基于辐照技术的功能性纳米材料制备及其在污染控制中的应用

发布时间：2018-05-01 20:05

本文选题：高能电子束 + 纳米材料　；参考：《中国科学技术大学》2017年博士论文

【摘要】：工业污水的违规排放以及农药、化肥的滥用成为环境污染的主要来源,严重危害了人类的健康。纳米材料具备优异的电、力、磁、光学和化学性能,经过功能化修饰的纳米粒子又被赋予了许多新的优良属性,因此在化工、电子、生物、医学等多个领域都有广泛的应用前景。近年来,科学家们将纳米技术应用于环境污染治理领域,并对环境污染物的去除取得了很好的效果。传统的纳米材料制备方法繁杂、成本高、耗时长,而高能电子束辐照技术具有高效便捷并可以大批量处理反应物的优点,因此在纳米材料的制备方面受到越来越多的关注。本论文主要基于高能电子束辐照技术对纳米材料进行辐照改性,制备出不同的功能化纳米材料,并将其应用于环境污染物的去除领域中。本论文的主要研究内容如下:1.接触法合成硫酸通常使用硅藻土作为钒催化剂载体,而天然硅藻土的孔径小、堵塞严重,降低了反应物在孔道内的传质速度。在论文的第二章中,我们利用高能电子束辐照技术对天然硅藻土进行辐照处理,改善了硅藻土的孔径分布,从而提高了硅藻土作为催化剂载体的品质。研究结果表明,高能电子束在辐照硅藻土的过程中所具有的溅射效应、库伦爆炸和热效应可以有效增大硅藻土的孔径。对改性前后的硅藻土进行比表面积分析,并对催化剂的催化性能进行测试,结果表明改性后的硅藻土孔道被疏通,因此具有较大的孔径,有利于提高硫酸合成过程中的二氧化硫与空气在硅藻土孔道中的传质速度和反应物之间的接触面积,从而提高了硅藻土在硫酸合成过程中作为催化剂载体的催化效率。2.传统的叶面肥在施肥后只有小部分可以被植物吸收,而未被利用的大部分肥料则是随着雨水冲刷、淋溶和蒸发作用进入水体、空气和土壤中,不仅造成了肥效的流失,还会导致严重的环境污染,因此需要制备出在植物叶片上附着能力强、利用率高的新型叶面肥。在论文的第三章中,我们利用高能电子束辐照技术对天然纳米材料-凹凸棒土进行改性,提高其分散性和比表面积。然后再将秸秆灰与改性后的凹凸棒土按一定质量比例进行复合,从而制备出一种新型的叶面肥控失剂。结果表明,所制备的叶面肥控失剂具有多孔微纳网络结构和较大的比表面积,可以吸附大量的氮肥,并将其固定在自身的网络结构体系中。在叶面肥的施肥过程中,此网络结构可以被植物叶片上的微观结构所阻挡,从而保留在叶片上,不易流失,提高了叶面肥的利用率。3.铁在植物的生长发育过程中必不可少,如果出现缺铁情况则会导致作物出现黄叶病,从而影响作物的品质和产量。与根施铁肥相比,铁元素叶面肥能快速补充二价铁离子,维持植物的正常生长发育。而叶面肥的易流失和亚铁离子的不稳定性是降低铁元素叶面肥肥效的关键问题之一。因此,需要制备出一种新型的铁元素叶面肥,使其能够有效地固定亚铁离子,延缓其氧化速率,提高亚铁离子的利用效率。在论文的第四章内容中,我们将微晶纤维素氧化改性,得到表面含有大量羧基的纤维素,而羧酸根与二价铁离子之间的静电作用能够固定二价铁离子,从而形成两者的复合物。再向复合物体系中加入改性的凹凸棒土,最终制备出控释铁元素叶面肥。结果表明,该方法可以有效增强铁元素在作物叶片上的附着能力并延缓亚铁离子的氧化速率。此外,利用羧酸根对pH的敏感性,在酸性条件下会与氢离子结合从而解离出二价铁离子,因此可以通过调节溶液的pH值来控制铁元素的释放量,提高叶面肥的利用效率。该方法所制备的控释型铁元素叶面肥可以满足作物不同生长时期对铁元素的需求,促进作物平衡生长。4.太阳光中只有2%-5%的紫外光,导致了以紫外光激发的光催化剂的效率较低,限制了光催化剂在污染物降解领域中的应用。因此,制备出可以利用可见光的光催化剂来降解有机污染物受到越来越多的关注。论文的第五章提供了一种基于高能电子束辐照技术制备的可以降解有机磷农药的光催化剂(MnO2/C复合物)的制备方法。高能电子束辐照水溶液,能够产生水合电子、电子和氢自由基等具有还原性粒子,可以还原MnO4-,制备出MnO2纳米粒子。同时,高能电子束具有的热效应和溅射效应还可以使氧化石墨表面变得更加粗糙,通过MnO2表面羟基与石墨表面的含氧基团之间形成的氢键将MnO2纳米颗粒固定在石墨表面。实验结果表明,该方法制备的MnO2/C复合材料具有优异的分散性和光催化属性,可以在太阳光的激发下将草甘膦降解为无毒的无机小分子。5.医疗废弃物的违规处理导致环境中出现大量的抗生素残留,导致细菌耐药性的增加,严重危害人类的健康。在论文的第六章中,我们通过高能电子束辐照技术直接处理医疗废弃物中的抗生素残留,将抗生素在原位进行辐照降解,并探讨了抗生素的降解效率受高能电子束辐照剂量、抗生素溶液的初始浓度、自由基清除剂以及其他共存物质的影响。研究结果表明,高能电子束辐照对阿莫西林、氧氟沙星和头孢拉定的降解效率分别为97.02%,97.61%和96.87%。高效液相色谱-质谱和红外光谱分析表明,阿莫西林,氧氟沙星和头孢拉定经过降解后产生的降解产物相似,均为直链烷烃和无机物小分子。此外,在本章中还对抗生素的降解机理进行了进一步的探讨,研究发现,在电子束辐照降解抗生素的过程中,·OH起主导作用。
[Abstract]:The illegal emission of industrial sewage and the abuse of pesticides and chemical fertilizers have become the main source of environmental pollution, which seriously endangers human health. Nanomaterials have excellent electrical, force, magnetic, optical and chemical properties. The functionalized nanoparticles have been given many new excellent properties, so they are in chemical, electronic, biological, medical, and so on. In recent years, scientists have applied nanotechnology to the field of environmental pollution control, and have achieved good results in the removal of environmental pollutants. The traditional preparation methods of nanomaterials are complex, high cost and time-consuming, and high energy electron beam radiance technology is efficient and convenient and can be treated in large quantities. As a result, more and more attention has been paid to the preparation of nanomaterials. This paper is mainly based on irradiation modification of nanomaterials based on high energy electron beam irradiation technology. Different functionalized nanomaterials have been prepared and applied to the removal domain of environmental pollutants. The main contents of this paper are as follows: 1. contact Diatomite is usually used as a carrier of vanadium catalyst for the synthesis of sulfuric acid by method. The pore size of the natural diatomite is small and the blockage is serious. The mass transfer rate of the reactant in the channel is reduced. In the second chapter of the paper, we irradiate natural diatomite by high energy electron beam irradiation technology to improve the pore size distribution of the diatomite, thus improving the pore size distribution of the diatomite. The quality of diatomite as a catalyst carrier. The results show that the effect of high energy electron beam in the process of irradiation of diatomite, the explosion and thermal effect of Kulun can effectively increase the pore size of diatomite. The diatomite channel after the modification is dredged, so it has a larger aperture, which is beneficial to improve the mass transfer rate of sulfur dioxide and air in the diatomite channel and the contact area between the reactant in the process of sulphuric acid synthesis, thus improving the traditional leaf of the diatomite as the catalyst carrier of the catalyst in the process of sulphuric acid synthesis,.2.. Only a small portion of the fertilizer can be absorbed by plants after fertilization, and most of the fertilizer that is not used will be washed, leaching and evaporating into the water body. In the air and soil, it not only causes the loss of the fertilizer efficiency, but also causes serious environmental pollution. Therefore, the ability to attach to the plant leaves is strong and the utilization rate is high. In the third chapter of the paper, we use high energy electron beam irradiation technique to modify the natural nano material attapulgite soil to improve its dispersibility and specific surface area. Then, the straw ash and the modified attapulgite soil are compounded to a certain mass ratio, and a new type of leaf fertilizer control loss agent is prepared. The results show that the leaf fertilizer control agent has a porous micronano network structure and a larger specific surface area. It can adsorb a large amount of nitrogen fertilizer and immobilate it in its own network structure. In the process of fertilization, the network structure can be blocked by the microstructure on the leaves of plant, so it is not easy to keep on the leaf. Loss, increasing the utilization of foliar fertilizer,.3. iron is essential in the growth and development of plants. If iron deficiency occurs, it will lead to yellow leaf disease and affect the quality and yield of crops. Compared with the root fertilizer, iron foliage fertilizer can quickly supplement two valent iron ions and maintain normal growth and development of plants. The easy loss of fertilizer and the instability of ferrous ions are one of the key problems in reducing the efficiency of iron foliar fertilizer. Therefore, a new type of iron foliar fertilizer is needed to effectively immobilization of ferrous ions, delay its oxidation rate and improve the utilization efficiency of ferrous ions. In the fourth chapter of the paper, we will microcrystalline Cellulose is modified to obtain cellulose with a large number of carboxyl groups on the surface, and the electrostatic interaction between carboxyacid and two valence iron ions can fix two valence iron ions, thus forming a compound of both. It can enhance the adhesion ability of iron on the crop leaves and delay the oxidation rate of ferrous ions. In addition, using the sensitivity of the carboxylic acid roots to pH, the two valence iron ions are dissociated from the hydrogen ions under the acidic condition. Therefore, the release of iron elements can be controlled by adjusting the pH value of the solution, and the utilization efficiency of the foliar fertilizer can be improved. The controlled release iron element leaf fertilizer prepared by this method can meet the demand for iron in different growth period of the crop, promote the UV light of only 2%-5% in the.4. solar light, which leads to the low efficiency of the photocatalyst excited by ultraviolet light, which restricts the application of photocatalyst in the field of pollutant degradation. Therefore, the preparation of the photocatalyst in the field of pollutant degradation is prepared. The fifth chapter of the paper provides a preparation method of Photocatalyst (MnO2/C complex) that can degrade organophosphorus pesticides based on high energy electron beam irradiation technology. The electrons and hydrogen radicals, such as the reductive particles, can reduce the MnO4- and prepare the MnO2 nanoparticles. At the same time, the thermal effect and sputtering effect of the high energy electron beam can make the surface of the graphite oxide more rough. The MnO2 nanoparticles are fixed to the stone by the hydrogen bond formed between the hydroxyl group of the MnO2 surface and the oxygen containing groups on the graphite surface. The experimental results show that the MnO2/C composites prepared by this method have excellent dispersibility and photocatalytic properties. The degradation of glyphosate to non-toxic inorganic small molecule.5. medical waste under the excitation of sunlight can lead to a large number of anti biotic residues in the environment, which leads to the increase of bacterial resistance. In the sixth chapter of the paper, we directly treated the antibiotic residues in medical waste by high energy electron beam irradiation technology, irradiated the antibiotics in situ, and discussed the degradation efficiency of antibiotics by high energy electron beam irradiation dose, initial concentration of anti raw solution, free radical scavenger and The results showed that the degradation efficiency of amoxicillin, ofloxacin and Cefradine was 97.02%, 97.61% and 96.87%. high performance liquid chromatography - mass spectrometry and infrared spectrum analysis showed that amoxicillin, ofloxacin and Cefradine were similar in degradation products after degradation. In addition, the mechanism of the degradation of antibiotics was further discussed in this chapter. It was found that OH played a leading role in the degradation of antibiotics by electron beam irradiation.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X505;TB383.1

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