羧基化磁性载铁有序介孔碳快速吸附农药2，4-二氯苯氧乙酸的研究

发布时间：2018-02-24 09:47

  本文关键词： 农药 有序介孔碳 羧基化 磁性 2 4-二氯苯氧乙酸 吸附　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：农药是现代农业生产必不可少的一部分,它极大地提高了粮食生产的产量。但是随着农药的广泛应用,农药已经分布于世界各地并且在地球上任何水体中都可以检测得到农药的存在。此外,农药的衰减周期很长而且通过自然界自身难以降解,进而通过生物链不断向顶端生物体内富集,导致了农药的环境污染问题和中毒事件频频发生,导致了生态平衡被破坏,因此人们也逐渐地在关注农药对环境的污染问题和对人类健康的影响。长期暴露在含有农药的环境中会对人和动物产生较为严重的不利影响,甚至产生致癌作用。因此,农药的处理是迫在眉睫的事情。本研究制备了羧基化磁性载铁有序介孔碳,并对其吸附农药2,4-D的过程及机理进行了调查研究。羧基化磁性载铁有序介孔碳(Fe/OMC)被成功地制备,并且应用于吸附来自废水中的2,4-二氯苯氧乙酸(2,4-D)。成功合成的吸附剂拥有高度有序性、大的比表面积和孔容和良好的磁性分离等特性。2,4-D的吸附量随着初始浓度和接触时间的增加而增加,然而却随着p H和温度的增加而减少。p H为3时Fe/OMC对2,4-D的吸附量到达最大值,这也就意味着对2,4-D的吸附过程高度依赖于溶液的p H。在120 min内达到对2,4-D的吸附平衡,并且随着2,4-D的初始浓度从100增加到500 mg/L,平衡时的吸附量从99.38增加到310.78 mg/g。更重要的是在仅仅5 min内,吸附量就可以达到平衡时吸附量的97%。随着反应温度从30℃增加到50℃,Fe/OMC对2,4-D的吸附容量从270.60 mg/g降低到256.38 mg/g,这也意味着Fe/OMC对2,4-D的吸附过程是一个放热过程。动力学和等温吸附的研究表明,准二阶动力学和Langmuir等温模型与吸附数据更吻合。吸附热力学模型证明了Fe/OMC对2,4-D的吸附主要是物理吸附过程,并且是可行的、自发的。Fe/OMC的吸附效率在高的2,4-D的初始浓度下经过六次循环之后仍然能维持较高的水平,这也意味着Fe/OMC拥有一个很好地再生性能和重复性。这些结果意味着,Fe/OMC对于快速吸附2,4-D和进一步防止2,4-D扩散有一个相当不错的潜力。
[Abstract]:Pesticide is an indispensable part of modern agricultural production. It has greatly increased the yield of grain production. But with the wide application of pesticides, Pesticides have been distributed all over the world and can be detected in any water body on Earth. In addition, pesticides have a long decay period and are difficult to degrade through nature itself. Then through the biological chain to the top of the biological enrichment, leading to pesticide environmental pollution problems and poisoning incidents occurred frequently, resulting in the destruction of the ecological balance, As a result, people are gradually paying attention to the pollution of pesticides to the environment and the impact on human health. Prolonged exposure to pesticides may have a more serious adverse effect on people and animals and even produce carcinogenic effects. In this study, carboxylated magnetic ordered mesoporous carbon containing iron was prepared, and the process and mechanism of its adsorption of 2n4-D were investigated. The carboxylated magnetic magnetic ordered mesoporous carbon containing iron (Fe / O) was successfully prepared. The adsorbents successfully synthesized have a high degree of order, and have been applied to the adsorption of 2o 4- dichlorophenoxy acetic acid (DTAA) from waste water. With the increase of initial concentration and contact time, the adsorption capacity of 2.4-D increases with the increase of initial concentration and contact time, but decreases with the increase of pH and temperature. The adsorption capacity of 24-D for 3:00 Fe/OMC reaches the maximum value with the increase of pH and temperature. This means that the adsorption process of 2H4-D is highly dependent on the pH of the solution. The adsorption equilibrium of 2H4-D is achieved within 120 min. And with the initial concentration of 24-D increasing from 100 to 500 mg / L, the adsorption capacity at equilibrium increases from 99.38 to 310.78 mg / g. More importantly, in just 5 min, With the increase of reaction temperature from 30 鈩，

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