基于紫外吸收光谱法的水中氨氮浓度测量方法研究  

Research on measurement method of ammonia nitrogen concentration in water based on ultraviolet absorption spectrum

作　　者：蔡树向 孙冰 冯巍巍 徐东升 CAI Shuxiang;SUN Bing;FENG Weiwei;XU Dongsheng(School of Electromechanical and Automotive Engineering,Yantai University,Yantai,Shandong 264005,China;CAS Key laboratory of Coastal Environmental Processes and Ecological Remediation,Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences,Yantai,Shandong 264003,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao,Shandong 266071,China;University of the Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]烟台大学机电与汽车工程学院,山东烟台264005 [2]中国科学院海岸带环境过程与生态修复重点实验室(烟台海岸带研究所),山东烟台264003 [3]中国科学院海洋科学研究中心,山东青岛266071 [4]中国科学院大学,北京100049

出　　处：《光电子．激光》2021年第8期888-893,共6页Journal of Optoelectronics·Laser

摘　　要：氨氮是水中常见的污染物,是各类水质检测重要的指标。水中氨氮含量超标会影响水生植物、动物的生长,导致水体环境恶化,水环境受到污染。因此,加强水中氨氮的监测尤为重要。本文基于紫外光谱检测技术,搭建了水中氨氮浓度紫外光谱检测系统。通过检测系统将液相氨氮转换为气相氨气,获得氨气在190-235 nm波长间的紫外吸光度,并分别采用傅里叶滤波和傅里叶变换两种数据处理方式对吸光度信号进行分析。结果表明,经傅里叶滤波后氨气的吸光度在190-235 nm波长间存在明显的周期性的峰值,周期约为4 nm,随着氨气浓度的增加其吸光度峰值也增大。通过最小二乘法拟合发现,氨气的吸光度和浓度之间存在着良好的线性关系,相关系数为0.99814。经傅里叶变换后的吸光度信号在频域中存在特征频率,通过拟合发现,振幅强度与氨氮浓度之间同样存在线性关系,相关系数为0.98686。实验证明可以根据氨气吸光度获得氨氮的浓度,为水中氨氮浓度的检测提供了新的检测手段。Ammonia nitrogen is a common pollutant in water, and it is an important indicator of various water quality detection.Excessive ammonia nitrogen content in water will affect the growth of aquatic plants and animals, which will lead to water environment deterioration and water environment pollution.Therefore, it is very important to strengthen the monitoring of ammonia nitrogen in water.In this paper, based on the UV spectrum detection technology, the UV spectrum detection system of ammonia nitrogen concentration in water was built.Through the detection system, ammonia nitrogen in liquid phase is converted into gas phase ammonia, and the ultraviolet absorbance of ammonia gas in the wavelength range of 190-235 nm is obtained, and the absorbance signal is analyzed by Fourier filtering method and Fourier transform.The results show that after Fourier filtering, the absorbance of ammonia has obvious periodic peaks in the wavelength range of 190-235 nm, and the period is about 4 nm.With the increase of ammonia concentration, the absorbance peak also increases.It was found that there was a good linear relationship between the absorbance and concentration of ammonia by least square method, and the correlation coefficient was 0.998 14.After Fourier transform, the absorbance signal has characteristic frequency in frequency domain.Through fitting, it is found that there is also a linear relationship between amplitude intensity and ammonia nitrogen concentration, and the correlation coefficient is 0.986 86.The experimental results show that the concentration of ammonia nitrogen can be obtained according to the absorbance of ammonia, which provides a new detection method for the concentration of ammonia nitrogen in water.

关 键 词：紫外光谱 傅里叶变换 特征频率 吸光度 氨氮 

分 类 号：O439[机械工程—光学工程]