Study On The Detection Method Of Carbon Disulfide Based On Ultraviolet Absorption Spectroscopy

Carbon disulfide,acting as a kind of organic solvents and chemical raw materials with high volatility,is widely used in chemical industry,manufacturing and laboratory research.It is one of the main atmospheric sulfur gas pollutants in our country.Meanwhile,it has been proved to be of great application value in the field of fault diagnosis of high voltage insulated electrical equipment and medical diagnosis.The safe operation of high voltage insulated electrical equipment is of great significance to the national strategy of west-east power transmission for China.Proceeding from the national conditions of our country,the high precise detection of carbon disulfide is particularly important in many fields such as environmental protection,human health and power grid safety.Also,by taking carbon disulfide as an example,research on the high-precise trace gas detection method is helpful to the developments of detection method and gas analysis instrument for other pollutants.Among numerous gas detection technologies,ultraviolet absorption spectroscopy with excellent application prospect has been widely recognized in the gas detection field for its non-contact,short response time,high reliability.In this paper,systematic researches on the carbon disulfide detection method based on ultraviolet absorption spectroscopy are carried out by using multi-wavelength least square method(MWLSM),multi-wavelength least square method for multi-components(MC-MWLSM),and integral spectroscopy method(ISM).Effects of pressure on the ultraviolet absorption characteristics and measurement capability of carbon disulfide are studied.Combined with the uncertainty analysis of the measurement results,the reason of using 198-207 nm region to carry out high-precise carbon disulfide detection is explained theoretically.In order to study the influence of pressure on the measurement capability of carbon disulfide,a detection limit of 1 ppb?m and a relative uncertainty of 0.06% are obtained based on the absorption in the wavelength region of 198-207 nm using MWLSM for carbon disulfide detection at normal pressure.Pressure has no effect on the ultraviolet absorption of carbon disulfide is confirmed by analyzing the changes of carbon disulfide absorption spectrum shape and intensity with pressure.By comparing the gas measurement capability underdifferent pressure conditions,the measurement capacity of carbon disulfide is found to be independent of pressure.To study the detection of carbon disulfide in the atmosphere with spectral interference and the effects of ultraviolet photocatalysis on the measurement results of carbon disulfide,the effects of sulfur dioxide on the measurement results of carbon disulfide are studied and corresponding modification methods are established.Detection limits of 1 ppb?m and 9 ppb?m are obtained for carbon disulfide and sulfur dioxide respectively with the absorption in 198-220 nm using MC-MWLSM by single-component sensing.Modified formulas for measurement results of multiple components with interactional spectral characteristics are established.Simultaneous measurement of carbon disulfide and sulfur dioxide with high precision is realized.To study the ultraviolet photocatalysis of carbon disulfide in aerobic environment,a high precision oxygen detection method is developed.An oxygen detection method with high precision is proposed based on ultraviolet differential optical absorption spectroscopy.By using ISM,a detection limit of 150 ppm?m and relative uncertainty of0.6% are obtained for the sensing system operated in air environment,and those for the system operated in nitrogen protected environment are 24 ppm?m and 0.6%.The high precision measurement of oxygen in ppm is realized.The nonlinear absorption of oxygen in the open optical light path is the reason for the attenuation of oxygen absorption in the sample cell of the detection system without nitrogen protection.Combining with the pressure unaffected ultraviolet absorption characteristics of gas,as a multi-function design,a pressure detection method based on gas absorption is proposed.Taking 21% oxygen as an example,a pressure measurement capability of 180 Pa is obtained.The ultraviolet photocatalysis of carbon disulfide and the effect of ultraviolet photocatalysis on the static measurement results are studied.By analyzing the time-varying spectrum of oxygen during the ultraviolet photocatalytic process,the ultraviolet conversion of oxygen is caused by the excitation of oxygen by ultraviolet light below 220 nm is confirmed.Based on the linear relationship between the rate of ozone production and the initial concentration of oxygen,the ultraviolet photocatalytic of oxygen is confirmed to be first-order chemical reaction kinetic process.Combined with the ultraviolet photocatalytic time-varying spectrum of carbon disulfide,the conversion mechanism of carbon disulfide is revealed to be the oxidation of carbondisulfide by excited oxygen.Oxygen and carbon disulfide have the effects of hindering and promoting the conversion of carbon disulfide,respectively.A definite relationship,not affected by the oxygen concentration,between the equilibrium concentration of sulfur dioxide and the initial concentration of carbon disulfide is obtained.The detection method of carbon disulfide based on ultraviolet absorption spectroscopy is confirmed to be also applicable to the static measurement of carbon disulfide.By taking the 1%concentration deviation caused by catalysis as the benchmark,the static measurement condition of spectral acquisition time no more than 1 s is determined.