Huggins Frank E, Senior Constance L, Chu Paul, Ladwig Ken, Huffman Gerald P
CFFS/CME, University of Kentucky, Lexington, Kentucky 40506, USA.
Environ Sci Technol. 2007 May 1;41(9):3284-9. doi: 10.1021/es062069y.
X-ray absorption fine structure spectroscopy has been used to determine directly the oxidation states and speciation of selenium and arsenic in 10 fly ash samples collected from full-scale utility plants. Such information is needed to assess the health risk posed by these elements in fly ash and to understand their behavior during combustion and in fly ash disposal options, such as sequestration in tailings ponds. Selenium is found predominantly as Se(IV) in selenite (SeO3(2-)) species, whereas arsenic is found predominantly as As(V) in arsenate (AsO4(3-)) species. Two distinct types of selenite and arsenate spectra were observed depending upon whether the fly ash was derived from eastern U.S. bituminous (Fe-rich) coals or from western subbituminous or lignite (Ca-rich) coals. Similar spectral details were observed for both arsenic and selenium in the two different types of fly ash, suggesting that the postcombustion behavior and capture of both of these elements are likely controlled by the same dominant element or phase in each type of fly ash.
X射线吸收精细结构光谱已被用于直接测定从大型公用事业工厂收集的10个粉煤灰样品中硒和砷的氧化态及形态。评估粉煤灰中这些元素所带来的健康风险以及了解它们在燃烧过程中和粉煤灰处置选项（如尾矿库封存）中的行为，都需要此类信息。硒主要以亚硒酸盐（SeO3(2-)）物种中的Se(IV)形式存在，而砷主要以砷酸盐（AsO4(3-)）物种中的As(V)形式存在。根据粉煤灰是源自美国东部的烟煤（富铁煤）还是西部的次烟煤或褐煤（富钙煤），观察到了两种不同类型的亚硒酸盐和砷酸盐光谱。在两种不同类型的粉煤灰中，砷和硒都观察到了类似的光谱细节，这表明这两种元素在燃烧后的行为及捕获可能受每种类型粉煤灰中相同的主导元素或相控制。
