树脂改性纳米铁修复铅污染地下水的研究

发布时间：2017-12-31 19:01

本文关键词：树脂改性纳米铁修复铅污染地下水的研究　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：地下水是水资源的重要组成部分，是解决我国工业、农业、生活用水的重要资源。近几十年，经济粗放式发展使得对自然资源开发利用强度日渐增大，地表水污染严重，地下水环境也遭受不同程度的污染。重金属是地下水中一种重要的污染物。重金属高稳定、难以降解的特性使得地下水重金属污染具有危害不可预测的特点。铅作为典型的重金属污染物，是著名的“五毒”之一，具有致畸、致癌、致突变的“三致”特性，随着铅污染事件增多，铅污染地下水修复势在必行。零价铁简单易得、反应性强，可与多种污染物发生反应，零价铁处理环境污染物成为近年来十分活跃的研究领域。纳米级零价铁粒径小、比表面积大、表面能大，在保持零价铁化学性的基础上具有更高的反应活性、强还原性及吸附性，但是纳米铁易团聚、稳定性差，抗氧化性差的特点使其在应用中受到局限，因此纳米铁的改性成为了必然。本研究讨论树脂改性纳米铁应用于铅污染地下水修复的可行性，并且在静态批实验的基础上，构建有机玻璃柱反应装置，研究动态条件下的修复效果，研究成果如下：（1）对实验所用树脂纳米铁进行SEM和XRD表征，确定其形态、主要成分及稳定性，结果表明粒子粒径约为50-200nm，整体呈絮状排列，主要成分为Fe(0)，具有很强的空气稳定性及抗氧化性，在空气中，暴露条件下可稳定存放60天以上；（2）研究树脂纳米铁对铅污染地下水的修复效果，确定反应基本条件，探究反应动力学及反应机理。结果表明，树脂纳米铁对铅污染物的去除符合准一级动力学方程，其机理为混凝吸附和表面还原共同作用。树脂纳米铁对铅的去除率受多种因素影响，随树脂纳米铁投加量增大、初始污染物浓度减小铅的去除率增加；水体中的DO作为电子受体可以与Fe(0)发生反应，与Pb2+竞争电子，因此地下水无氧环境有利于反应的进行；初始pH不同，处理效果略有不同，pH过大或过小均不利于反应进行，本实验中最适pH为4；（3）研究常见地下水离子Cl-、SO42-、HCO3-、Ca2+、Mg2+对树脂纳米铁修复铅污染地下水的影响。地下水离子成分存在时，树脂纳米铁对铅污染物的处理仍符合准一级动力学方程，但是，速率常数大小与离子种类和浓度均有关系；SO42-和Cl-可以破坏纳米铁表面钝化层或形成绿锈，促进铅的去除；HCO3-存在时与Pb2+生成PbCO3沉淀，反应初期就使污染物浓度大量减少，而且HCO3-的pH缓冲性也促进了反应的进行；Ca2+和Mg2+容易与地下水中的OH-生成沉淀，抑制反应进行，且Ca2+的抑制作用强于Mg2+。（4）在前期批实验的基础上，，利用石英砂为主要填充介质，构建有机玻璃柱反应装置，模拟水体流动状态下污染物的运移及修复过程，讨论树脂纳米铁用量、添加活性炭及不同地下水流速对铅污染地下水修复效果的影响。增加树脂纳米铁粉用量，可强化修复效果；添加活性炭促进污染物去除，但反应初期出水可溶性总铁浓度很高，可能引起地下水铁超标；地下水流速增大会降低污染物与树脂纳米铁的接触时间，因此降低污染物的去除率。
[Abstract]:Groundwater is an important component of water resources . It is an important resource to solve the industrial , agricultural and domestic water resources in China . In recent decades , economic and extensive development has made the development and utilization of natural resources increasing , the surface water pollution is serious , and the groundwater environment is polluted by different degrees . The heavy metal is one of the most important pollutants in groundwater . The heavy metal is one of the most important pollutants in groundwater . The zero - valent iron is simple and easy to obtain and has strong reactivity and can react with various pollutants , and the zero - valent iron treatment environment pollutant is a very active research field in recent years . In this paper , the feasibility of applying resin modified nano - iron to the remediation of lead - contaminated groundwater is discussed , and on the basis of the static batch experiment , the organic glass column reaction device is constructed , and the repairing effect under dynamic conditions is studied . ( 1 ) The resin nano - iron used in the experiment was characterized by SEM and XRD , and its morphology , main composition and stability were determined . The results show that the particle size is about 50 - 200 nm , and the main component is Fe ( 0 ) . The main component is Fe ( 0 ) . It has strong air stability and oxidation resistance , and can be stored stably for more than 60 days under the condition of exposure . ( 2 ) The effect of resin nano - iron on lead pollution groundwater was studied . The reaction kinetics and reaction mechanism were determined . The results showed that the removal of lead by resin nano - iron was consistent with the quasi - first order kinetic equation . ( 3 ) The effects of Cl - , SO _ 2 - , HCO _ 3 - , Ca 2 + , Mg 2 + on the groundwater of lead contaminated groundwater were studied . in that early stage of the reaction , the concentration of the pollutant is reduce greatly , and the pH buffering property of the HCO 3 - is also promote the reaction ; Ca2 + and Mg2 + are easy to react with OH in the groundwater to inhibit the reaction , and the inhibition of Ca2 + is stronger than Mg2 + . ( 4 ) On the basis of the previous batch experiment , using quartz sand as the main filling medium , the organic glass column reaction device is constructed to simulate the migration and repair of the pollutants in the water flowing state . The effect of the amount of the resin nano - iron , the addition of activated carbon and the flow rate of different groundwater on the groundwater restoration effect of lead pollution is discussed . The amount of the resin nano - iron powder is increased , the repairing effect can be enhanced ; the addition of activated carbon can enhance the removal of pollutants , but the water soluble total iron concentration in the early stage of the reaction is high , the contact time between the pollutants and the resin nano - iron can be reduced , and the removal rate of the pollutants is reduced .

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X523

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