Study On The Monitoring And Degradation Mechanisms Of Benzene And Its Alkyl Derivates

The study of ambient air pollution is one of the most important research topics on environmental science. The condition, source and its influence factors of volatile organic compounds (VOCs), especially the condition of benzene, and its alkyl derivatives in indoor air were researched in this paper. An analytical method for monitoring benzene and its alkyl derivates is established. This method consists of a little volume and low noise air sampling pump. The benzene and its alkyl derivates collected in the activated charcoal were extracted with carbon disulfide by mechanical shaking for 20 minutes. It was proved that the method of solvent extraction and capillary gas chromatographic determination satisfied the monitoring needs of the benzene and its alkyl derivates. The degradation of benzene and its alkyl derivates in different conditions were investigated.The main conclusions of this paper are as follows:(1 ) The pollution condition of benzene and its alkyl derivates of office, conference and laboratory were monitored and discussed its source and its influence factors were discussed. The monitor results indicated that the new decorated office was heavy polluted and benzene, toluene and xylene severity exceeded the standard. The high concentration of benzene and its alky derivates appeared in the morning, lower at noon and at dusk the concentration became higher. This was similar to the pollution of benzene and its alkyl derivates outside room.(2) Benzene and its alkyl derivates main sources were gooey used in indoor decoration. Benzene and xylene originated form chemical compounds such as coating and paints. Usually the airiness changes was one of the valid measures to lower the indoors pollutant.(3) The degradation rate of xylene was the highest, while benzene was the lowest. And among the m, o, p-xylene, the degradation of m-xylene was the highest, which was due to its molecule structure.(4) The degradation of benzene and its alkyl derivates was more efficientunder the collaboration function of UV and ozone than only UV or ozone. It was due to benzene and its carbon hydrogen absorbed UV energy and had oxidation reaction.(5) By comparing the photo-catalytic degradation efficiency of T1O2 powder and T1O2 film, the T1O2 film was more efficiency than T1O2 powder . It could be concluded from experimental results that T1O2 powder sheltered each other.(6) The dynamic experiment indicated that the degradation of benzene and it carbon hydrogen compounds accorded with dynamic model and its reaction rate related to its initial concentration.(7) The influence of reactor temperature on photo-degradation was studied and the results indicated that temperature had little influence on benzene and its alkyl derivates.(8) It could be indicated that the intermediate products of 0, m-xylene were benzene and toluene .Benzene was found during the photo-degradation of p-xylene and toluene through the GCMS equipment.