基于纳米材料的新型硝酸盐电化学传感器研究

	基于纳米材料的新型硝酸盐电化学传感器研究
	逯文晶
学位类型	硕士
导师	潘大为
	2013-05-26
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位专业	海洋化学
关键词	纳米材料化学修饰电极伏安分析法硝酸盐检测
摘要	近年来，由于农作物施肥、工业生产等人类活动使得环境的中硝酸盐的含量超出了环境的承受能力，从而带来了众多环境问题，造成了不同程度的经济损失。环境中不断积累的硝酸盐不断积累，其造成的污染正在进入突发性、连锁性和区域性的爆发阶段，已经得到世界各部门的普遍关注。因此，发展快速准确的硝酸盐检测方法和技术具有重要意义。目前，国际上已经发展了多种硝酸盐的检测方法，但大都存在设备昂贵、操作复杂、分析测试及维护费用高等问题缺点，无法满足硝酸盐快速、实时检测的需求。电化学伏安分析法具有准确、快速、操作简单、便携、可现场分析以及抗样品浑浊、抗颜色干扰等优点，在硝酸盐快速检测分析中具有重要的地位。电极材料的选择是电化学伏安分析法的核心问题，其直接决定分析检测性能。现有的硝酸盐检测电极主要存在电极对硝酸盐电化学还原的传质速率低、过电位高、检测限高等不足。而纳米材料的快速发展为解决上述问题提供了新思路和新方法。本文针对硝酸盐检测分析中存在的诸多问题，构建了三种基于纳米材料的硝酸盐电化学传感器，并进一步应用到硝酸盐的检测分析中。主要研究内容包括以下几个方面：1．碳纳米管/铜氧化物纳米复合材料修饰电极用于硝酸盐的检测。利用二价锡离子作为桥梁，采用自发氧化还原反应制备了一种新颖的碳纳米管/铜氧化物纳米复合材料，并通过多种分析手段对此纳米材料的物理化学性能进行了表征。实验结果表明，通过简单反应制备得到的碳纳米管/铜氧化物纳米复合材料具有很好的电化学活性，对硝酸盐具有很好较突出的电催化还原活性，硝酸盐在此纳米复合材料修饰电极上有更正的还原过电位。2. 铜纳米粒子修饰的金电极用于硝酸盐的检测。为了进一步改进工作电极的电极重现性和稳定性差的缺点，采用电化学沉积技术制备了铜纳米粒子修饰电极。电极的制备过程简单、快速，铜纳米粒子的大小均一，并具有很好较好的电化学活性，并且无需电极活化等预处理，能够满足快速检测分析的需求。通过扫描电子显微镜和电化学方法对电极的性能进行了表征，并详细研究了硝酸盐在电极上的电化学响应行为。实验结果表明：该电极对硝酸盐在10 ~ -1000µM浓度范围内呈良好的线性响应，线性斜率为14.6 nA/µM。电极具有良好的重现性，20次测定的相对标准偏差为2.0%。将其应用于当地实际自来水样品的检测，结果与紫外分光光度法测定的结果相吻合。同时对电极检测硝酸盐的机理进行了研究，硝酸盐峰电流随扫描速率的平方根成正比，表明电极反应受扩散控制。3. 壳聚糖/铜纳米粒子修饰电极用于硝酸盐的检测。为了加快硝酸盐的扩散过程，以期改进工作电极的检测限较高和电极稳定性差的缺点，本实验引入壳聚糖作为修饰物，利用壳聚糖对铜的配位作用以及在酸性溶液中带正电性等优良特性，提高了电极的长期稳定性并降低了检测限。实现结果显示该电极的检测线性范围为1 -~ 1000 µM，线性斜率为31.1 nA/µM，并且电极3天内检测的相对标准偏差为2.0%%。电极可用于实际自来水中硝酸盐的检测分析，与紫外分光光度法测定结果相吻合。该电极具有较高的灵敏度、较好的稳定性，在实时在线检测中具有较大的应用前景。
其他摘要	With the rapid development of industry and agriculture activities, the pollution of nitrate, which goes beyond the carrying capacity of the environment, induces serious damage to both the environment and human health. Nitrates tend to accumulate in environment, and now the nitrate pollution has been entering an outbreak period with suddenness, link system and regionalization. Therefore, nitrate pollution has got great attention of government worldwide and scientists. It has become very necessary to development of rapid and accurate detection of nitrate.To date, various analytical techniques have been developed to determine nitrate in environment samples. However, these common methods are not only cumbersome and expensive, but also require complicated operation and high cost of testing and maintenance, which could not meet the growing demands of the fast and real-time nitrate detection. As an accurate, fast, simple, strong anti-interference, portable, on site analytical technique, voltammetry technique has shown great prospects in repaid detecting trace nitrate. The choice of electrode materials is the key problem to the voltammetry analysis, which directly determined the performance of analytical detection. However, a direct determination of nitrate by using bare electrodes is difficult, mainly attributed to the slow charge-transferring speed, much higher over potential, and higher analytic limitation. Fortunately, the nanomaterials science, which has fast been developing lately, provides new thought and method to solve these problems.Thus, in this paper, three nanomaterial-based novel electrochemical nitrate sensors were proposed, and successfully used in nitrate ions determination. The main contents are as follows:1. The MWCNTs/CuOx nanocomposites was successfully synthesized, and further applied to the detection of nitrate. A novel and facile method was introduced for the preparation of CNTs/CuOx nanocomposites, which is based on in situ spontaneous redox. Various methods have been used to characterize the as-prepared nanocomposites. The results demonstrate that CuOx nanoparticles were well distributed on the surface of MWCNTs. The preliminary application of CNTs/CuOx nanocomposites towards electrochemical determination of nitrate was also investigated, and it shows that the nanocomposites modified electrode has much higher over potential and good electrocatalytic response to nitrate reduction.2. The CuNPs modified electrode was used for voltammetry determination of nitrate. The electrochemistry technology was used for the preparation of CuNPs. The experiment results showed that the CuNPs with uniform size were well distributed on the surface of gold electrode, and it showed excellent electrochemical activity. The electrochemistry method has the advantages of quick and simple process, without electrode activation pretreatment, and can meet the requirements of rapid analysis. It was further applied to study tap water, and the results obtained from this electrode are in accordance well with those detected by ultraviolet spectrophotometry. The electrode has not been degraded after 20 repetitive measurements of nitrate with relative standard deviations of 2.0%. Moreover, Experiment results showed that the peak current is proportional to square root of scan rate, which indicated that the procedure is controlled by diffusion.3. The Chitosan/CuNPs modified electrode was used for voltammetry determination of nitrate. The chitosan, which contain suitable functional groups, such as carboxyl and hydroxyl, was introduced to modified the electrode and can help to hence the long-term stability, since it crosslink with copper ions. Moreover, it was positively charged under acidic conditions that can help to improve the detecting sensitivity. The linear range of the electrode to nitrate determination is 1 ~ 1000µM and the slope of the regression line was 31.1 nA / µM. The relative standard deviation within 3 days of testing was 2.0%, which suggested a great potential capacity for the field, continuous and automatically nitrate monitoring.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/6713
专题	中国科学院烟台海岸带研究所知识产出_学位论文
推荐引用方式 GB/T 7714	逯文晶. 基于纳米材料的新型硝酸盐电化学传感器研究[D]. 北京. 中国科学院研究生院,2013.

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