Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is stil...Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is still a challenge to figure out the contributions and originating regions for different sources of atmospheric NACs.Here,field observations on fine particulate NACs were conducted at a coastal rural area in Qingdao,China in the winter of 2018 and 2019.The mean total concentrations of fine particulate nitro-aromatic compounds were 125.0±89.5 and 27.7±21.1 ng/m^(3)in the winter of 2018 and 2019,respectively.Among the measured eleven NACs,nitrophenols and nitrocatechols were the most abundant species.Variation characteristics and correlation analysis showed that humidity and anthropogenic primary emissions had significant influences on the NAC abundances.In this study,two tracing methods of the improved spatial concentration weighted trajectory(SCWT)model and the receptor model of positive matrix factorization(PMF)were combined to comprehensively understand the origins of NACs in fine particles at coastal Qingdao.Four major sources were identified,including coal combustion,biomass burning,vehicle exhaust,and secondary formation.Surprisingly,coal combustion was responsible for about half of the observed nitro-aromatic compounds,followed by biomass burning(~30%).The results by SCWT demonstrated that the coal combustion dominated NACs mainly originated from the Shandong peninsula and the areas to the north and southwest,while those dominated by biomass burning primarily came from local Qingdao and the areas to the west.展开更多
Nitro-aromatic compounds can be photocatalytically reduced into the corresponding amine-aromatic com- pounds using TiO2 as a photocatalyst in the UV/TiO2/holes scavenger and Vis/TiO2/dye-sensitized systems. In the UV/...Nitro-aromatic compounds can be photocatalytically reduced into the corresponding amine-aromatic com- pounds using TiO2 as a photocatalyst in the UV/TiO2/holes scavenger and Vis/TiO2/dye-sensitized systems. In the UV/TiO2/holes scavenger system, reaction substrate alcohols such as methanol could be used as the holes scavengers, and in the Vis/TiO2/dye-sensitized system, substrate alcohols could be oxidized to the corresponding aldehydes with high selectivity. When methanol was used as the holes scavengers and the illumination time was 6 h, 87.2% ofp-nitrotoluene could be photocatalytically reduced into p-toluidine. In the Vis/TiO2/dye-sensitized system, the effect of aromatic alcohols for the photocatalytic reduction of nitrobenzene was better than that of other alcohols At the same time, aromatic alcohols can be easily oxidized, and the production efficiencies of the corresponding aldehydes were higher than those of other alcohols. The possible reaction mechanisms were also proposed.展开更多
I Introduction The abnormal photoreaction property of o-nitrobenzaldehyde, which is one of the standard scintillators and the reference material in quantum etficient measurement of photochernistry, has been paid much ...I Introduction The abnormal photoreaction property of o-nitrobenzaldehyde, which is one of the standard scintillators and the reference material in quantum etficient measurement of photochernistry, has been paid much attention to. Up to now, however, its photoreaction mechanism has not been cleared yet. Tech et al observed the ESR spectrum produced in the photochemical reaction of alcohol solution of o-nitrobenzaldehyde, but they did not展开更多
基金supported by the Natural Science Foundation of Shandong Province (No.ZR2020YQ30)the National Natural Science Foundation of China (Nos.42005089,41775118)+1 种基金the Youth Innovation Program of Universities in Shandong Province (No.2019KJD007)received financial support from Shandong University (No.2020QNQT012)。
文摘Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is still a challenge to figure out the contributions and originating regions for different sources of atmospheric NACs.Here,field observations on fine particulate NACs were conducted at a coastal rural area in Qingdao,China in the winter of 2018 and 2019.The mean total concentrations of fine particulate nitro-aromatic compounds were 125.0±89.5 and 27.7±21.1 ng/m^(3)in the winter of 2018 and 2019,respectively.Among the measured eleven NACs,nitrophenols and nitrocatechols were the most abundant species.Variation characteristics and correlation analysis showed that humidity and anthropogenic primary emissions had significant influences on the NAC abundances.In this study,two tracing methods of the improved spatial concentration weighted trajectory(SCWT)model and the receptor model of positive matrix factorization(PMF)were combined to comprehensively understand the origins of NACs in fine particles at coastal Qingdao.Four major sources were identified,including coal combustion,biomass burning,vehicle exhaust,and secondary formation.Surprisingly,coal combustion was responsible for about half of the observed nitro-aromatic compounds,followed by biomass burning(~30%).The results by SCWT demonstrated that the coal combustion dominated NACs mainly originated from the Shandong peninsula and the areas to the north and southwest,while those dominated by biomass burning primarily came from local Qingdao and the areas to the west.
基金Project supported by the National Natural Science Foundation of China （Nos. 20673042, 20973071） and the Key Project of Science and Technology Research of Ministry of Education of China （208062）.
文摘Nitro-aromatic compounds can be photocatalytically reduced into the corresponding amine-aromatic com- pounds using TiO2 as a photocatalyst in the UV/TiO2/holes scavenger and Vis/TiO2/dye-sensitized systems. In the UV/TiO2/holes scavenger system, reaction substrate alcohols such as methanol could be used as the holes scavengers, and in the Vis/TiO2/dye-sensitized system, substrate alcohols could be oxidized to the corresponding aldehydes with high selectivity. When methanol was used as the holes scavengers and the illumination time was 6 h, 87.2% ofp-nitrotoluene could be photocatalytically reduced into p-toluidine. In the Vis/TiO2/dye-sensitized system, the effect of aromatic alcohols for the photocatalytic reduction of nitrobenzene was better than that of other alcohols At the same time, aromatic alcohols can be easily oxidized, and the production efficiencies of the corresponding aldehydes were higher than those of other alcohols. The possible reaction mechanisms were also proposed.
基金Project supported by the National Natural Science Foundation of China.
文摘I Introduction The abnormal photoreaction property of o-nitrobenzaldehyde, which is one of the standard scintillators and the reference material in quantum etficient measurement of photochernistry, has been paid much attention to. Up to now, however, its photoreaction mechanism has not been cleared yet. Tech et al observed the ESR spectrum produced in the photochemical reaction of alcohol solution of o-nitrobenzaldehyde, but they did not
