【作者】 韩化雨；

【导师】 曹晓燕；

【作者基本信息】 中国海洋大学 ， 分析化学， 2010， 硕士

【摘要】 虽然单个污染物质构成的环境污染时有发生,但工农业生产的高速发展导致越来越多人工合成的有机污染物进入河流和海洋,事实上绝对意义上的单一污染已经不再存在,污染多具伴生性和综合性,即多重污染物质形成复合污染。由于共存污染物之间存在着复杂的交互作用,使得它们在海洋环境中往往有着和其单独存在时不同的迁移转化行为,这一点开始引起化学家和环境学家的广泛重视。DDT是一种持久性有机氯农药,曾在六十到八十年代大量使用,虽然目前已经被禁用或限用，但其高残留、生物蓄积和生物放大特性使其依然广泛存在于海洋环境中。阳离子表面活性剂是生活和生产中大量使用的一类表面活性剂,含有此类物质的废水排入海洋使得这类表面活性剂对海洋环境带来毒害的同时还显著影响着共存污染物的迁移转化行为。因此，研究阳离子表面活性剂和DDT复合污染体系的吸附作用,有利于了解其在环境中的迁移转化和生物生态效应,可为控制污染提供依据。本论文研究了沉积物的表面电荷性质,并以人工海水溶液为介质,以十六烷基三甲基溴化铵(CTAB)和DDT为研究对象,探讨了两种有机污染物共存时在沉积物上的吸附动力学和热力学行为,并就环境因素包括温度,pH和介质盐度对吸附的影响进行了研究。结论如下：1)本文所使用的胶州湾沉积物带有一定量的永久负电荷,三种离子强度下(0.001,0.01,0.1mol/L NaNO3)沉积物表面位密度密度(Ds)在4.58～5.15 sites·nm-2之间。2)动力学研究表明,沉积物对CTAB的吸附动力学曲线符合伪二级吸附速率方程,吸附速率常数随温度的升高而增大,随初始浓度的增加先增大后减小；沉积物对DDT的吸附动力学曲线符合伪二级吸附速率方程,CTAB的加入能够显著加快DDT在沉积物上的吸附。3)热力学研究表明,沉积物对CTAB或DDT的吸附等温线较好地符合Freundlich等温式；在CTAB和DDT共存的复合体系中,CTAB(C0:5,20,50mg·L-1)的存在能够显著提高沉积物对DDT(C0:0.057～0.915 mg·L-1)的平衡吸附量,并使吸附等温线趋于线性；而DDT(C0:0.457,0.915 mg·L-1)的存在并没有对CTAB(C0:10～160 mg·L-1)在沉积物上的吸附产生显著影响。4)环境因素研究表明,无论是单一体系还是复合体系,随着介质离子强度的增加和温度的降低,沉积物对CTAB和DDT的吸附量均显著增加。此外pH的增大还增加了单一体系中沉积物对CTAB的吸附量。5)热力学研究表明沉积物对CTAB和DDT的吸附热力学函数均为△Hθ<0,ΔGθ<0,△Sθ>0,即该吸附过程是一个放热、熵增的自发反应。加入20 mg·L-1 CTAB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(|△Gθ|)和标准吸附焓变(|△Hθ|),更小的标准吸附熵变(△Sθ)更多还原

【Abstract】 Although environmental pollution caused by single contaminate happened frequently, with the rapid developments of agriculture and industry, a great variety of anthropogenic organic pollutants enter marine environment and constitute combined pollution systems.In these combined systems,there are mutual interactions among each of these pollutants, which may make the behavior of each pollutant different from that of the one existing singly.This combined effect between various pollutants has attracted much attention of environmentalists.Dichloro diphenyl trichloroethane (DDT) is a persistent organochlorine pesticide, which has been extensively used between 1960s and 1980s.Although their usage has been banned or severely restricted for the past decades,DDT and its metabolites can be still detected in water, sediment and animals due to their persistence, bioaccumulation and biomagnifications.Quaternary ammonium compounds (QACs) have a wide range of commercial and consumer uses.Wastewater containing QACs has been finally discharged to coastal waters, besides a great harmness to the ecosystem, these surfactants simultaneously affect the fates of coexist contaminants.Therefore,investigation on the combined sorption behaviors of pollutants on sediments is realistically significant to study their transference deeply.In this thesis, the surface charge properties of sediment, the sorption kinetics and thermodynamics of cetyltrimethylammonium bromide (CTAB)and/or DDT are comprehensively studied in the system of sediment-artificial seawater. Furthermore,the effects of environmental factors such as temperature, salinity and pH are also investigated. The main results are as follows:1)The sediment has a quality of negative permanent charge and their specific surface sites (Ds) in three ionic strengthens(0.001,0.01,0.1 mol·L-1 NaNO3) are between 4.58-5.15 sites·nm-2. 2)The sorption kinetic process of CTAB and/or DDT on the sediments has been proven to follow the pesudo-second-order kinetic rate equation.The sorption rate of CTAB increased with increasing temperature, while first increased and then decreased with increasing initial concentration.The sorption of DDT was accelerated remarkably with the addition of CTAB.3)The sorption isotherms of CTAB or DDT on sediment can be described by the Freundlich isotherm. The results showed that CTAB with the initial concentrations of 5, 20,50 mg·L-1 could remarkably enhance the sorption of DDT (C0:0.057～0.915 mg·L-1) and linearized the isotherms of DDT. However. DDT with the initial concentrations of 0.457 and 0.915 mg·L-1 did not affect the sorption extent of CTAB (C0:10～160 mg·L-1) in the experiment.4)The effects of environmental factors,such as temperature, salinity and pH,on the sorption of CTAB and/or DDT were obvious.The sorption capability was increased under higher salinity and decreased temperature for the sorption of CTAB and/or DDT in both single and combined systems.As for CTAB in the single systems,the sorption capability also increased with increasing pH.5)Estimation of thermodynamic parameters indicated that the sorption behavior of CTAB and DDT was spontaneous (ΔGθ<0) and exothermic (ΔHθ<0) with an increase in the degree of freedom (ΔSθ>0).In the presence of 20 mg·L-1 CTAB,sorption of p,p’-DDT and o,p’-DDT have relatively more negativeΔGθ,ΔHθand less positiveΔSθ.更多还原