Agarwal, Arvind. CHARACTERIZATION OF SELENIUM FOR ITS REMOVAL FROM WATER
Department of Applied Sciences, M.N.R.Engineering College, Allahabad, U.P.,
211004 INDIA (arvind@ganga.mnrec.ernet.in)
The Extended X-ray Absorption Fine Structure (EXAFS) gives information about the local structure around the specific absorbing atom, and also to determine absorber-scatterer distances. The position, shape and EXAFS of X-ray absorption discontinuities have been used to deduce structural and chemical bonding information in different kind of materials. Crude oil from reservoirs containing seleniferous marine shales during refining transmits selenium in the process/waste water as selenocyanate, which has to be removed. In the treatment process by cupric salts, cupric ions are reduced by sodium thiosulfate and sodium thiosulfites initially present in the solution to form cuprous thiocyanate/selenocyanate. XAS has been used in the characterization of precipitate of copper-selenium obtained during water treatment. EXAFS analysis shows that selenium is present as selenide and surrounded by one nearest C atom and three next nearest Cu atoms.