Determination and Traceability of Black Carbon in Soil Around a Coal-fired Power Plant

The combination of flotation and chemical oxidation is suitable for extracting black carbon (BC) from the soil around coal-fired power plant. In present study, the content of BC was determined by loss on ignition (LOI) method and potassium dichromate volumetric (PDV) method. Four extraction methods of BC were compared and the extracted BC was characterized by XRD, FTIR, SEM, and XPS. The findings reveal that the BC content obtained through the three chemical oxidation methods ranges from 14.51 to 22.25 g·kg, 13.10 to 19.28 g·kg, and 19.75 to 35.79 g·kg, respectively. The BC content obtained by combining flotation and chemical oxidation ranges from 44.04 to 50.60 g·kg, indicating that the combination method is more convenient for BC extraction from soil. The BC content measured by the LOI method is higher. The mineral compositions of fly ash from Kanshan power plant (KFA), BC, and soil minerals are similar and main minerals are quartz, magnetite, and hematite. The surface of both KFA and BC mainly comprises elements such as C, O, N, and Si. These results shows that the BC in the soil maybe originate from fly ash of the power plant. It is of great significance for environmental monitoring and pollution control around coal-fired power plants.