CTAB的影响更为显著.以p,p'-DDT为例,当SDBS的浓度为10mg.L-1时,吸附速率常数k2由1.232×10-2 g.(μg.min)-1提高到4.193×10-2 g.(μg.min)-1,KF由2.866(μg.g-1)(L.μg-1)1/n增加到7.932(μg.g-1)(L.μg-1)1/n.另外本研究还分析了SDBS存在下温度对吸附过程的影响,结果表明,在283～308 K范围内,较低的温度有利于DDT的吸附,该吸附是一个自发的、放热的、熵增加的物理吸附过程,SDBS的存在使DDT在吸附过程中的ΔG0、ΔH0值更负,ΔS0值更小.该研究可为DDT在胶州湾中的迁移转化及其归宿提供一定的理论基础.
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.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第11期3327-3334,共8页
Environmental Science
基金
国家自然科学基金项目(40876037
40525017)
教育部"长江学者"奖励计划项目
山东省"泰山学者"建设工程专项
山东省科技攻关项目(2006GG2205024)
