【作者】 李晓；

【导师】 许玫英； 常向阳；

【作者基本信息】 广州大学 ， 环境工程（专业学位）， 2015， 硕士

【摘要】 海绵铁是一种以铁矿为基质经高温烧结筛选所得的廉价多孔水处理材料。它具有比表面积大、电化学富集性能强、物理吸附和絮凝性能好等特性而广泛应用于水处理领域。然而,在废水处理过程中海绵铁很容易被钝化而引起系统堵塞等问题。本研究利用实验室前期所获得的铁循环功能菌群,构建了铁循环功能菌群与海绵铁的耦合反应体系,从表观效应、微观变化与内在机制等层面,研究了铁循环功能菌群的解钝化作用及其强化海绵铁染料脱色的效果。取得以下主要研究结果:1、海绵铁的钝化作用:利用经灭菌和酸洗活化的海绵铁与40 mM橙黄Ⅱ溶液反应,分析比较反应体系中Fe2+的浓度和海绵铁表面结构特点,发现反应24 h后Fe2+的浓度为未钝化海绵铁的一半,脱色率仅在10%左右,且通过表面电镜扫描与X-射线衍射分析显示海绵铁表面被氧化膜(如:Fe2O3、Fe(OH)3、Fe3O4)包裹,说明此时的海绵铁发生了钝化作用。2、铁循环功能菌群的解钝化作用:铁循环功能菌群(IB)的添加可有效促进海绵铁染料脱色体系中Fe2+的溶出,抑制氧化膜的形成。尽管在铁循环功能菌群IB与海绵铁染料耦合反应体系中,细胞量与Fe2+呈显著的正相关(r=0.956,p<0.01),而pH与Fe2+释出浓度则呈显著的负相关(r=-0.927,p<0.01),但细胞量与Fe2+的溶出关系更加密切(Fe2+/pH r=-0.498,p=0.026;Fe2+/细胞量r=0.732,p<0.01),是解除海绵铁钝化作用的重要力量。当菌群IB以葡萄糖作为碳源时,生长最旺盛,Fe2+溶出的速率最大,为0.56 mg Fe2+/(L.h)。并且,随着初始pH的降低,菌群IB的解钝化效果也随之增强。当初始pH为5时,Fe2+的溶出速率最大,为1.10 mg Fe2+/(L.h)。而且,菌群IB在好氧,厌氧以及兼性条件下,都有解钝化海绵铁的能力。DGGE分析结果发现,反应前后各体系中菌群IB的微生物群落结构没有明显变化。3、铁循环功能菌群促进海绵铁的染料脱色效果:尽管菌群IB不具有脱色功能,但其添加可以显著强化已钝化海绵铁的染料脱色作用。在以葡萄糖为碳源、pH为5的厌氧条件下,该菌群对已钝化海绵铁的强化效果最好,脱色率分别为98.1%、98.7%、98.9%。综上所述,铁循环功能菌群IB可在好氧、厌氧、缺氧条件下抑制海绵铁表面氧化膜的形成,促进Fe2+的溶出速率,维持海绵铁的染料脱色活性。相关研究结果将为基于海绵铁的废水强化处理工艺提供科学理论指导。更多还原

【Abstract】 Sponge iron, which is made from iron ore through high heat sintering, is a kind of cheap and porous water treatment materials. It has been widely used in water treatment field due to its large specific surface area, strong enrichment of electrochemical performance and high physical adsorption and flocculation characteristics. However, sponge iron is easier to be passivated dueing the operation process, resulting in system block and treatment efficiency decrease. In this study, the depassivation and dye decolorization of sponge iron were performed by bioaugmentation with an iron-cycling microbial consortium enriched by our lab through constructing the microbial consortium-sponge iron combined reaction system and analyzing the the apparent effects, microscopic changes and the underlying mechanisms. The main results in this thesis were summarized as follows:1. The passivation of sponge iron:The sponge iron was passivation when the concentrations of Fe2+ were decreased 50%, the dye decolorization rates were only 10%, of the highest rate after 12 h performanceand in the reaction system with the sterilized sponge iron acid washed and activated. At this time, the surfaces of sponge iron were covered by oxidized film(such as Fe2O3, Fe(OH)3, Fe3O4) analyzed by scanning electron microscope and X-ray diffraction.2. The depassivation of iron-cycling microbial consortium: The additions of iron-cycling microbial consortium efficiently increased the the concentration of Fe2+ and inhibited the oxidized film formation in the sponge iron dye decolorization systems. Although significantly positive correlations(r=0.956, p<0.01) were between the biomass and the concentrations of Fe2+ and significantly negative correlations were between the pH and the concentration of Fe2+(r=-0.927, p<0.01) in the microbial consortium-sponge iron combined reaction system, closer relationship were observed between the biomass and the concentration of Fe2+(Fe2+/pH r = 0.498, p= 0.026; Fe2+/cell volume r =0.732, p<0.01), suggesting that microbial consortium play important role in the depassivation of sponge iron. When glucose was provided as the carbon sources, the microbial consortium IB reached the highest biomass and the highest Fe2+ concentration(0.67Fe2+/(L. h)) as well. With the increase of the initial pH, the depassivation efficiencies were increase. When the initial pH was 5, the highest of Fe2 + concentration, 1.32 mg Fe2+/(L. h) were obteined in this system. The microbial consortium IB could perform depassivation under aerobic, anaerobic or facultative condition.. Additionally, no significantly change was observed in the community structures of microbial consortium IB before and after the reaction in the different systems by DGGE analysis.3. The enhancement of sponge iron dye decolorization by the microbial consortium IB: Although the microbial consortium IB did not have the capacity for decolorization, the dye decolorization efficiencies of sponge iron could be increased when the consortim presented. The highest decolorizing rates, 98.1%, 98.7% and 98.9%, were obtained under the anaerobic condition with glucose as the carbon sources and pH 5.In conclusion, the microbial consortium IBcould inhibit the formation of oxidized film, accelerate Fe2+ dissolution, and mentain the decolorizing ability of sponge iron under aerobic, anaerobic and facultative conditions. These results will provide important scientific basis for the wastewater treatment usring sponge iron technologies..更多还原