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题名: PFOS的环境界面行为及迁移规律研究
作者: 游春
学位类别: 博士
答辩日期: 2010
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 潘纲
关键词: PFOS ; 吸附 ; 针铁矿 ; FT-IR ; 迁移
中文摘要:       PFOS作为一种新型持久性有机污染物,在全球范围内广泛分布。研究其在环境中的迁移转化规律,探讨PFOS在环境中的源与汇是目前研究的一个重要方向。本论文主要通过研究PFOS在各种吸附剂上的吸附解吸行为,总结PFOS的吸附规律,并进一步通过FT-IR和XANES等光谱手段探索其微观吸附机理。另一方面,对PFOS在河口区的分布进行调查,并结合实验室实验,考查影响PFOS分布的环境因素,解释其在水环境中的迁移规律。 PFOS在土壤上的吸附等温线呈非线性,符合Langmuir吸附模型,六种土壤样品的模拟最大吸附量Cmax在6.80~30.04 mg/Kg之间。吸附等温线与沉积物理化性质无显著相关性,土壤有机质性质和土壤无机成份等因素综合对PFOS在土壤上的吸附造成影响。碱提土壤余土与原土壤相比对PFOS的吸附能力增强,吸附等温线线性增大。解吸实验显示PFOS在四种土壤余土上的吸附均为不可逆吸附。结合粘土矿物-腐殖酸二重模型物及其单体吸附实验可知,土壤去除富里酸和胡敏酸后,结构发生变化,土壤余土中孔隙增大,土壤无机质比表面增大,导致土壤余土与PFOS的吸附能力增强。 PFOS在针铁矿上的吸附受pH、离子强度和离子强度剂种类影响。针铁矿的吸附能力随pH的增加而降低;随吸附体系中离子强度的增加而增加;在含有二价阳离子的吸附体系中,PFOS更易吸附在针铁矿表面。PFOS在针铁矿上的吸附方式包括静电引力和内层吸附。内层吸附包括形成二重络合物和通过二价阳离子形成的三重络合物。内层吸附导致吸附不可逆,并且由于吸附体系中二价阳离子的存在,增加了吸附的不可逆性。针铁矿吸附样品的FT-IR实验检测到Fe-O-S特征吸收峰的存在,从微观结构上证明了PFOS通过形成化学键吸附到了针铁矿上。针铁矿吸附样品的XANES谱图经过分峰和一阶导数分析可观察到S元素主吸收峰较为明显的位移,说明吸附反应后针铁矿中O原子的吸引使S元素的K边吸收的主吸收峰向低能量移动。PFOS表现出极性污染物的吸附特性。 对PFOS在长江口地区水体和底泥中的浓度状况进行了调查。分析显示,PFOS在水体中的浓度为703.0~36.3 ng/L,近岸地区由于人类活动造成的生活污水及污水处理厂排水可造成水体中的高PFOS浓度。底泥中PFOS浓度为38.4~536.7 ng/g,底泥柱状样品的PFOS含量随采样深度的增加而降低,从一定程度上反映出近年来水体中PFOS加重的环境状况。结合PFOS在沉积物上的吸附解吸特征和水土分配系数 (Kd) 与盐度的相关性分析,可以推断PFOS与底泥的亲和性在长江口盐潮入侵盐度增高时增高。河口区是PFOS在水体中迁移的一个重要的汇,研究者应对这一复杂区域对有机污染物归趋的影响给予更多的关注。
英文摘要:
      PFOS is a new persistent organic pollution, which distributed worldwide. Study the transport rules of PFOS, and reveal the sink of PFOS in environment is an important study direction at present. The thesis indented to study the behavior of PFOS on the environmental interface through its sorption and desorption on kinds of sorbents, and summarize the sorption rule of PFOS. Furthermore, Fourier-infrared (FT-IR) spectra and X-ray near edge spectra (XANES) were used to study the microscopic structures of PFOS. The distribution of PFOS in estuary was investigated to find the most important affecting environmental factors and reveal the transport rule of PFOS in aquatic environment. The sorption isotherms of PFOS on soil were nonlinear, fitting for the Langmuir sorption model. The modeled maximum sorption amount of the six soil were in the range of 6.80~30.04 mg/Kg. There was no significant relationship between the sorption and the physicochemical characteristics of soil, the component of organic and inorganic matter of soil affected the sorption of PFOS on soil jointly. The sorption ability of soil after humic acid extraction was greater than the soil without treatment, and the linearity also increased. The desorption experiment suggested that the sorption of PFOS on treated soil were all irreversible. Analyzed with the sorption experiment of PFOS with clay, humic acid and model sorbent, we found that the combination of clay and humic acid would change the structure of clay, and decrease the sorption of PFOS on clay. The sorption of PFOS on goethite was affected by pH, ionic strength and the ionic solution itself. The sorption amount of PFOS on goethite decreased when the pH value increased, and increased with the increasing of ionic strength. In the sorption system had divalent cation, more PFOS could sorb onto goethite. PFOS sorbed onto goethite through static attraction and subsurface adsorption such as duplex complexes and triple complexes. Subsurface adsorption caused the sorption irreversibility of PFOS, and the sorption irreversibility increased for the appearance of divalent cation. There was characteristic absorption peak of Fe-O-S in the FT-IR spectra of sorption samples, which proved that PFOS sorbed on goethite through chemical bond. There was significant displacement of the main absorption peaks in XANES, which suggested the electron environment of S in PFOS changed after the sorption. S in PFOS was attracted by O atom in goethite, and its main absorption peak moved to lower energy. PFOS acted as a polar organic pollutant. We investigated the distribution of PFOS in the water and sediment from Yangtze River Estuary. The concentration of PFOS in water samples ranged from 703.0 to 36.3 ng/L. Human activities contributed a lot to this pollution. The concentration of PFOS in sediment samples ranged from 38.4 to 536.7 ng/g, and decreased as the sampling depth increased. The result reflected the pollution of PFOS in this area became more serious in recent years. Analyzed with the results of sorption experiment and the correlation between Kd and salinity, it was clear that the affinity of PFOS onto sediment increased with salinity. Estuary is one of the important sink for PFOS, we should pay more attention to this area.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35017
Appears in Collections:环境纳米技术与健康效应重点实验室_学位论文

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Recommended Citation:
游春. PFOS的环境界面行为及迁移规律研究[D]. 北京. 中国科学院研究生院. 2010.
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