不同性质和结构的悬浮剂对纳米碳管悬浮及吸附性能的影响

发布时间：2018-04-24 20:45

  本文选题：纳米碳管 + DOM结构　； 参考：《昆明理工大学》2016年硕士论文

【摘要】：作为重要的工程纳米材料,纳米碳管(Carbon Nanotubes, CNTs)由于其独特的物化性质(机械强度、导电性和储氢能力等),在人类生产生活中具有应用广泛。由于对CNTs应用的不断增加,使其不可避免地进入环境中,对生态环境产生难以预料的影响。之前很多研究关注了溶解性有机质(Dissolve Organic Matter, DOM)对CNTs环境行为和风险的影响,发现DOM可以促使CNTs悬浮,而CNTs一旦悬浮分散,其大量暴露的表面积与污染物会产生强烈的相互作用。由于处于纳米尺度,悬浮CNTs可能携带污染物直接进入生物体内,从而对生物体产生毒性,加之其较大的迁移性,加剧了悬浮CNTs及其吸附的有机污染物的环境风险。然而,目前对不同机制下悬浮的CNTs对有机污染物的吸附特征关注还不够,对不同性质和结构的悬浮剂悬浮CNTs的机制研究也很少。因此,本研究选取单宁酸(Tannic Acid, TA)、没食子酸(Gallic Acid, GA)和十二烷基苯磺酸钠(Sodium Dodecylbenzenesulfonate, SDBS)为三种不同性质和结构的悬浮剂,研究了不同性质的悬浮剂在CNTs上的吸附行为,明确了不同性质的悬浮剂分散CNTs的机制；以双酚A (Bisphenol A, BPA)为污染物,研究了不同性质悬浮剂悬浮的CNTs对有机污染物的吸附性能。得到如下结果：1.在三种悬浮剂浓度到达TA和SDBS的达临界胶束浓度(critical micellar concentrations, CMC)前,CNTs悬浮量的顺序为：TA SDBS GA。结合TA、 SDBS和GA三种悬浮剂在CNTs上的吸附量,发现尽管CNTs的悬浮受到悬浮剂在CNTs上吸附量的影响,但悬浮剂的性质和结构等是控制CNTs悬浮量的最重要因素。因此,TA、SDBS和GA在CNTs上的吸附是各种机理共同作用的结果,其中最重要的控制因素是空间位阻作用,其他还包括憎水性作用、π-π电子供受体作用、氢键作用等。TA、SDBS口GA形成的空间位阻作用是控制纳米碳管悬浮的主要机理。2.研究发现TA、SDBS和GA三种悬浮剂悬浮的CNTs吸附BPA的量的顺序与TA、SDBS和GA三种悬浮剂在CNTs上造成的空间位阻作用的强弱顺序相反。此外,结合对BPA在TA、SDBS和GA三种悬浮剂悬浮的CNTs上吸附机理的分析,可以推断空间位阻作用是控制BPA在CNTs上吸附的最主要作用。当到达悬浮剂的CMC时,吸附在CNTs表面的悬浮剂对BPA的增溶效应导致BPA在CNTs上的吸附增加。
[Abstract]:As an important engineering nanomaterials, carbon nanotubes (CNTs) have been widely used in human production and life due to their unique physical and chemical properties (mechanical strength, electrical conductivity and hydrogen storage capacity). Because of the increasing application of CNTs, it inevitably enters into the environment and has unpredictable influence on the ecological environment. Previous studies have focused on the effects of dissolved organic matter Dissolve Organic matter (Dom) on the environmental behavior and risk of CNTs. It has been found that DOM can promote the suspension of CNTs, while once suspended, the surface area exposed to CNTs strongly interacts with pollutants. Because of its nanometer scale, suspended CNTs may carry pollutants directly into the body of organisms, thus causing toxicity to organisms and its large mobility, which increases the environmental risk of suspended CNTs and its adsorbed organic pollutants. However, little attention has been paid to the adsorption characteristics of organic pollutants by suspended CNTs under different mechanisms, and the mechanism of suspended CNTs with different properties and structures has been seldom studied. Therefore, in this study, Tannic acid, Taci, Gallic acid (GA) and sodium dodecyl benzenesulfonate (SDBs) were selected as three kinds of suspensions with different properties and structures, and the adsorption behaviors of different suspensions on CNTs were studied. The mechanism of dispersion of CNTs with different suspensions was clarified, and the adsorption properties of CNTs suspended with different properties for organic pollutants were studied by using bisphenol A and bisphenol A as pollutants. Get the following result: 1. Before the concentration of three suspensions reaches the critical micelle concentration of TA and SDBS, the order of suspension amount of micellar is: 1 TA SDBS GA. Combined with the adsorption capacity of TAA, SDBS and GA on CNTs, it was found that, although the suspension of CNTs was affected by the amount of adsorbent adsorbed on CNTs, the properties and structure of suspensions were the most important factors controlling the suspension amount of CNTs. Therefore, the adsorption of TASDBS and GA on CNTs is the result of various mechanisms, among which the most important controlling factor is steric hindrance, and other factors include hydrophobicity, 蟺-蟺 electron donor receptor. The main mechanism of controlling the suspension of carbon nanotubes is the steric hindrance formed by the formation of GA at the mouth of TAA SDBs by hydrogen bonding. It is found that the order of the amount of BPA adsorbed by CNTs suspended by TASDBS and GA is opposite to the order of the spatial steric resistance caused by TASDBS and GA on CNTs. In addition, based on the analysis of the adsorption mechanism of BPA on CNTs suspended by TASDBS and GA, it can be concluded that the steric hindrance is the most important role in controlling the adsorption of BPA on CNTs. When the CMC reached the suspension, the solubilization effect of the suspension adsorbed on the surface of CNTs resulted in the increase of the adsorption of BPA on CNTs.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ127.11;TB383.1

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