Article Abstract:
The complex chemistry of selenium (Se) in the environment reduces the success rate of various bioremediation techniques. Se has multiple oxidation states and surface adsorption properties. In water, Se occurs in stable form as selenate (Se(IV)). Experiments studying the chemistry of Se(IV) reveal reveal that Se(IV) is formed thru rapid transformations, but also disappears rapidly in the presence of a reducing agent such as birnessite via oxidation through a surface mechanism. The rate of disappearance of Se(IV) is influenced by temperature and pH.
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Article Abstract:
The presence of selenite and selenate in coal fly ash extracts was investigated using a new ion chromatography technique. The technique used a Dionex AG5 guard column and an AS4A separator column to separate the anions. In addition, an eluant comprised of 2.0mM sodium carbonate and 1.0mM sodium hydroxide was also used. The method was capable of separating selenium specie without any interference problems from nitrate, phosphate and sulfate.
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Article Abstract:
Selenium is a naturally occurring, toxic trace element that is valuable in different natural and agricultural environments. Greater information on selenium speciation can be derived by using synchrotron radiation-based X-ray absorption (XAS) spectroscopy methods. XAS methods have been established for structural and electronic environments through various systems and are ideal for quantitative speciation of environmental contaminants.
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