中国科学院地球环境研究所机构知识库

Fly ash and bottom ash samples were collected from a coal-fired power plant located in Anhui province, China. Mineral phases and morphologies of the samples were determined by X-ray diffraction and scanning electron microscopy, respectively. Sixteen polycyclic aromatic hydrocarbon (PAH; 16 compounds specified in United States Environmental Protection Agency Method 610) properties in ash samples were investigated. In fly ashes, a16PAH (total amount of 16 PAHs) and aCPAH (total amount of 8 carcinogenic PAHs) levels varied from 0.93 to 2.08 mu g/g and from 0.26 to 0.87 mu g/g, respectively. In bottom ashes, a16PAH and aCPAH levels varied from 2.83 to 5.32 and 1.76 to 3.76 mu g/g, respectively. Fly ashes were dominated by medium molecular-weight PAHs and low molecular-weight PAHs, whereas bottom ashes were abundant in 5- and 6-ring PAH species. The CPAHs levels of some ashes, especially bottom ashes, are greater than the limits regulated by several countries, indicating that this type of coal combustion product requires special treatment before landfill. PAH levels and patterns in fly ash were evidently affected by particle size, and total organic content had a closer correlation with PAH content than particle size in bottom and fly ash, which may be due to unburned carbon existing in bottom ash.