基于超声氧化的总氮紫外光谱检测

发布时间：2018-02-28 17:11

本文关键词： 紫外吸收光谱超声氧化偏最小二乘回归算法总氮　出处：《燕山大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着人类社会发展进程的日渐加快,排入海洋、河流、湖泊等水体中的生产废水和生活污水逐渐增多,水体富营养化的程度不断加重,而总氮含量是影响水体富营养化程度的主要因素。为了加强对污染源的总氮的排放控制,需要对水体进行总氮含量的检测。传统的总氮检测方法需要添加化学试剂,容易造成二次污染,且操作繁琐,因此建立绿色环保、高效方便的总氮检测系统具有重要的现实意义和广阔的应用前景。本文分别从氧化消解、干扰物质和模型选择等方面进行研究,建立了水体中总氮的检测系统和数据分析模型。主要研究内容如下:首先,主要介绍了紫外吸收光谱理论、化学计量学中的常用算法和超声空化理论,阐述了多元回归算法和偏最小二乘回归算法的基本原理。其次,研究了海水中在紫外波段有吸收的主要物质的光谱特征。根据海水中主要成分,实验研究了海水中其他物质成分对含氮物质紫外吸收光谱的影响,确定紫外吸收光谱法检测海水中总氮的主要干扰物质是氯离子和溴离子。同时,在紫外波段对硝酸盐和亚硝酸盐进行线性有效吸收范围研究。再次,设计建立了基于超声波氧化的紫外吸收光谱系统,通过分析影响超声空化的因素,确定了超声空化的最佳频率范围,实验研究了氨氮溶液超声空化的最佳反应时间,并对总氮溶液进行了超声氧化消解。最后,确立了紫外吸收光谱最佳建模方法。通过在高纯蒸馏水中加入不同浓度组合的四种物质,构建校正集样本,分别用多元线性回归算法和偏最小二乘回归算法建立校正模型,并进行结果比较,最终确立偏最小二乘回归算法为测量的最佳建模方法。
[Abstract]:With the rapid development of human society, the production wastewater and domestic sewage discharged into the sea, rivers, lakes and other water bodies are gradually increasing, and the degree of eutrophication of water bodies is becoming more and more serious. The total nitrogen content is the main factor that affects the eutrophication degree of water body. In order to strengthen the control of the total nitrogen discharge of the pollution source, the total nitrogen content of the water body needs to be detected. It is easy to cause secondary pollution, and the operation is cumbersome. Therefore, it is of great practical significance and broad application prospect to establish a green, efficient and convenient total nitrogen detection system. The system and data analysis model of total nitrogen in water are established. The main contents are as follows: firstly, the theory of ultraviolet absorption spectrum is introduced. The basic principles of multivariate regression algorithm and partial least square regression algorithm are expounded in this paper, which are commonly used in chemometrics and ultrasonic cavitation theory. The spectral characteristics of the main substances absorbed in the ultraviolet band in seawater were studied. According to the main components in seawater, the effects of other substances in seawater on the UV absorption spectra of nitrogen-containing substances were studied experimentally. It is determined that the main interfering substances for the determination of total nitrogen in seawater by ultraviolet absorption spectrometry are chloride ion and bromine ion. At the same time, the linear effective absorption range of nitrate and nitrite is studied in the ultraviolet band. The UV absorption spectrum system based on ultrasonic oxidation was designed and established. The optimum frequency range of ultrasonic cavitation was determined by analyzing the factors affecting ultrasonic cavitation. The optimum reaction time of ultrasonic cavitation in ammonia nitrogen solution was studied experimentally. Finally, the best modeling method of UV absorption spectrum was established. By adding four kinds of substances with different concentrations in high purity distilled water, the calibration set samples were constructed. The calibration model is established by multivariate linear regression algorithm and partial least square regression algorithm, and the results are compared. Finally, the partial least squares regression algorithm is established as the best modeling method for measurement.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X832;TN23

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