| The development of industry has caused oil exploitation and transportation,which have increased with each passing day.The waste oil that discharged from factories,as well as large amounts of oil material leaked in the process of mining and oil transportation,endanger human health and environmental safety seriously.It is of great significance to determine the composition and content of oil pollutants accurately and efficiently for environmental monitoring and pollution control of water resources.The technology of fluorescence analysis has the characteristics of high measuring accuracy,less experimental samples and so on,which has been applied in the detection of water and soil.Based on the fluorescence spectra characteristic of oil pollutants,the three-dimensional fluorescence technique combined with the second order correction method is adopted to resolve the components and determine the content of oil pollutants in this paper.The validity of the method is verified by experiments.Based on the mechanism of photoluminescence,the effect of molecular structure and external environment on the fluorescence intensity is analyzed.The methods to improve the fluorescence intensity from internal and external factors are point out.According to the law of Lambert-Beer,the relationship between sample concentration and fluorescence intensity is studied.The existence forms of the oil components at different temperatures are analyzed,according to their component structure,the feasibility of using fluorescent technology to detect oil pollutants is demonstrated.The structure of fluorescence detector is studied,and the types and function characteristics of the light source,monochromator and photoelectric detector are compared.The FLS920 full function type fluorescence spectrometer is selected with spectral correction and denoising in this paper.The working parameters of spectrometer are set,and the wavelength correction methods of the monochromator,excitation channels and emission channel are put forward to.Focus on the mechanism of Rayleigh scattering and Raman scattering,the elimination schemes of two kinds of scattering are studied.For the noise signals contained in the fluorescence spectra,the stationary wavelet transform isadopted to retain the useful information,the high frequency signals are denoised by the improved dual threshold quantization function,and the low frequency signals denoised by the nonlinear filter based on the mathematical morphology,thus the spectral information is improved and detection accuracy is enhanced.In order to increase the solubility of oil in water and enhance its fluorescence properties,the micellar solution is adopted as the solvent of oil pollutants.The formation mechanism of micellar solution is studied,the best concentration of SDS micellar solution as solvent is obtained by experiments.The fluorescence spectra of typical oil pollutants in aqueous solution and in SDS micellar solution are compared,which proves the micellar solution has the characteristics of solubilization and enhancement of fluorescence intensity.The linear range of the relative fluorescence intensity with the change of the concentration of oil substance is studied quantitatively.The fitting curve of the relative fluorescence intensity and concentration is established.Aiming at the complexity of the oil pollutants composition,it is difficult to identify the components accurately and quantitatively by using the method of chemical experiments,thus the second order correction analysis method is proposed,replacing“ chemical separation ” with “mathematical separation”,in order to realize the detection of the different types of pollutants.The improved parallel factor analysis algorithm—the self weighted alternating trilinear decomposition(SWATLD)algorithm is proposed,which has the characteristics of non sensitive to the component numbers,strong noise immunity and so on.Experiments show that the SWATLD algorithm has good effect on the resolution of mixed components of oil pollutants. |
PDF Full Text Request