碳纳米管介导水中典型有机污染物非生物转化的研究

发布时间：2018-04-18 00:21

  本文选题：碳纳米管 + 硝基苯　； 参考：《中国科学技术大学》2017年硕士论文

【摘要】：碳纳米管是一种新型的碳纳米材料,它具有大的表面积、良好的导电性、高度的多孔结构、丰富的含氧官能团等特点而被用于航空航天、汽车制造、医疗保健、环境保护等领域。虽然碳纳米管早已被用于环境领域,但人们对碳纳米管在污染控制方面的研究还仅限于它的吸附能力,缺少其它方面的相关研究。本课题以硝基苯和偶氮染料两种典型的水体污染物为研究对象,以环境中常见的还原性物质硫化钠为还原剂,探讨了碳纳米管介导水体污染物非生物降解的可能性,考察了不同因素对碳纳米管介导污染物降解的影响,研究了碳纳米管介导偶氮染料降解和其结构之间的构效关系,并探讨了碳纳米管的作用机理。本文的研究内容和主要结论如下:1、评估了碳纳米管介导污染物非生物降解的可能性。研究结果表明碳纳米管的存在可以极大的促进硝基苯和偶氮染料的非生物降解。硝基苯降解的伪一级动力学常数由(3.44±0.26)×10-3 h-1提高到(1.40±0.08)×10-2h-1。未加碳纳米管前甲基橙几乎不降解,橙黄Ⅰ在经过100 min反应后降解率仅为15.9%,当加入碳纳米管后甲基橙在50 min时就已经完全脱色,橙黄Ⅰ也在100 min时完全脱色。2、研究了不同表面改性对碳纳米管介导污染物非生物降解的影响。研究结果表明,经过退火处理后的碳纳米管具有更好的催化能力,尤其是400℃退火处理后,碳纳米管介导硝基苯降解的伪一级动力学速率常数提高5倍以上。然而,氩等离子辐射处理对碳纳米管介导污染物非生物降解影响甚微。3、考察了多种因素对碳纳米管介导硝基苯非生物降解的影响。研究结果表明,碳纳米管介导硝基苯降解的最佳pH为7～8之间,腐殖酸的存在会抑制碳纳米管介导硝基苯降解,碳纳米管介导硫化物化学还原降解硝基苯的表观活化能为29.0kJ mol-1,碳纳米管介导硝基苯非生物降解所需硫化钠最低浓度为0.98 mM。4、探究了偶氮染料不同构型对碳纳米管介导偶氮染料非生物降解的影响。研究表明,不同构型对碳纳米管介导偶氮染料非生物降解影响很大,吸电子基团例如羧基、硝基、磺酸基等能够促进偶氮染料的还原,而斥电子基团例如羟基、氨基等会抑制偶氮染料的还原。取代基所处的位置也对碳纳米管介导偶氮染料非生物降解影响很大,羧基处于邻位相对于其他位置对偶氮染料还原具有促进作用,羟基处理邻位对偶氮染料还原具有抑制作用。
[Abstract]:Carbon nanotubes (CNTs) are a new type of carbon nanomaterials with large surface area, good electrical conductivity, high porous structure, rich oxygen functional groups and so on, which have been used in aerospace, automobile manufacturing, medical care, etc.Environmental protection and other fieldsAlthough carbon nanotubes (CNTs) have been used in the field of environment for a long time, the study of carbon nanotubes in pollution control is limited to its adsorption ability and lack of other related research.In this paper, two typical water pollutants, nitrobenzene and azo dyes, were studied. The possibility of non-biodegradation of water pollutants mediated by carbon nanotubes (CNTs) was discussed with sodium sulphide, a common reducing substance in the environment, as the reducing agent.The effects of different factors on the degradation of pollutants mediated by carbon nanotubes (CNTs) were investigated. The structure-activity relationship between CNTs mediated degradation of azo dyes and their structures was studied, and the mechanism of action of CNTs was also discussed.The research contents and main conclusions are as follows: 1. The possibility of non-biodegradation of pollutants mediated by carbon nanotubes was evaluated.The results show that the existence of carbon nanotubes can greatly promote the non-biodegradation of nitrobenzene and azo dyes.The pseudo-first-order kinetic constant of nitrobenzene degradation was increased from 3.44 卤0.26 脳 10-3 h ~ (-1) to 1.40 卤0.08 脳 10 ~ (-2) h ~ (-1).There was almost no degradation of methyl orange without carbon nanotubes, and the degradation rate of orange I was only 15.9 after 100 min reaction. When adding carbon nanotubes, methyl orange was decolorized completely at 50 min.Orange 鈪，

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