核壳结构铁纳米线去除溴酸盐及阿特拉津的研究

发布时间：2018-03-31 21:51

  本文选题：Fe@Fe_2O_3纳米线　切入点：溴酸盐　出处：《华中师范大学》2015年硕士论文

【摘要】：经济的飞速发展改善了人们的生活,但也破坏了我们的生存环境。寻求高效绿色的环境治理手段已成为环保工作者关注的焦点。铁是一类活泼的过渡金属元素,在地壳中含量丰富。在众多的环境治理途径中,铁作为一类环境友好的材料引起了环保工作者的广泛关注。零价铁具有较强的还原性,能直接还原去除环境中的污染物,使污染物危害或毒性减弱；同时,零价铁还能活化空气中的氧气,通过产生活性氧物种氧化降解甚至完全矿化去除有机污染物。本论文合成了核壳结构铁纳米线材料,研究了这种特殊结构纳米零价铁去除水中典型污染物溴酸盐和阿特拉津的效率和机理。论文的主要研究内容如下：1.溴酸盐是高级氧化技术特别是臭氧氧化技术消毒饮用水过程产生的消毒副产物,它被国际癌症组织定义为一种2B级的潜在致癌物质。本论文讨论了在中性pH条件下核壳结构Fe@Fe2O3纳米线对溴酸盐的去除,并探究了反应过程中间产物以及体系中亚铁的作用；另外还探究了溶解氧对于溴酸盐去除的影响。结果显示具有核壳结构Fe@Fe2O3纳米线能在90 min内将溴酸盐(BrO3-,1 mg/L)100%还原为溴离子(Br-),商品化Fe0对溴酸盐的去除率为0%。中间产物测定显示HBrO/BrO是一种重要的中间产物。通过邻二氮菲捕获亚铁实验发现,亚铁对于溴酸盐的去除贡献了34%。通过对比空气、氩气气氛下溴酸盐的去除效率,发现氩气条件下溴酸盐的去除速率是空气条件下的2.56倍。活性氧物种的捕获实验结果表明：·02-、H2O2被捕获后溴酸盐的去除分别被抑制了82.4%、31.5%,而-OH被捕获后,去除速率提高了1.19倍。结合XRD、SEM、XPS表征铁纳米线去除溴酸盐前后的结构、形貌和组成成分分析,提出了核壳结构铁纳米线去除溴酸盐的机理,并且去除过程的效率是高度依赖于表面亚铁以及氧气。2.阿特拉津是世界范围使用的一种三嗪类除草剂,对动物以及人体的内分泌产生极大的干扰。本文向零价铁活化分子氧体系引入镍离子改变阿特拉津常规的去除途径,结果显示Fe@Fe2O3/Ni(Ⅱ)/air降解阿特拉津的速率是Fe@Fe2O3/air体系的11.97倍。通过Fe@Fe2O3/Ni(Ⅱ)/air体系中间产物的分析可知阿特拉津降解首先是脱氯上氢,其次是脱烷基、侧链氧化。阿特拉津脱烷基后的产物CAAT、AAT降解特性研究结果以及AAT降解产物的氢谱和中间产物拉曼光谱分析,证实阿特拉津在Fe@Fe2O3/Ni(Ⅱ)/air体系中三嗪环开环降解。
[Abstract]:The rapid development of the economy has improved people's lives, but also destroyed our living environment. The search for efficient and green means of environmental management has become the focus of attention of environmentalists. Iron is a kind of lively transition metal element. Iron, as a kind of environment-friendly material, has aroused the widespread concern of environmental protection workers in many environmental control ways. Zero valent iron has strong reductivity and can directly reduce and remove pollutants in the environment. At the same time, zero-valent iron can activate oxygen in air and remove organic pollutants by producing active oxygen species, even completely mineralized. In this paper, core-shell structure iron nanowire materials were synthesized. The efficiency and mechanism of removal of bromate and atrazine from water by nanometer zero-valent iron with this special structure were studied. The main contents of this paper are as follows: 1. Bromate is an advanced oxidation technology, especially ozone oxidation technology. Disinfection by-products from the process of toxic drinking water, It is defined by the International Cancer Organization as a potential carcinogen of class 2B. In this paper, the removal of bromate by core-shell Fe@Fe2O3 nanowires at neutral pH was discussed, and the effects of intermediate products in the reaction process and iron in the system were investigated. The effect of dissolved oxygen on the removal of bromate was also investigated. The results showed that the Fe@Fe2O3 nanowires with core-shell structure could reduce the bromate BrO3-1 mg / L ~ (100%) to Br-N in 90 min, and the removal rate of bromate by commercial Fe0 was 0%. The results show that HBrO/BrO is an important intermediate product. Iron contributes 34% to the removal of bromate. By comparing the removal efficiency of bromate in air and argon, It was found that the removal rate of bromate in argon was 2.56 times higher than that in air. The experimental results showed that the removal of bromate was inhibited by 82.4% and 31.5% respectively after the capture of H2O2 and -OH. The removal rate was increased by 1.19 times. The structure, morphology and composition of iron nanowires before and after removal of bromate were characterized by XRDX SEMX XPS, and the mechanism of removing bromate from core-shell structure iron nanowires was put forward. And the efficiency of the removal process is highly dependent on surface ferrous and oxygen. Atrazine is a triazine herbicide used worldwide. In this paper, nickel ion was introduced to the zero-valent iron activated molecular oxygen system to change the conventional removal pathway of atrazine. The results showed that Fe _ 2O _ 3 / Ni (鈪，

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