化学修饰电极检测微污染水中的亚硝酸根和过氧化氢

发布时间：2019-02-12 11:32

【摘要】：在工业迅猛发展、城市化建设加速前进的当今,环境污染问题成为了被人们日渐重视,亟需解决对象之一。其中,水环境与人类生活息息相关,其污染更被越来越多的人重视。亚硝酸根和过氧化氢是两种在微污染水体中比较常见的物质,它们极易溶于水,然而大剂量的摄入都对人体有严重的毒害作用,甚至威胁生命。对此,越来越多的研究学者着眼于研究新型材料对水质进行检测。常见的检测方法主要有光谱法、色谱法、化学发光法和电化学方法等,其中,电化学方法是利用化学修饰电极对水样进行检测,具有操作简单、成本低廉、反应灵敏等优点,被广泛运用。但是,化学修饰电极的稳定性差一直是它的缺点,因此,需要制备具有低检测限、高稳定性的电化学检测电极,用来检测微污染水。本文以FTO为基底,利用两步电沉积法,成功制备了基于Ni、Ag和MWNTs修饰的Ni/Ag/MWNTs/FTO电极,操作简单,且性能稳定。研究表明,该电极对NO2-具有良好的催化氧化能力,通过其对亚硝酸根的安培响应可知,在1 μmol·L-1～0.5 mmol·L-1浓度范围,安培响应与亚硝酸根浓度之间具有较好的线性关系,相关系数r2=0.9932,根据多次实验得到最低检测限为4.6×10-7mol·L-1。该电极具有较高的灵敏度和重现性,且对多种阴阳离子具有较好的抗干扰能力,能应用于实际样品的检测。在Ni/Ag/MWNTs/FTO修饰电极的基础上,进行性能改良,以玻碳电极(GCE)为基底电极,成功制备了Cu、Ag和MWNTs修饰的Cu/Ag/MWNTs/GCE电极,性能稳定,操作方便。该电极对N02-具有更好的催化氧化能力,检测限达到2×10-7 mol·L-1,比Ni/Ag/MWNTs/FTO修饰电极的检测限(4.6×10-7 mol·L-1)低了一半多。利用Cu/Ag/MWNTs/GCE修饰电极对亚硝酸根的安培检测可知,在亚硝酸根浓度为1μmol·L-1 ～0.05 mmol·L-1范围内,电流与亚硝酸根浓度呈现良好的线性关系,具有较高的灵敏度,并且对多种阴阳离子具有抗干扰能力。在研究电极对过氧化氢的检测中,利用分步电沉积法,成功制备出了Sn/AgNWs/MWNTs修饰电极。该电极在0.001 mmol·L-1～0.1 mol·L-1浓度范围内,其电流响应与过氧化氢浓度呈现良好的一次线性关系,r2=0.9960。该电极对过氧化氢具有明显的安培响应,且对低浓度H202具有较灵敏的电流响应值,检测限达到1.05×10-6 mol·L-1,通过考察峰电流与扫速的关系,该电极的反应过程为吸附控制。本次工作还对MWNT改性,利用水热法成功制备出N掺杂的MWNTs,并利用电沉积,制备了N-MWNTs/AgNWs/GCE电极,该电极对过氧化氢具有较好的电化学响应,能在低浓度条件下检测出H202,在1 μmol·L-1 ～0.08 mol·L-1 H2O2浓度范围内,其电化学响应值与H202浓度呈良好的一次线性关系,最低检测限达到2.74×10-7 mol·L-1。该电极对柠檬酸CA、葡萄糖和抗坏血酸等干扰物质具有较好的抵抗能力,过氧化氢的相应电流曲线,能在干扰物质加入后迅速恢复稳定,且稳定性和重现性良好。研究表明,本文制备的几种电极,均具有较低的检测限和较强的稳定性,对多种离子或物质具有抗干扰能力,能应用于实际微污染水样检测。
[Abstract]:With the rapid development of the industry and the acceleration of the construction of the urbanization, the problem of environmental pollution is becoming more and more important, and it is urgent to solve one of the objects. Among them, the water environment is closely related to human life, and its pollution is more and more attention. Nitrite and hydrogen peroxide are two more common substances in micro-polluted water. They are very soluble in water. However, large doses of hydrogen peroxide have serious toxic effects on the human body, and even threaten life. In this regard, more and more researchers have focused on the research of new materials for the detection of water quality. the common detection method mainly has the advantages of spectrum, chromatography, chemiluminescence, electrochemical method and the like, wherein the electrochemical method is used for detecting the water sample by using the chemically modified electrode, and has the advantages of simple operation, low cost, sensitive reaction and the like, and is widely applied. However, the stability difference of the chemically modified electrode has always been a disadvantage, and therefore, it is necessary to prepare an electrochemical detection electrode with a low detection limit and a high stability, for detecting the micro-polluted water. Based on FTO, the Ni/ Ag/ MWNTs/ FTO electrode modified based on Ni, Ag and MWNTs was successfully prepared by two-step electrodeposition, and the operation was simple and the performance was stable. The results show that the electrode has good catalytic oxidation ability to NO2, and it can be found that the concentration range of 1. mu.mol 路 L-1-0.5 mmol 路 L-1, the response of ampere and the concentration of nitrite have a good linear relationship, and the correlation coefficient r2 is 0.9932, The minimum detection limit of 4. 6-10-7mol 路 L-1 was obtained from a number of experiments. The electrode has high sensitivity and reproducibility, and has better anti-interference ability for a plurality of positive and negative ions, and can be applied to the detection of an actual sample. On the basis of Ni/ Ag/ MWNTs/ FTO modified electrode, the properties of Cu, Ag and MWNTs modified Cu/ Ag/ MWNTs/ GCE electrodes were successfully prepared by using glass-carbon electrode (GCE) as the base electrode. The electrode pair N02-has better catalytic oxidation capacity, the detection limit reaches 2-10-7 mol 路 L-1, and the detection limit of the electrode is less than that of the Ni/ Ag/ MWNTs/ FTO modified electrode (4. 6-10-7 mol 路 L-1). It is found that the concentration of nitrite in the range of 1. m u.mol. L-1 to 0.05 mmol 路 L-1 shows a good linear relationship with the concentration of nitrite in the range of 1. m u.mol. L-1 to 0. 05 mmol 路 L-1 by the Cu/ Ag/ MWNTs/ GCE modified electrode. Sn/ AgNWs/ MWNTs modified electrode was successfully prepared by the step-by-step electrodeposition method in the detection of hydrogen peroxide by the study electrode. The current response of the electrode in the range of 0.001 mmol 路 L -1 to 0.1 mol 路 L-1 shows a good linear relationship with the concentration of hydrogen peroxide, r2 = 0.9960. The electrode has an obvious ampere response to the hydrogen peroxide, and the low-concentration H202 has a sensitive current response value, the detection limit reaches 1. 05-10-6 mol 路 L-1, and the reaction process of the electrode is adsorption control by examining the relation between the peak current and the scanning speed. In this work, the MWNT was modified and the N-doped MWNTs was successfully prepared by the hydrothermal method, and the N-MWNTs/ AgNTs/ GCE electrode was prepared by electrodeposition. The electrode has a good electrochemical response to the hydrogen peroxide, and the H202 can be detected under the low concentration condition, and the H202 is in the range of 1umol 路 L-1-0.08mol 路 L-1H2O2. The electrochemical response has a good linear relationship with the H202 concentration, and the minimum detection limit is from 2.74 to 10-7 mol 路 L-1. The electrode has good resistance to the interfering substances such as the citric acid CA, the glucose and the ascorbic acid, and the corresponding current curve of the hydrogen peroxide can be quickly recovered and stable after the interfering substances are added, and the stability and the reproducibility are good. The research shows that several kinds of electrodes prepared in this paper have lower detection limit and strong stability, and have anti-interference ability to various ions or substances, and can be applied to the detection of actual micro-polluted water samples.
【学位授予单位】：浙江工商大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O657.1;X832

【参考文献】