The Research For Light Absorption Of Black Carbon And Absorptionenhancenent Of Black Carbon Coated By Organic Carbon In The Laboratory

Carbonaceous aerosol is generally divided into three categories:black carbon(BC),organic carbon(OC)and carbonate.A fraction of OC can absorb ultraviolet-visible light,named as brown carbon(BrC).BC and BrC can absorb light to produce positive radiative forcing and warm the atmosphere.Therefore,optical properties of BC and BrC become one of the hot spots in the atmosphere research.The mixture of BC and OC leads OC coating on BC,which may increase the mass absorption efficiency of BC and results in its light absorption enhancement.The evaluation of the light absorption enhancement of carbonaceous aerosol caused by mixed state has a greater uncertainty at home and abroad,which can produce a certain influence on the assessment of climate effect of BC.The main contents of this study are as follows:(1)The size and morphology of BC obtained by kerosene combustion were characterized by transmission electron microscope,and the infrared spectra measurement of BC were done.(2)AE-31 and OC/EC carbon analyzer were used to measure BC concentration in the experiment,and the correlation and difference of the data between the two kinds of instruments had been discussed.(3)The formation of BrC by the reaction of glycolaldehyde and glycine was studied by UV-vis spectrophotometer.The formation mechanism of BrC was analyzed.(4)The light absorptions of BC before and after coated by OC were investigated,respectively.(5)The Angstrom indexes of OC in BC obtained by kerosene combustion and OC coating on BC were calculated,respectively and the contributions of OC to BC mass absorption efficiency were determined,respectively.The results showed that the diameter of BC was 43.09 nm,and the structure of BC from kerosene combustion and other fossil fuel combustion was similar.There was a good correlation for BC concentrations obtained through aethalometer AE-31 and OC/EC carbon analyzer.OC in BC generated by kerosene combustion can enhance the mass absorption efficiency of BC and OC from the mixed solution coated on BC enhanced more mass absorption efficiency of BC,which contributed 4.1-7%and 9.3-14.7%to BC light absorption,respectively.