修饰碳纳米管电极电催化降解水中头孢他啶的研究
发布时间：2019-05-06 07:33
【摘要】：近年来,PPCPs的生产和消费越来越多,大量PPCPs排入水环境中,严重影响人类的健康与安全。因此需要对此类污染物进行处理。本文采用电化学催化来降解水中的头孢他啶,主要研究内容如下：1.用5mol·L-1的HNO3对碳纳米管进行纯化,制备碳纳米管电极,选用稀土元素Ce,通过电沉积的方法对碳纳米管电极进行修饰。通过SEM、FTIR、XRD、XPS、塔菲尔曲线、循环伏安等对纯化前后和修饰前后电极进行分析测试,发现修饰后铈以CeO2形态存在,较未修饰电极有更强的催化活性。2.以修饰后的CeO2/MWCNT电极电解头孢他啶溶液,考察电流密度、极间距、pH、支持电解质浓度、初始浓度对去除率的影响,并对比未修饰电极的去除率。发现在电流密度为3.0mA·cm-2、极间距为1cm、pH为6、支持电解质浓度为1.0g·L-1、初始浓度为1mol·L-1的条件下电解1h后,CeO2/MWCNT电极降解头孢他啶的效率几乎高达100%,而未修饰电极则只有34.6%。通过LC-MS分析其可能的降解路径,断裂氨基和羧基,进而断裂碳碳键和碳氮键,然后生成酰胺类物质,转化为有机酸和酮,最终被氧化为水和二氧化碳。3.考察了两电极在不同影响因素下的电流效率,发现在前5min(?)(?)取得较高的电流效率,之后下降很快。CeO2/MWCNT电极的电流效率均大于未修饰电极。4.对两电极在不同影响因素下的动力学模型进行研究,得到在电流密度、极间距、pH、支持电解质浓度变化时未修饰电极降解头孢他啶为零级反应,CeO2/MWCNT电极为二级反应。改变头孢他啶初始浓度,发现未修饰电极仍然符合零级反应特征,而CeO2/MWCNT电极表现出一级反应的特征。
[Abstract]:In recent years, PPCPs production and consumption more and more, a large number of PPCPs discharged into the water environment, seriously affect human health and safety. Therefore, such pollutants need to be treated. In this paper, electrochemical catalysis was used to degrade ceftazidime in water. The main contents are as follows: 1. Carbon nanotubes (CNTs) were purified by HNO3 of 5mol 路L-1 to prepare CNTs electrode. Rare earth element Ce, was used to modify CNTs electrode by electrodeposition. SEM,FTIR,XRD,XPS, Tafer curve, cyclic voltammetry and so on were used to analyze and test the electrode before and after purification and modification. It was found that the modified cerium existed in the form of CeO2 and had stronger catalytic activity than the unmodified electrode. The effects of current density, electrode spacing, pH, supporting electrolyte concentration and initial concentration on the removal rate of ceftazidime solution were studied with modified CeO2/MWCNT electrode, and the removal rate of unmodified electrode was compared. It was found that when the current density was 1cm, pH was 6, the concentration of supporting electrolyte was 1.0g 路L-1 and the initial concentration was 1mol 路L-1, the electrode spacing of 3.0mA cm-2, was 1cm, pH was 6, and the concentration of supporting electrolyte was 1.0g 路L-1. The degradation efficiency of CeO2/MWCNT electrode for ceftazidime was almost 100%, while that of unmodified electrode was only 34.6%. The possible degradation pathway is analyzed by LC-MS, which breaks the amino and carboxyl groups, then breaks the carbon-carbon bonds and carbon-nitrogen bonds, and then forms amides, which are converted into organic acids and ketones, and are eventually oxidized to water and carbon dioxide. 3. The current efficiency of the two electrodes under different influence factors is investigated. It is found that the current efficiency of the two electrodes in the pre-5min (?) The current efficiency of the CEO _ 2 / MWCNT electrode is higher than that of the unmodified electrode, and the current efficiency of CEO _ 2 / CEO _ 2 electrode is much higher than that of the unmodified electrode. The kinetic model of the two electrodes under different influence factors was studied. It was found that the degradation of ceftazidime by the unmodified electrode was a zero-order reaction and the CeO2/MWCNT electrode was a second-order reaction when the current density, the electrode spacing and the electrolyte concentration of pH, were changed. When the initial concentration of ceftazidime was changed, it was found that the unmodified electrode still accorded with the zero-order reaction, while the CeO2/MWCNT electrode showed the first-order reaction.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
本文编号：2469994
[Abstract]:In recent years, PPCPs production and consumption more and more, a large number of PPCPs discharged into the water environment, seriously affect human health and safety. Therefore, such pollutants need to be treated. In this paper, electrochemical catalysis was used to degrade ceftazidime in water. The main contents are as follows: 1. Carbon nanotubes (CNTs) were purified by HNO3 of 5mol 路L-1 to prepare CNTs electrode. Rare earth element Ce, was used to modify CNTs electrode by electrodeposition. SEM,FTIR,XRD,XPS, Tafer curve, cyclic voltammetry and so on were used to analyze and test the electrode before and after purification and modification. It was found that the modified cerium existed in the form of CeO2 and had stronger catalytic activity than the unmodified electrode. The effects of current density, electrode spacing, pH, supporting electrolyte concentration and initial concentration on the removal rate of ceftazidime solution were studied with modified CeO2/MWCNT electrode, and the removal rate of unmodified electrode was compared. It was found that when the current density was 1cm, pH was 6, the concentration of supporting electrolyte was 1.0g 路L-1 and the initial concentration was 1mol 路L-1, the electrode spacing of 3.0mA cm-2, was 1cm, pH was 6, and the concentration of supporting electrolyte was 1.0g 路L-1. The degradation efficiency of CeO2/MWCNT electrode for ceftazidime was almost 100%, while that of unmodified electrode was only 34.6%. The possible degradation pathway is analyzed by LC-MS, which breaks the amino and carboxyl groups, then breaks the carbon-carbon bonds and carbon-nitrogen bonds, and then forms amides, which are converted into organic acids and ketones, and are eventually oxidized to water and carbon dioxide. 3. The current efficiency of the two electrodes under different influence factors is investigated. It is found that the current efficiency of the two electrodes in the pre-5min (?) The current efficiency of the CEO _ 2 / MWCNT electrode is higher than that of the unmodified electrode, and the current efficiency of CEO _ 2 / CEO _ 2 electrode is much higher than that of the unmodified electrode. The kinetic model of the two electrodes under different influence factors was studied. It was found that the degradation of ceftazidime by the unmodified electrode was a zero-order reaction and the CeO2/MWCNT electrode was a second-order reaction when the current density, the electrode spacing and the electrolyte concentration of pH, were changed. When the initial concentration of ceftazidime was changed, it was found that the unmodified electrode still accorded with the zero-order reaction, while the CeO2/MWCNT electrode showed the first-order reaction.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
【参考文献】
相关期刊论文 前1条
1 宋存义;汪翠萍;李晖;;污水处理中几种去除药物及个人护理用品方法的机理及效果比较[J];环境工程学报;2009年11期
，本文编号：2469994
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