低温等离子体氧化—碳纳米管吸附集成技术去除水中扑热息痛行为与机理

发布时间：2018-04-02 00:02

本文选题：低温等离子体　切入点：碳纳米管　出处：《南京大学》2017年硕士论文

【摘要】：扑热息痛又名对对乙酰氨基酚,是一种常见的解热镇痛类药物,也是合成许多药品的必要成分,是我国原料药产量最大的药物品种之一。随着药品/个人护理用品的大量使用,以及医药废水的排放,地表水中已经检测出扑热息痛。环境中的扑热息痛会对生物体造成遗传毒性、肝毒性、内分泌干扰等负效应。因此,研究扑热息痛的高效去除方法对保障水质安全具有重要的意义。传统去除扑热息痛的方法主要有传统颗粒/粉末活性炭吸附法、氧化法(O3、H202,NaClO)等。近些年,碳纳米管的发现为人们提供了新型一维纳米材料并成为吸附与催化领域的研究热点,有学者尝试利用碳纳米管对扑热息痛的高富集效应,开展水中痕量扑热息痛的检测与分析。此外,低温等离子体氧化技术的发展也为难降解有机物污染物的降解提供了更加高效的途径。因此,利用碳纳米管吸附水中有机污染物,并与低温等离子体氧化联用,不仅通过吸附、氧化协同去除水中有机污染物的,还可实现碳纳米管的同步再生。基于上述研究背景和技术思路,论文以模拟废水中扑热息痛的为目标污染物,研究比较碳纳米管吸附、低温等离子体氧化、碳纳米管吸附-低温等离子体氧化对扑热息痛的去除行为与机理,研究表明:1)低温等离子体可以氧化降解扑热息痛,其降解机理为在高压高频电源放电过程中,通入的空气会被大量电离,并形成大量高能电子和.OH、.O、HO2.等自由基,将扑热息痛降解为小分子有机物。溶液初始浓度、输出功率、气体流速、pH对扑热息痛降解率有显著影响。2)碳纳米管可以吸附模拟废水中扑热息痛,其平衡吸附容量为85.1mg/g,附等温线符合Langmuir吸附等温方程,主要为单层吸附,其吸附动力学过程符合准二级吸附动力学模型,颗粒内扩散是限制吸附速率的主导因素。3)吸附、低温等离子体、吸附-等离子体联用对扑热息痛的去除率分别为70%、82.1%、98%。吸附-等离子体联用对扑热息痛的去除率明显高于单一吸附和单一低温等离子体氧化。这主要归因为碳纳米管吸附与等离子体氧化协同效应:1)碳纳米管吸附富集低浓度扑热息痛的同时可以提高低温等离子体的氧化降解效率,且碳纳米管表面基团也起到了催化作用;2)低温等离子体在氧化降解扑热息痛的同时对吸附饱和的碳纳米管进行了原位再生,从而保证碳纳米管始终具有吸附能力。
[Abstract]:Paracetamol, also known as paracetamol, is a common antipyretic and analgesic drug, and also a necessary component in the synthesis of many drugs. Paracetamol has been detected in surface water. Environmental paracetamol can cause genotoxicity, hepatotoxicity, endocrine disruptions and other negative effects on organisms. It is of great significance to study the efficient removal methods of paracetamol to ensure the safety of water quality. The traditional methods of removing paracetamol include traditional particle / powder activated carbon adsorption method, oxidation method and so on. The discovery of carbon nanotubes (CNTs) provides a new type of one-dimensional nano-materials and has become a hot research topic in the field of adsorption and catalysis. Some scholars have tried to utilize the high enrichment effect of carbon-nanotubes on paracetamol. Detection and analysis of trace acetaminophen in water. In addition, the development of low temperature plasma oxidation technology also provides a more efficient way to degrade organic pollutants. Therefore, carbon nanotubes are used to adsorb organic pollutants in water. In combination with low temperature plasma oxidation, the simultaneous regeneration of carbon nanotubes can be realized not only by adsorption and oxidation, but also by simultaneous regeneration of carbon nanotubes. The removal behavior and mechanism of paracetamol by carbon nanotube adsorption, low temperature plasma oxidation, carbon nanotube adsorption and low temperature plasma oxidation were studied. The results show that low temperature plasma can oxidize and degrade paracetamol, and its degradation mechanism is that during the discharge of high voltage high frequency power supply, the incoming air will be heavily ionized, and a large number of high energy electrons and free radicals, such as. Acetaminophen was degraded into small molecular organics. The initial concentration of the solution, output power, gas flow rate and pH have significant effects on the degradation rate of paracetamol. 2) carbon nanotubes can adsorb paracetamol in simulated wastewater. The equilibrium adsorption capacity is 85.1 mg / g, and the isotherm accords with the Langmuir isotherm equation, which is mainly monolayer adsorption. The adsorption kinetic process accords with the quasi-second-order adsorption kinetic model, and the intraparticle diffusion is the dominant factor to limit the adsorption rate. Low temperature plasma, The removal rates of paracetamol by adsorption-plasma combination were 70 and 82.1%, respectively. The removal rate of paracetamol by adsorption-plasma combination was significantly higher than that of single adsorption and single low temperature plasma oxidation, which was mainly attributed to carbon nanotubes. The synergistic effect of adsorption and plasma oxidation: (1) carbon nanotubes adsorb and enrich paracetamol at low concentration and at the same time improve the oxidation degradation efficiency of low temperature plasma. The surface group of carbon nanotubes also plays a catalytic role. The low temperature plasma regenerates the adsorbed saturated carbon nanotubes in situ while oxidizing and degrading paracetamol so as to ensure the adsorption ability of carbon nanotubes.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;X52

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