Research On Determination Technology Of Petroleum Product Pollutants Based On Fluorescence Spectra

Petroleum products,such as gasoline,diesel,engine oil and other refined oils processed from crude oil are important sources of water pollution.With the development of transportation industry,increasing demand for petroleum products has led to increasing number of pollution incidents in every link of production and use.Rapid and effective detection of oil pollution is of great significance to protect water resources and human health.The fluorescence spectrometry method is rapid and sensitive.Fluorescence spectrometry combined with chemometrics to analyze high dimensional data array has provided the possibility for the detection of petroleum product pollutant in complex system.This research work follows up the field of high-order calibration,applying a variety of calibration methods in three dimensional fluorescence spectra of mixed oil pollutants to realize accurate resolution and concentration prediction of different oils.And based on the mechanism of the impact of temperature on petroleum product fluorescence,temperature information is introduced to construct the four dimensional fluorescence spectrum data array.The method of four dimensional fluorescence spectrometry for petroleum product pollutant determination is studied.Based on the mechanism of photoluminescence,the influence factors of fluorescence intensity are analyzed in terms of molecular structure and environment.The effect of temperature on the fluorescence is analyzed,which is the theoretical basis of four dimensional fluorescence spectrometry.According to the Lambert-Beer law,quantitative relationship between fluorescence intensity and sample concentration is studied,and the detection mechanism of fluorescence spectrometry for petroleum product pollutants is demonstrated.The characteristics of different fluorescence determination techniques are analyzed,and the research status of four dimensional fluorescence spectrometry provides theoretical basis for the development of four dimensional fluorescence spectrometry by introducing temperature information for petroleum product pollutant determination.The detection parameters for petroleum product samples are optimized.Excitation channel and emission channel spectrum correction,Rayleigh scattering and Raman scattering interference spectra removal methods are proposed.In view of the fact that the fluorescence signal is easily affected by noise in the detection of petroleum product pollutant in water,an improved wavelet threshold transform denoising method is proposed by introducing a regulating factor.Compared with the traditional discrete wavelet transform and empirical mode decomposition denoising method,it is effective for the spectrum denoising for petroleum product.Furthermore,in the aspect of denoising time the lifting algorithm transform shows the advantage of speedability.The mixing of humic acid with multiple petroleum product pollutants can lead to the problem of spectral overlap.Three dimensional fluorescence spectroscopy combined with the second-order calibration method can be used to realize multivariate calibration of the target components in the presence with interference,which is an effective way to solve the above problem in the mixed pollutants determination.Second-order calibration PARAFAC algorithm,alternating penalty trilinear decomposition(APTLD)algorithm and self-weighted alternating trilinear decomposition(SWATLD)algorithm,are applied to the fluorescence spectroscopy determination of mixed system with gasoline,diesel,engine oil and humic acid interference.Their results of species resolution and concentration quantification of each petroleum product are compared,and the performance of different algorithms is evaluated by figures of merit(FOM),so as to improve its application in the fluorescence spectroscopy for mixed petroleum product pollutants determination.According to the dimension advantage that quantitative selectivity will increase with the increase of dimension in the theory of signal analysis,temperature information as one more dimension added to the three dimensional fluorescence spectroscopy to structure excitation wavelength-emission wavelength-temperature-sample data array of the four dimensional fluorescence spectrometry determination method is proposed.Experiments show that in the range of 15?~25?,spectrum shape of petroleum product doesn't change with temperature but intensity increases with temperature decreases,which satisfy the requirement of quadrilinear,providing the possibility for building four dimensional fluorescence spectrometry.Compared with the results of three dimensional spectrometry determination,four dimensional fluorescence spectrum data array with temperatureinformation improves the extraction ability of inner information,avoids the temperature correction in conventional fluorescence spectrum spectrometry method,and has important significance for exploring fast and accurate petroleum product pollutant determination method.