Systems and methods for detecting and/or removing selenate from an aqueous selenate-containing solution are described. The method includes adding sufficient acid to the aqueous selenate-containing solution to acidify the aqueous selenate-containing solution; contacting the acidic aqueous selenate-containing solution with an underpotantial deposited copper-coated electrode; and removing selenate from the aqueous selenate-containing solution by forming copper-selenide on the underpotential copper-coated electrode.