Removal of selenocyanate from water using elemental iron

Batch experiments were conducted to investigate the removal of selenocyanate (SeCN−) from oil refinery wastewater and artificial wastewater with elemental iron [Fe(0)]. The chemical forms of selenium in the reacted solids were determined with X-ray photoelectron spectroscopy (XPS) and a sulfite extraction procedure. SeCN− was effectively removed from the wastewater with Fe(0) filings when the water pH was controlled at approximately 6. SeCN− was removed by Fe(0) through the formation of elemental selenium [Se(0)] and ferrous selenide. The possible chemical reactions between SeCN− and Fe(0) included deselenation of SeCN− and electrochemical reduction of Se(0) to selenide. A cost-effective process may be developed for the treatment of SeCN− in wastewater using Fe(0).