【摘要】 研究了我国西南地区小龙潭、阳宗海和贵阳三个燃煤电厂排放可吸入颗粒物(PM10)中重金属元素(As、Se、Be、Pb、Cd和Co)的分布与富集特征。同粒径大于10μm的飞灰相比,大多数重金属倾向于在PM10中富集。经历了挥发-凝聚过程的As、Se、Cd和Pb元素,在PM10粒径大小和化学成分差异等因素的共同作用下,随着PM10粒径的减小,其含量和富集系数在总体增大的趋势下局部存在低值异常;未经历挥发-凝聚过程的重金属元素(小龙潭电厂、贵阳电厂Be和Co)表现出在不同粒级PM10中均匀分布和正常富集的特征。煤粉燃烧过程中重金属元素的挥发-凝聚特性改变了燃煤产物中重金属元素的环境迁移能力,经历了挥发-凝聚过程的重金属元素主要赋存于飞灰表面,形成纳米级颗粒覆盖层,其水溶性和酸溶性增强,环境危害性增大。更多还原

【Abstract】 The distribution and enrichment characteristics of heavy metal elements(As,Se,Be,Pb,Cd and Co)in PM10,which was discharged from Xiaolongtan,Yangzonghai and Guiyang coal power plants in Southwest China,were studied.Compared with the fly ash with particle size > 10 μm,the PM10 enriches in heavy metal elements.Under the interaction of the particle size and the difference of chemical composition,the content and enrichment coefficient of As,Se,Cd and Pb which have undergone the volatilization-condensation process are prone to increase generally along with the particle size of PM10 decreased,but have some partial low abnormal values.Moreover,the elements which have not undergone the volatilization-condensation process(Be and Co from Xiaolongtan and Guiyang power plants)show the characteristics of homogeneous distribution and normal enrichment in PM10 of different particle sizes.The volatilization-condensation characteristics of heavy metal elements in the combustion process change the environment transfer ability of heavy metal elements in coal combustion disposals.After the process of volatilization-condensation,the heavy metal elements are more prone to accumulate and form the nanometer-sized overlay on fly ash,which is more water-soluble and acid-soluble,consequently have more powerful destructive ability towards environment than those elements which have not undergone that process.更多还原