Determination And Degradation Of Benzo [a] Pyrene In Coal Tar Pitch For Road

Coal tar pitch for road construction is an vital bituminous material,which has been widely used for paving roads with the characteristics of excellent binder force to sand,anti-corrosion and aging resistance.However,Coal tar pitch is recently limited in road construction in some degree because of the strongly carcinogenic activity components.In this paper,study on determinating the benzo[a]pyrene(BaP)content in coal tar pitch by ultraviolet method and gas chromatographic method was made and compared,and on this basis,study on decrease of benzo[a]pyrene in coal tar pitch was also carried on.traditional ultraviolet method in which the background absorption of distracters was deducted by empirical formula may produce error.Determination of BaP in coal tar pitch by using soxhlet extraction and twice column chromatography cleanup coupled with UV-vis spectrophotometer were set up to replace empirical formula method and the sample extract process was optimized to improve accuracy.A new gas chromatography method was chosen to simplify the experiment process.Sample preparation technology was optimized and the chromatographic conditions were choosed;DB-5 chromatographic column was used first time to separate BaP from the distractors,and Standard addition method was utilized to calculate the BaP content in coal tar pitch.Polyethylene glycol(PEG)with different molecular weight were used to decrease the BaP content in coal tar pitch,and the reaction condition was optimized.Nano ZnO was also discussed to reduce the BaP in coal tar pitch,and the results show that nano ZnO has good performance in inhibition of the volatilization of asphalt smoke.These achievement provides possible approachs to reduce pollution caused by coal tar pitch.