微波辅助法快速合成氧化石墨及磁性还原氧化石墨烯用于环境水样中三嗪类除草剂的萃取

发布时间：2018-07-08 14:30

  本文选题：微波辅助法 + 氧化石墨　； 参考：《吉林大学》2015年硕士论文

【摘要】：近年来，石墨烯及石墨烯基复合材料成为研究的热点。研究的内容主要是合成方法的改进和石墨烯基复合材料应用的拓展。在合成方法上，利用氧化石墨合成石墨烯是成本最低的一种方法，适合大批量生产。因此，氧化石墨合成方法的改进也成为时下研究的重点。 本文对氧化石墨的快速合成方法进行了探索，之后利用合成的氧化石墨制备了磁性还原氧化石墨烯并将其应用于水样中三嗪类除草剂的富集，结合高效液相色谱-串联质谱法对其进行了检测，实现了环境水样中三嗪类污染物的快速萃取、富集、分离和检测。具体的研究内容分为以下三个方面： 1改进了氧化石墨的合成方法，对比改进的Hummers法，不但减少了硫酸的用量，而且不使用亚硝酸钠，避免了氮氧化物有毒气体的释放。利用微波加热法，将反应时间从12h缩短至30s，获得了氧化程度较高的氧化石墨。该方法具有操作简单，合成效率高的特点。另外，为了改进常压微波辅助法在合成过程中有酸雾释放，反应条件不易控制等缺点，利用高压微波法合成了氧化石墨。在70℃的反应温度下制备了氧化石墨，反应过程比常压微波辅助法更加温和。对这两种方法合成的氧化石墨进行了表征，结果表明产物的氧化程度较好。 2用溶剂热还原法成功地合成了磁性还原氧化石墨烯（magnetic reducedgraphene oxide，M-RGO），并对其做了详细的表征。表征结果表明磁性粒子主要由Fe3O4组成，具有很好的磁性（饱和磁化强度70emu g-1）。通过扫描电镜图可以看出磁性还原氧化石墨烯具有很好的形貌，Fe3O4粒子呈球形，粒径为500nm左右，均匀的分布在石墨烯片层上。这种石墨烯基复合材料对三嗪类除草剂有强烈的吸附作用，在水质净化和水质分析上有很好的应用前景。 3建立了用磁性还原氧化石墨烯作为吸附剂结合高效液相色谱-串联质谱法检测水中三嗪类除草剂的分析方法。磁性还原氧化石墨烯对含苯环的小分子有很好的吸附作用，同时磁性粒子对还原氧化石墨烯的修饰能使其快速从复杂体系中分离。用磁性还原氧化石墨烯做吸附剂富集水中三嗪类除草剂，富集倍数可达500倍。优化了萃取条件，吸附剂的量为70mg，吸附时间10min，上样pH为7，洗脱溶剂为丙酮，洗脱体积为4mL，在最佳萃取条件下，采用高效液相色谱-串联质谱法进行分析，方法的检出限为0.16-0.52ng L-1，回收率在72-96%之间。运用该方法成功地检测了长春市内三个环境水样中的三嗪类除草剂，，结果令人满意。
[Abstract]:In recent years, graphene and graphene matrix composites have become the focus of research. The main contents of the research are the improvement of synthesis method and the application of graphene-based composites. The synthesis of graphene from graphite oxide is the lowest cost and suitable for mass production. Therefore, the improvement of graphite oxide synthesis method has also become the focus of current research. In this paper, the rapid synthesis method of graphite oxide was explored, and then the magnetic reductive graphene oxide was prepared by using the synthesized graphite oxide and applied to the enrichment of triazine herbicides in water samples. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS) was used to detect the triazines in environmental water. The rapid extraction, enrichment, separation and detection of triazines in environmental water samples were achieved. The specific research contents are as follows: 1 the synthesis method of graphite oxide has been improved. Compared with the improved Hummers method, not only the amount of sulfuric acid is reduced, but also sodium nitrite is not used. The release of noxious nitrogen oxide gas is avoided. Graphite oxide with high oxidation degree was obtained by microwave heating and the reaction time was shortened from 12 h to 30 s. This method has the characteristics of simple operation and high synthesis efficiency. In addition, graphite oxide was synthesized by high pressure microwave method in order to improve the acid mist release in the synthesis process, and the reaction conditions were not easy to control. Graphite oxide was prepared at 70 鈩

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