【作者】 景建宁；

【导师】 曹晓燕；

【作者基本信息】 中国海洋大学 ， 分析化学， 2011， 硕士

【摘要】 有机氯农药是公认的环境优先控制污染物,也是典型的持久性污染物（POPs）,具有难以降解性、半挥发性、生物蓄积性和高毒性,在自然界中可长期存在,并通过食物链富集,对人类健康和环境的危害极大。虽然我国已于1983年禁此了它的生产与使用,但由于其使用量大,在环境中降解缓慢、滞留时间长,使得有机氯农药仍然是在环境中检出率最高的一类POPs。这些有机氯农药可以通过大气输送、河流搬运及雨水冲洗等方式进入水体并汇于海洋。因为它们具有疏水性强、脂溶性高的特性,很容易被水体中的悬浮颗粒物质所吸附,并最终通过重力沉降等物理化学作用进入水体沉积物中;而沉积物中的有机氯农药也可通过再悬浮和解吸等作用重新进入水体造成二次污染,因此研究有机氯农药在水体和沉积物中迁移转化规律具有重要的意义,也是国内外关注的热点之一。本论文以有机氯农药DDT为研究对象,通过实验室模拟,采用湿筛法处理的胶州湾沉积物为吸附剂,以人工海水溶液为介质,研究了阴离子表面活性剂十二烷基苯磺酸钠（SDBS）存在下DDT在胶州湾沉积物上的吸附行为和吸附机理,并考察了影响因素对该吸附过程的影响,另外本研究还选取CTAB作为阳离子表面活性剂的代表,重点探讨表面活性剂类型对该吸附过程的影响及相关机理。论文得到如下主要结论:1)动力学研究表明,沉积物对DDT的吸附动力学曲线符合伪二级动力学吸附速率方程,SDBS和CTAB的加入均能促进DDT在沉积物上的吸附,且CTAB影响下更为显著。2)热力学研究表明,沉积物对DDT的吸附等温线较好的符合Freundlich等温式;在SDBS、CTAB和DDT共存的复合体系中,SDBS(C₀:5,10,15,30 mg·L^-1)和CTAB(C₀:15,30,50 mg·L^-1)的存在显著能提高沉积物对DDT的平衡吸附量,并使吸附等温线趋于线性。其中CTAB的影响更为显著;当SDBS的初始浓度为60 mg·L^-1时,SDBS的存在对吸附起抑制作用。3) p,p`-DDT和o,p`-DDT在三种处理方式的胶州湾沉积物上的吸附能力顺序为:HCl处理样﹥H₂O处理样﹥H₂O₂处理样。吸附主要与沉积物中的有机质含量有关。SDBS的存在促进DDT在H₂O₂处理沉积物上的吸附,抑制其在HCl处理沉积物上的吸附。4)环境因素研究表明,无论是单一体系还是复合体系,沉积物对DDT的吸附量随着盐度的增加而增加、温度的升高而降低。此外沉积物粒径的减小增加了两体系中沉积物对DDT的吸附量。5)热力学研究表明沉积物对DDT的吸附热力学函数均为ΔH^θ<0,ΔG^θ<0,ΔS^θ>0,即该吸附过程是一个放热、熵增的自发反应。加入15mg·L^-1SDBS、15mg·L^-1CTAB后,p,p`-DDT和o,p`-DDT在沉积物上的吸附有较大的标准吸附自由能变（|ΔG^θ|）和标准吸附焓变（|ΔH^θ|）,更小的标准吸附熵变（ΔS^θ）。更多还原

【Abstract】 Organochloyine pesticides （OCPs） are priority pollutants and typical persistent organic pollutants （POPs）. Because of their persistence, half-volatility and high toxicity in the environment, OCPs are great harmful to the environment and human health. Although their use has been restricted in our country since 1983, OCPs are still the most widespread POPs in the environment due to the persistence. These OCPs are transported in to marine environment through different ways, such as atmospheric transport and river transportion. Because OCPs have a strong affinity for suspended particles, they tend to subsequently settle down with sediments to the bottom of the ocean. Meanwhile, OCPs in sediments can also release into water by resuspension and lead to recontamination of water. Therefore the study on migration and transformation of OCPs in water and sediments is very important.In this thesis,the sorption behaviors of DDT on Jiaozhou Bay sediments were studied in the presence of an anionic surfactant dodecylbenzenesulfonic acid sodium（sodium dodecylbenzene sulfonate, SDBS） by laboratory experimently. In addition, the effect of CTAB （cetyltrimethylammonium bromide, a cationic surfactant） was also investigated. Major results and conclusions are shown as follows:1) The sorption kinetic process of DDT on the sediments followed the pesudo-second-order kinetic rate equation. The sorption of DDT was accelerated remarkably by the addition of SDBS and CTAB, and CTAB showed a more remarkable impact.2) The sorption isotherms of DDT on sediment could be described by the Freundlich isotherm. The results showed that SDBS with the initial concentrations of 5, 10, 15, 30 mg·L^-1 and CTAB with the initial concentrations15, 30, 50 mg·L^-1 could remarkably enhance the sorption of DDT and linearized the isotherms of DDT. CTAB played a more important role. SDBS had a negative effect on the sorption when the initial concentration was 60 mg·L^-1. 3) The sorption capability of DDT on the sediment with different treatment procedures was in such a sequence as: HCl treated﹥H₂O-treated﹥H₂O₂ treated. The sorption capability correlated with the contents of the organic matter in the sediments. The presence of SDBS could accelerate the sorption of DDT on H₂O₂ treated sediment while reduced the sorption of DDT on HCl treated sediment.4) The effects of environmental factors, such as temperature, salinity, on the sorption of DDT were obvious. The sorption amount of DDT on sediments increased with increasing salinity, but decreased with increasing of temperature in both single and combined systems.The sorption capacity was also increased with the decrease of sediment particle size.5) Estimation of thermodynamic parameters indicated that the sorption of SDBS and DDT was spontaneous （ΔG^θ<0） and exothermic （ΔH^θ<0） with an increase in the degree of freedom （ΔS^θ>0）. In the presence of 15 mg·L^-1SDBS and CTAB caused |ΔG^θ| and|ΔH^θ|values higher andΔS^θvalue smaller during the DDT sorption process.更多还原