title: Chemical forms of the fluorine, chlorine, oxygen and carbon in coal fly ash and their correlations with mercury retention.
abstract: Fly ashes recovered from the particulate control devices at six pulverized coal boiler unites of China, are studied using an X-ray photoelectron spectroscopy (XPS) with a particular focus on the functionalities of fluorine (F), chlorine (Cl), carbon and oxygen on fly ash. It is found that the inorganic forms of F and Cl are predominant on the ash surface in comparison with their organics, and the proportion of organic Cl is relatively higher than that of organic F. Similar results are also obtained in the bulk by correlating the F and Cl contents with those of the unburnt carbon and other compositions in ash. Strong correlations of mercury retention with surface carbon-oxygen functional groups indicate that the C=O, OH/C-O and (O-C=O)-O on surface are of significant importance for mercury retention in fly ash. Their surface concentrations are related to coal type. The presence of Cl in fly ash helps with mercury retention. No obvious effect of F is observed.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, China; Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Deng
authors.affiliation: Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Shu
authors.affiliation: State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: sgli@ipe.ac.cn.
authors.forename: Songgeng
authors.initials: S
authors.lastname: Li
authors.affiliation: Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Tian
authors.affiliation: Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Jiayu
authors.initials: J
authors.lastname: Huang
authors.affiliation: Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: zhangfan5188@vip.sina.com.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
keywords: Chlorine; Coal fly ash; Fluorine; Mercury retention; Surface functionality