紫外—可见光谱水质检测多参数测量系统的关键技术研究

发布时间：2019-07-04 13:35

【摘要】：水是生命之源，人类在生活和生产活动中都离不开水。然而，随着我国经济的高速发展和城市化进程的加快，暴露的水环境污染问题也日趋严重，水质或水体污染事件频发，凸显了我国水环境形势不容乐观。水质的优劣不仅与工农业生产安全和人类健康密切相关，而且还依赖于水质检测技术做保障，以此评判、预测和监测水质的优劣。诚然，传统的仪器检测设备可以对水质参数进行检测，但一般只对单一参数进行测量。例如，水质COD、TOC、TURB和NO3-N等参数的检测，其通常需要COD分析仪，TOC分析仪，浊度计，NO3-N分析仪等设备进行单独测量，这不仅不利于数据的整合，而且还增加了检测成本。近年来，作为光谱分析的水质检测技术之一的紫外-可见光吸收光谱法，它不仅摒弃了化学分析和电化学分析及色谱分析等水质检测技术水样预处理繁杂、测量周期长、所需化学试剂多的缺点，而且还具有检测速度快、成本低和可实现在线、原位测量等优点，日渐为世人所瞩目。然而，目前的紫外-可见光吸收光谱法，一般为单一参数在线检测，国内尚不能实现水质COD、TOC、TURB、NO3-N的多参数同时在线检测。本文在四川省科技支撑计划项目“多功能水质实时自动监测技术开发与产品研制”（项目编号：2012SZ0111）和四川碧朗科技有限公司横向合作科研项目“光谱多参数水质在线自动监测仪研制”（合同编号：1042012920140453）及国家自然科学基金项目“SFL-Contourlet的构造及其特性研究”（批准号：61201346）的联合资助下，开展了紫外-可见光谱水质多参数检测的理论、仪器、方法技术及应用研究工作，研制了一套涵盖水质光谱数据采集、水质光谱处理、水质参数解算，到实验室分析验证，再到实际水质多参数检测完整流程的水质多参数检测仪器系统，且系统已具有完全自主知识产权。论文的研究内容，主要包括： ①阐述了光谱法或光谱技术水质参数检测的国内外研究现状及发展趋势，通过对国内外现有水质检测技术进行详尽对比分析的基础上，本文提出了紫外-可见光谱法水质多参数检测的原理和方法技术及应用，基此，系统、深入开展了紫外-可见光谱法水质多参数检测的水质光谱处理、水质参数解算等的关键技术问题研究。 ②研制了紫外-可见光谱法水质多参数检测的仪器系统。通过对紫外-可见光谱法水质检测的原理进行详细分析，研究了水质多参数的检测原理，分析了多参数光谱检测的可行性。在此基础上，构建了水质多参数检测仪器系统的实现方案，设计、仿真、加工制作和测试了浸入式光程差分水质检测探头。该探头在进行水质光谱数据采集时，能有效地降低噪声干扰，提高系统灵敏度，并能快速、准确找出待测水体的敏感波长范围。通过采用以微型光纤光谱仪为核心的光谱测量单元，结合紫外-可见吸收光谱分析法，完成水样的COD、TOC、TURB和NO3-N多参数检测。同时，基于LabVIEW开发平台，进行系统软件设计并进行调试，实现了对流路、清洗、处理、显示、存储、打印及主控系统的仪器功能，此为光谱法水质多参数检测的实现提供了硬、软件条件或平台。 ③研究了基于小波包去噪的水质光谱处理方法和多元散射校正的水质光谱处理技术方法。针对地表水、城市生活污水中主要污染物在线检测与控制的需求，以紫外-可见光谱法水质COD、TOC、TURB和NO3-N多参数检测为具体研究对象，在分析水质光谱信息特征的基础上，提出了基于小波包去噪的水质光谱处理方法，借以提高水质光谱的信噪比。研究结果表明，水样的原始紫外-可见吸收光谱经小波包去噪处理后，噪声得到了明显抑制，且特征得到了较好的保留。针对水中悬浮物对光谱的散射会对水样的紫外-可见吸收光谱产生基线漂移、平移等，此将严重影响系统的稳定性和检测精度问题，进而将直接影响光谱法对水质COD的检测。为此，研究了一种基于多元散射校正的水质光谱处理方法。通过多元散射校正方法，可在不影响水样紫外-可见吸收光谱特征的前提下，能够对水中悬浮物引起散射干扰或水质浊度引起基线偏移的吸收光谱曲线进行有效的校正。这不仅提高了光谱法检测水质COD的信噪比，而且还对化学计量法建立准确有效的水质检测COD分析模型进行了有效的数据预处理。 ④研究了主元分析进行水质光谱降维和最小二乘支持向量机对水质参数软测量建模的水质光谱处理方法技术。由于水质紫外-可见光谱通过小波包去噪和多元散射校正后，依然存在水质光谱采集的冗余及多重共线问题，应用主元分析方法对水质光谱信号进行降维处理，再应用最小二乘支持向量机对水质参数COD进行软测量建模。研究结果表明，经主元分析方法降维处理后的水质光谱数据，去除了冗余信息，保留了有效特征，在此基础上，应用最小二乘支持向量机进行水质参数的软测量建模，可以提高系统的建模精度和水质COD参数的解算精度。 ⑤开展了紫外-可见光谱法水质多参数检测仪器样机的性能测试研究工作。为了确保紫外-可见光谱法水质多参数检测仪器系统的有效、稳定运行，需要依据相关标准，对研制的仪器样机的性能进行测试。测试结果表明，仪器样机对COD即化学需氧量标液的测试精度小于4.70%，重复性小于1.43%；对TOC即总有机碳的测试精度小于2.69%，重复性小于1.98%；对TURB即浊度的测试精度小于4.78%，重复性小于1.55%；对NO3-N即硝酸盐氮的测试精度小于4.67%，重复性小于2.92%。可见，研制的仪器样机性能指标，不仅达到了立项研究项目《任务书》的设计要求，而且由中国测试技术研究院化学研究所出具的测试报告证明，性能指标满足我国及行业的有关标准规范。本文将光谱学、光电技术、环境科学、化学计量方法、信号分析与处理等学科专业知识进行了有机结合，率先在国内研究并构建了基于紫外-可见光谱法水质多参数检测仪器系统。论文研究成果——研制的仪器样机，，已通过了四川省科技厅组织专家的成果鉴定，这对进一步开展紫外-可见光谱水质多参数检测的理论、仪器、方法技术及应用研究工作，具有重要的理论和现实意义。
文内图片：

图片说明：013年十大流域水质状况
[Abstract]:Water is the source of life, and human is inseparable from water in life and production activities. However, with the rapid development of China's economy and the acceleration of the process of urbanization, the environmental pollution of the exposed water is becoming more and more serious. The quality of water is not only closely related to the safety of industrial and agricultural production and human health, but also on the quality detection technology to judge, predict and monitor the quality of water. It is true that conventional instrument detection equipment can detect water quality parameters, but generally only a single parameter is measured Quantity. For example, the detection of parameters such as COD, TOC, TURB and NO3-N of water quality, which usually requires separate measurement of equipment such as COD analyzer, TOC analyzer, turbidity meter, and NO3-N analyzer, is not only detrimental to the integration of the data, but also increases the detection. In recent years, the ultraviolet-visible-light absorption spectrum method, which is one of the water quality detection techniques for spectral analysis, has not only discarded the water samples such as chemical analysis and electrochemical analysis and chromatographic analysis, but also has the advantages of complex pretreatment, long measurement period and many chemical reagents needed. the invention also has the advantages of high detection speed, low cost and can realize on-line and in-situ measurement and the like, However, the present ultraviolet-visible-light absorption spectrum method is generally used for on-line detection of single parameter, and the multi-parameter simultaneous on-line inspection of water quality COD, TOC, TURB and NO3-N cannot be achieved in China Test. In the "Development and product development of multi-functional water quality real-time automatic monitoring technology" of Sichuan Science and Technology Support Project (Project No.:2012 SZ0111) and the "Development of on-line automatic monitor for spectral multi-parameter water quality" (Contract No.:1042012920140453) of the horizontal cooperation scientific research project of Sichuan Biang Technology Co., Ltd. and the "Study on the Structure and Characteristics of SFL-Contourlet" of the National Natural Science Foundation of China (Approval No.:61201346) The theory, apparatus, method and application of the multi-parameter detection of UV-visible spectral water quality are carried out with the aid of the aid of the financial support, and a set of data collection, water quality spectrum treatment and water quality parameter calculation covering water quality spectrum data acquisition, water quality spectrum treatment and water quality parameter calculation are developed. The system of multi-parameter detection of the water quality of the complete flow is detected by the multi-parameter detection of the actual water quality, and the system has the full self-knowledge. Know the property right. The research content of the paper, the main In order to include: the present situation and the development trend of the domestic and foreign research on the detection of water quality parameters of the spectrum or the spectral technique are set forth, and the score of the existing water quality detection technology at home and abroad is analyzed in detail. On the basis of the analysis, this paper puts forward the principle and method of the multi-parameter detection of water quality of ultraviolet-visible spectrum, and the key techniques such as water quality spectrum treatment, water quality parameter calculation and so on are carried out in this paper. The study of the problem of operation has developed the multi-parameter of the water quality of the ultraviolet-visible spectrum. The principle of multi-parameter detection of water quality is studied by analyzing the principle of water quality detection of ultraviolet-visible spectrum, and the multi-parameter light is analyzed. On the basis of this, the realization plan, design, simulation and processing of the water quality multi-parameter detection instrument system are constructed, and the immersion type optical path difference is designed, simulated, processed and tested. the water quality detection probe can effectively reduce the noise interference, improve the system sensitivity, and can quickly and accurately find the water body to be detected when the water quality spectrum data acquisition is carried out, And the COD, TOC, TURB and NO3 of the water sample are finished by adopting a spectral measurement unit which is a core of the micro-optical fiber spectrometer and combining the ultraviolet-visible absorption spectrum analysis method. and based on the LabVIEW development platform, the system software is designed and debugged, and the instrument functions of the convection circuit, the cleaning, the processing, the display, the storage, the printing and the main control system are realized, The water quality spectrum processing method based on wavelet packet de-noising and the water of multi-element scattering correction are studied in this paper. According to the requirement of on-line detection and control of main pollutants in surface water and urban domestic sewage, the water quality COD, TOC, TURB and NO3-N multi-parameter of the ultraviolet-visible spectrum are detected as specific research objects, and the water quality light is analyzed On the basis of the characteristic of spectral information, a method of water quality spectrum processing based on wavelet packet de-noising is proposed, The signal-to-noise ratio of the high water-quality spectrum is obtained. The results show that the original UV-visible absorption spectrum of the water sample is obviously inhibited by the wavelet packet de-noising process, and the signal-to-noise ratio of the high-water-quality spectrum is very low. A good retention is obtained. In view of the scattering of the suspended matter on the spectrum, the base line drift, translation, etc. can be caused to the ultraviolet-visible absorption spectrum of the water sample, which will seriously affect the stability and the detection accuracy of the system, and then the direct influence spectroscopy will be obtained. In this paper, a kind of multi-element scattering correction is studied in this paper. By means of a multi-element scattering correction method, the absorption spectrum of the baseline offset caused by scattering interference or water quality turbidity can be caused to the suspended matter in water under the premise of not affecting the characteristics of the ultraviolet-visible absorption spectrum of the water sample. The method not only improves the signal-to-noise ratio of the COD of the water quality detected by the spectrum, but also establishes an accurate and effective water quality detection COD analysis model for the chemical measurement method. In this paper, effective data pre-processing is presented in this paper. The model of water quality parameter soft measurement by the least square support vector machine for water quality spectrum reduction by the principal component analysis is studied. Because the ultraviolet-visible spectrum of the water quality is corrected by the wavelet packet de-noising and the multi-element scattering, the redundant and multiple co-linear problems of the water quality spectrum acquisition still exist, and the main element analysis method is applied to water, carrying out dimension reduction processing on the quality spectrum signal, and then applying the least square support vector machine to the water quality parameter; In this paper, the soft measurement and modeling of the number of COD are carried out. The results show that the data of the water quality is reduced by the principal component analysis method, the redundant information is removed, and the effective characteristics are reserved. On the basis of this, the least-squares support vector machine is applied. Soft measurement and modeling of water quality parameters can improve the modeling precision and water quality of the system The solution precision of the parameters of the quality of the COD is determined. The multi-parameter detection of the water quality of the ultraviolet-visible spectrum is carried out. In order to ensure the effective and stable operation of the instrument system of the multi-parameter detection of the water quality of the ultraviolet-visible spectrum, it is necessary to study the performance of the instrument prototype according to the relevant standards. The test results show that the test precision of the instrument prototype is less than 4.70% and the repeatability is less than 1.43%. The test precision of TOC, which is the total organic carbon, is less than 2.69%, the repeatability is less than 1.98%, and the test precision for TURB is less than 4.7. 8%, the repeatability is less than 1.55%; the test precision for NO3-N, i.e. nitrate nitrogen, is less than 4.6 7%, the repeatability is less than 2.92%. It can be seen that the performance index of the developed instrument prototype not only meets the design requirements of the project for project initiation and research, but also the test report issued by the Institute of Chemical Research of the China Institute of Testing and Technology has proved that the performance index is full In this paper, we combine the professional knowledge of spectroscopy, electro-optical technology, environmental science, chemical measurement method, signal analysis and treatment, and take the lead in the research and construction of ultraviolet-can in China. The instrument system of multi-parameter detection of water quality is presented in this paper. The research results of the instrument and the prototype of the instrument have passed the fruit identification of the experts of the scientific and technological department of Sichuan province, and the theory, the instrument, the method and the application of the multi-parameter detection of the ultraviolet-visible spectrum water quality have been further carried out.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：O433

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