【作者】 郑蕾；

【导师】 孙德智； 田禹；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2006， 博士

【摘要】 胞外聚合物（extracelluar polymeric substances, EPS）是活性污泥的第三大组份,对重金属有良好的富集作用,由于其重要特性和位置而成为研究热点。目前关于EPS的组成、性质、提取方法、对多种重金属的富集作用等方面研究均取得了一定进展,但关于其吸附重金属的效能和机制研究较少,针对重金属污染严重的现状和现存技术成本高等局限性,本文考察了剩余污泥胞外聚合物对水中和土壤中典型污染重金属(Cd²⁺、Zn²⁺、Pb²⁺)的吸附效能,并对其机制作了研究,最终在剩余污泥减容减量的同时用于重金属污染的控制,达到以废治污的目的。本文首先以三种广泛存在的活性污泥（市政污水污泥、饮料废水好氧污泥、饮料废水厌氧污泥）为研究对象,考察了提取方法对污泥胞外聚合物组分性质的影响规律,并分析了EPS对活性污泥脱水性能影响和影响机制,确定以蒸汽提取法为最佳提取方法,-20℃为EPS最佳储存温度, EPS的提取有助于污泥的减容减量。根据以上研究,模拟市政污水和饮料废水培养污水污泥提取EPS,以其为吸附剂考察pH值、EPS投加量、吸附时间对水中Cd²⁺、Zn²⁺吸附效能的影响规律、热力学吸附特征及共存离子对胞外聚合物吸附Cd²⁺、Zn²⁺的影响,结果表明,胞外聚合物对Cd²⁺和Zn²⁺吸附较好,在初始投加浓度为20mg/L条件下,最佳pH值均为6,EPS最佳投加量分别为375mg/L和250mg/L,此时,EPSⅠ吸附率约为27mg/g和47.5mg/g,EPSⅡ对Cd²⁺和Zn²⁺吸附率分别约为19.5mg/g和40.5mg/g,EPSⅢ吸附率约为17mg/g和37mg/g。三种EPS对Cd²⁺和Zn²⁺的吸附过程均可分为快速吸附～慢速吸附～吸附平衡三个阶段, Langmuir方程可描述三种EPS在常温下对Zn²⁺和Cd²⁺的热力学过程,EPS对Zn²⁺的吸附能力大于Cd²⁺。本文考察了EPS对两种不同性质土壤中Cd²⁺、Zn²⁺、Pb²⁺的吸附效能,分析了pH值、EPS浓度、吸附时间对吸附效能的影响规律,并考察了EPS处理前后土壤性质的变化,和EPS从土壤中提取重金属的动力学,最后通过分析土壤中金属形态解释了EPS去除土壤中重金属的机制。结果表明,EPS浓度、pH、吸附时间均对EPS去除土壤中Pb²⁺,Cd²⁺和Zn²⁺影响较大,EPSⅠ效果最好,土壤A ,Pb,Cd和Zn分别在pH3⁶.5,4.5⁶.0和3.0时取得最大去除率,分别约为50%、60%和70%;土壤B,Pb、Cd和更多还原

【Abstract】 Extracelluar polymeric substances（EPS） is the third largest components of activated sludge characterized by efficient heavy metal enriching ability and has caused extensively attention for its special identity and important position. Today, achievements have obtained from the research on the components, characteristics, extraction methods and metal-enrich-ability of EPS. However, few researches have been conducted on the efficiency and mechanisms of EPS adsorbing heavy metals. Considering the serious heavy metal contamination of water and soil and the limits of exist treatment technology, efficiency and mechanisms of EPS adsorbing the classic heavy metal, Pb²⁺, Cd²⁺, Zn²⁺, both from contaminated water and soil were studied. Reduction in volume and mass of waste activated sludge by extraction of EPS enlightens the meaning of using EPS in heavy metal contamination control.In this paper, extraction methods were compared and effects of temperature on the composition of EPS from 3 extensively exist activated sludge （from treatment of municipal wastewater and anaerobic, aerobic treatment of Cola wastewater） were investigated. The influences of EPS on dewaterbility of sludge were also studied. It was believed that to this research, steaming is the best extraction method to obtain EPS from sludge; -20℃is the proper temperature for EPS storing; Extraction of EPS benefits the reduction in volume and mass of sludge.Based on the above research, EPS from sludge cultivated by simulated municipal and Cola wastewaterwere were used as adsorbent for heavy metal removing. Effects of pH, EPS dosage and duration time on the removal efficiency of Cd²⁺, Zn²⁺ from water were investigated. The results showed: EPS was efficient in Cd²⁺, Zn²⁺ adsorption. The optimal pH value is 6.0. The optimal dosage of EPS is 375mg/L and 250mg/L. At optimal condition, the absorption efficiency reaches 27mg/g of Cd²⁺ and 47.5mg/g of Zn²⁺ by EPSⅠ, 19.5mg/g of Cd²⁺ and 40.5mg/g of Zn²⁺ by EPSⅡ, 17mg/g of Cd²⁺and 37mg/g of Zn²⁺ by EPSⅢ. The adsorption processes of Cd²⁺and Zn²⁺ with EPS both have two steps: fast adsorption and slow adsorption. Langmuir isotherm equations could describe更多还原