【作者】 李红霞；

【导师】 赵新华；

【作者基本信息】 天津大学 ， 环境工程， 2008， 博士

【摘要】 随着冶金、化工、电镀和印染工业的蓬勃发展,重金属及其化合物被广泛使用,致使富含重金属的废弃物日益增多,重金属污染的加重导致进入城市排污河道沉积物中的重金属数量不断增加。由于环境中的重金属对人类具有潜在危害性,故对河道沉积物的修复和治理已成为当今世界各国普遍面临的环境问题。对城市排污河道沉积物的修复采用植物修复的方法,本文主要选用黑麦草和玉米两种植物对富含铅、镉、铜、锌、锰和镍等重金属的河道沉积物进行了温室栽种修复试验,并通过投加双氧水对植物修复的效果进行了对比研究。从植物种植前后和投加双氧水前后沉积物中重金属总量和存在形态的种类和数量的变化、根际环境对植物吸收和累积重金属的影响、根际微生物种群的变化、植物以及植物根际与非根际重金属累积重金属的情况对比、酶活性的变化等几个方面对植物修复的效果进行了分析,首次表明双氧水可以促进植物对沉积物中铅、镉、铜、锌、锰和镍等重金属总量和各种形态重金属数量的吸收累积,还可以改变不同形态重金属的种类,根际环境和微生物以及酶活性的变化表明沉积物中的重金属被有效活化,植物吸收、运移重金属的能力明显增强。通过对植物的根、茎和叶等各个部位吸收和累积重金属的情况看出,植物各个部位对重金属的吸收和累积机制各不相同,种植时间的延长可以使植物中累积的重金属数量增加,而修复效率下降。种植时间较长时植物中累积重金属的数量不同,沉积物中的有机物种类在植物种植前后有较大变化。根际分泌物的增多、沉积物中微生物种群的变化以及酶活性的变化均说明植物可有效修复沉积物中的重金属,特别是针对多酚氧化酶活性恢复较快这一点,本文首次提出将沉积物中多酚氧化酶活性的恢复作为判断植物修复沉积物效果的一个重要指标,从而为植物修复沉积物的研究工作提供新的参考。在分析植物吸收和累积沉积物中重金属机理的基础上,以植物吸收累积重金属的四个过程为模型依据,将植物吸收重金属的动态过程的数学模型表述成非线性动态系统的形式,并首次结合Lyapunov稳定性理论对植物吸收和累积重金属的非线性动态过程进行了严格的稳定性分析。稳定性结论可表达成线性矩阵不等式(Linear matrix inequality, LMI)的形式,求解方便。数值仿真和试验验证表明了所选模型的合理性及理论分析方法的有效性,该理论分析方法将为受重金属污染的河道沉积物的植物修复技术提供重要的参考作用。更多还原

【Abstract】 With the widely use of heavy metal and its compounds in flourishing development of industries of metallurgy, chemical engineering, electroplating and printing and dyeing, the remediation and treatment to heavy metal contamination has become a world-wide environmental problem because of the ever increasing heavy metal contaminants into urban river and even its potential danger to human beings. In order to remediate heavy metal in urban sewage river sediment, planting experiment and adding hydrogen peroxide treating research were conducted to study phytoremediation of lead, cadmium, copper, zinc, manganese and nickel in sediment by Lolium multiflorum and maize.Results showed after planting Lolium multiflorum the total concentration of heavy metal and different forms of heavy metal could be changed. In addition, the effect of rhizosphere, microorganism and urease activity in sediment could also help to uptake and translocation to heavy metal from sediment to plants. More important was the amounts and kinds of heavy metal or different forms heavy metal after adding hydrogen peroxide treating were largely changed. Heavy metals in sediment were activated efficiently and the ability of accumulation and translocation to heavy metals increased from sediment to plants.Through the research of uptake and accumulation of heavy metal in different parts of plant, results showed the root, stem and leaf had different phytoremediation mechanism to heavy metal. Even though extending planting time could make the amount of heavy metal in plant increased, efficiency of remediation decreased dramatically. The kinds and amounts of organics in sediment changed greatly. More rhizosphere exudates and microorganisms also helped to increase accumulation of heavy metal in plants. The activity of polyphenol oxidize had been increased after planting and adding hydrogen peroxide treating. The research firstly advised the activity of polyphenol oxidize could be considered as an important proof to judge the phytoremediation effect in sewage river sediment.Based on the mechanics of phytoremediation on heavy metal contaminants in sewage river sediment, the four dynamical processes of accumulation were described as a class of nonlinear dynamical systems. Then, the stability analysis of the nonlinear dynamical process of uptake and accumulation was achieved based on Lyapunov stability theory, and the result was formulated as the feasibility of linear matrix inequality (LMI) which could be solved numerically with available software. Numerical simulation and experimental data show the reasonableness of the dynamical model and the effectiveness of the proposed methods which will provide technical support for phytoremediation on heavy metal contaminants in sewage river sediment.更多还原