Study On Online Monitoring Technology Of Heavy Metals In Wide Spectrometry Water Quality

Clean water resources are the premise of ecological sustainable development.With the development of industrialization,urbanization and modernization,heavy metals have become the main pollutants of water environment.Heavy metal pollution has become increasingly prominent and has been paid attention to.‘The 14 th five-year plan for ecological environment monitoring’ proposes to strengthen the construction of ecological environment supervision system and supervision capacity,and improve the ability of environmental monitoring and early warning and water pollution traceability.Therefore,it is of great significance to study the wide spectrometry on-line monitoring technology of heavy metals in water quality and realize the long-term high-frequency monitoring of wide area grid of water environment.In view of the deepening needs of water environment treatment in China,it is difficult to meet the on-line monitoring technology of water environment,The research methods,latest trends and current technical problems of heavy metal detection in water quality at home and abroad are fully studied and analyzed in this paper.Taking hexavalent chromium ion and lead ion as the research object,this paper analyzes the current detection methods of heavy metal ions in water quality;For the current water environment,it is difficult to realize high-frequency and wide area grid monitoring,the detection of heavy metals has the problems of high cost,complex process and secondary pollution.A wide spectrometry on-line monitoring technology of heavy metals in water quality with wide wavelength range,many detection parameters,fast speed and no secondary pollution is proposed.Based on Lambert Beer law,the on-line monitoring system of heavy metals based on embedded technology is designed by using sequential injection method and wide spectrometry detection technology,It includes water sample sampling unit,spectrum detection unit,data acquisition and processing unit,remote data transmission and control unit and upper computer software design;In view of the redundant data and noise interference existing in the complex water environment and on-line monitoring system,the wavelet transform and Hilbert-Huang Transform conversion method are used for the noise reduction and comparative analysis of wide spectrum monitoring data,and the Hilbert-Huang Transform is determined as the noise reduction method of wide spectrum data.The monitoring system is tested and analyzed through a large number of experiments,and the mathematical model of absorbance concentration of hexavalent chromium ion and lead ion is established.The fitting degree of linear equation of hexavalent chromium ion is 0.999,the indication error is 1.4%,the precision is 2.1%,the zero drift is 1.4%,and the range drift is 1.75%;The fitting degree of lead ion linear equation is 0.9982,the indication error is 3.68%,the precision is 3.4%,the zero drift is 4.2%,and the range drift is 3.55%.The performance test indicators of the monitoring system meet the requirements of national standards.