生成动力学对含砷水铁矿矿物学特征和微生物还原活性的制约

发布时间：2018-06-15 15:30

  本文选题：水铁矿 + 砷　； 参考：《合肥工业大学》2015年硕士论文

【摘要】：由于具有高比表面积和良好的阴、阳离子固持性能,水铁矿(Fe5HO8·4H2O)作为一种高效环境材料受到广泛关注,其中一个重要应用方向就是运用水铁矿处理含As水体,但是水铁矿的低稳定性在一定程度上限制了其应用。本文拟通过改变水铁矿的合成速率和As含量各异的水铁矿,来制得不同As含量和结晶程度的水铁矿,藉此探讨了水铁矿生成动力学对其矿物学特征和对As固定能力的影响；同时,开展含砷水铁矿在自然条件下的老化实验和在厌氧微生物异化铁还原细菌(DIRB)作用下的还原分解实验,探讨水铁矿的生成条件(动力学和As添加量)对其转化和分解的影响。研究对深化水铁矿矿物学理论及优化水铁矿的环境工程应用条件等方面有比较重要的意义。水铁矿合成实验结果表明,低的OH-添加速率会导致Fe(OH)x(3-x)+基团聚合、脱水并生成与Fe连接的桥氧键,桥氧键的存在使得具有一定结晶度的6L-Fh、针铁矿和赤铁矿可以直接从溶液中沉淀。H2AsO4-会替代OH-的功能,但由于二者理化性质方面的差异,As参与下形成的水铁矿结晶度降低。中性条件下水铁矿的老化为固相转化,结晶度越好的初始产物转化越彻底。生成速率越慢、As添加量越少的水铁矿中的结晶程度越好,表现在6L-Fh越多。自然老化实验结果表明,中性条件下水铁矿通过固相转变向其它矿物转化,生成速率越慢、As添加量越少、结晶度越好的水铁矿转化越快。转化产物主要为针铁矿和赤铁矿,粒径随着As添加量的减少和合成时间的延长而从5nm～20nm变化。含As水铁矿转化过程中会导致少量As释放,As的释放量受合成过程中As添加量影响较小,受生成速率影响较大,生成速率越慢,As释放量越小。微生物实验结果表明,DIRB的能够有效溶解水铁矿,当水铁矿表面的吸附节点不足以固持As时,As就会释放进入溶液中；生成速率对水铁矿的结晶程度影响很大,生成速率越慢,水铁矿结晶度越高,分解速率越慢,As释放量越少；As添加量越高,水铁矿结晶度越差,分解速率越快,As释放量也越多。该研究表明,环境工程中应用水铁矿共沉淀法处理含As废水时,适当降低共沉淀速率并保持水铁矿处于氧化条件下有助于强化As的固定和抑制水铁矿转化或分解过程中As的释放。
[Abstract]:Because of its high specific surface area, good cation fixation and high specific surface area, water ore Fe5HO84H _ 2O has attracted wide attention as a kind of efficient environmental material. One of the important application directions is to use water ore to treat as water body. But the low stability of water ore restricts its application to some extent. In this paper, the hydrothermal ore with different as content and different synthesis rate is prepared by changing the synthesis rate and the content of as, and the effect of hydrothermal formation kinetics on its mineralogical characteristics and as fixation ability is discussed. At the same time, the aging experiments of arsenic-containing water ore under natural conditions and the reduction and decomposition experiments under the action of anaerobic microorganism dissimilatory iron reducing bacteria (DIRB) were carried out. The effects of the formation conditions (kinetics and as addition) of hydrothermal ore on its transformation and decomposition are discussed. The study is of great significance in deepening the mineralogical theory of water ore and optimizing the environmental engineering application conditions of water ore. The experimental results of hydrothermal synthesis show that the low OH- addition rate leads to the polymerization, dehydration and formation of bridged oxygen bonds connected with Fe. Because of the existence of bridging oxygen bond, the crystallinity of 6L-Fh with a certain degree of crystallinity can be replaced by the precipitation of goethite and hematite directly from the solution. However, the crystallinity of water ore formed with the participation of as is decreased due to the difference of their physical and chemical properties. The aging of iron ore in neutral condition is solid phase transformation, and the better the crystallinity of the initial product is, the more thorough the transformation is. The higher the rate of formation, the better the degree of crystallization in the pyrite with less addition of as, and the more 6L-Fh. The results of natural aging test show that the slower the formation rate of iron ore is, the less the amount of as is added, and the faster the transformation of hydrothermal ore with better crystallinity can be achieved by the transformation of iron ore into other minerals through solid phase transformation under neutral conditions. The transformation products are mainly goethite and hematite. The particle size changes from 5nm~20nm with the decrease of as addition and the prolongation of synthesis time. In the process of transformation, the amount of as released from as is less affected by the amount of as added in the process of synthesis, but by the rate of formation, and the slower the rate of formation is, the smaller the release of as is. The results of microbial experiments show that DIRB can dissolve water ore effectively, and when the adsorption node on the surface of water ore is not enough to hold as, it will release as into the solution, and the rate of formation has a great influence on the crystallization degree of water ore, and the rate of formation is slower. The higher the crystallinity, the slower the decomposition rate is, and the lower the amount of as is added, the worse the crystallinity is, and the faster the decomposition rate is, the more as released. The results show that the coprecipitation method of water and iron ore in environmental engineering is used to treat wastewater containing as. Decreasing the coprecipitation rate and keeping the water ore in the oxidation condition can help to strengthen the fixation of as and inhibit the release of as during the process of transformation or decomposition.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;P579

【相似文献】

中国期刊全文数据库 前3条

1 王小明;孙世发;刘凡;谭文峰;胡红青;冯雄汉;;铁(氢)氧化物悬液中磷酸盐的吸附-解吸特性研究[J];地球化学;2012年01期

2 王维;王晓丽;赵丽媛;王利香;;掺杂水铁矿对黄河表层沉积物吸附Cd的影响[J];内蒙古师范大学学报(自然科学汉文版);2011年06期

3 ;[J];;年期

中国重要会议论文全文数据库 前2条

1 王小明;刘凡;谭文峰;邱国红;冯雄汉;;模拟环境中水铁矿形成的几个因素探讨及对磷的吸附解吸特性[A];中国矿物岩石地球化学学会第13届学术年会论文集[C];2011年

2 刘青松;Jos忮 Torrent;;水铁矿的环境意义[A];中国地球物理·2009[C];2009年

中国重要报纸全文数据库 前1条

1 记者　张玺;包头透水铁矿被困矿工生还希望渺茫[N];工人日报;2007年

中国博士学位论文全文数据库 前1条

1 王小明;几种亚稳态铁氧化物的结构、形成转化及其表面物理化学特性[D];华中农业大学;2015年

中国硕士学位论文全文数据库 前4条

1 郭沛;还原条件下水铁矿对钙磷形态的影响[D];华中农业大学;2015年

2 李仕伟;水铁矿对酸性土壤中硝化作用的影响[D];西南大学;2015年

3 殷矫军;生成动力学对含砷水铁矿矿物学特征和微生物还原活性的制约[D];合肥工业大学;2015年

4 张伟;水铁矿对镉的吸附共沉淀研究[D];成都理工大学;2014年

，

本文编号：2022533