The Measurement Method Of Volatiles From Agricultural Plastics Using Infrared Spectroscopy

Agricultural plastic film volatiles have become one of the sources of air pollution.Rapid and accurate detection of plastic film volatiles is of great help to the study of the formation mechanism of air pollution and the formulation of related pollution prevention and control policies and regulations.As an efficient gas detection technology,Fourier Transform Infrared Spectroscopy(FTIR)has the advantages of fast,high sensitivity,high resolution,and multi-component measurement.It can detect trace gases in situ and quickly.This thesis embarks from the plastic volatiles,the infrared spectral characteristics of"point-line-surface"measurement,by using FTIR technology under the different ways of measuring film plastic volatiles detection method,obtained under the different ways of measuring film plastic volatiles of infrared absorption spectrum,clear the FTIR spectrum absorption characteristics of the plastic film volatiles,implements the plastic volatiles of"point","line"and"surface"test.The main research work of this paper is as follows:1.A high sensitivity method of long optical path FTIR extraction for the determination of plastics volatiles was proposed.According to the characteristics of low concentration of plastic volatiles,the effective optical path was increased to 20 m by using multiple reflection White cell,and the highly sensitive measurement of plastic volatiles was carried out.At room temperature and heating conditions,the use of the removable long optical path FTIR measurement system,and respectively obtain the infrared spectrum of the five kinds of plastic volatile gas,combining with chemometrics algorithms parsing their absorption characteristics of the plastic volatiles,investigate the plastic potential of gas in the volatile components,and the spectrum of potential gas absorption characteristics and the National Institute of Standards and Technology(National Institute of Standards and Technology,NIST)corresponding gas in the spectral library of standard compare the infrared absorption spectrum,The gas components in 5 kinds of volatile plastics were identified.2.An active Open Path Fourier Transform Infrared Spectroscopy(OP-FTIR)method for the determination of plastic volatiles was proposed.In the open path,the active OP-FTIR system was used to continuously monitor the volatiles released by five kinds of plastics after heating,and the infrared absorption spectra of volatiles were obtained.By comparing the infrared absorption characteristics of plastic volatiles measured by the OP-FTIR method and the long optical path FTIR method,the results show that the spectral absorption characteristics of plastic volatiles obtained by the two methods are the same,which verifies the feasibility of the active OP-FTIR method for measuring plastic volatiles.Relative to the long optical path FTIR measurement method,while the OP-FTIR method of plastic volatiles spectral absorption characteristic peak amplitude is weak,but the method need not extract plastic volatiles into the gas cell,open space can be realized in the specific path of plastic volatiles of remote telemetry,achieve the"line"measuring plastic volatiles.3.A method of detecting plastic volatiles using OP-FTIR imaging technology was proposed.In the above two work to achieve plastic volatiles"point"and"line",based on combining infrared focal plane array imaging detector with Fourier transform spectroscopy,using long-wave infrared imaging Fourier transform(LWIR-IFT)technology in normal temperature and high temperature two in the access to the open space under the environment of 5 kinds of plastic volatiles of infrared imaging Fourier transform spectrum data,which is used to analyze the distribution of open space in the plastic volatiles.Through the analysis of the two-dimensional space and radiation brightness temperature data of plastic volatiles,it is shown that the infrared absorption characteristics are the same as those observed by the previous two methods near 1100 cm^-1.On this basis,an identification plastic volatiles of Fourier transform infrared imaging spectral characteristics of the software,which can realize the visualization of the spatial distribution of 2 dimension target gases,and with visible image fusion,intuitive show the plastic state of the spatial distribution of volatile gas and emissions,can for visual monitoring of the target gas,implement"surface"measuring plastic volatiles.The results of the three measurement methods all showed that the plastic volatiles had obvious absorption characteristics of the infrared spectrum,and it was feasible to use the infrared spectrum to monitor the volatiles of plastic mulching film in farmland.And,more importantly,we through the removable long optical path FTIR,OP-FTIR and LWIR-IFT the three measuring methods,respectively plastic volatiles of point,line measurement has verified the feasibility of visualization and distribution,plastic volatiles continuous emissions monitoring system,is established for agricultural mulch plastic volatiles of atmospheric environmental impact related research work provides a new method and theoretical support and technical support.