Electroreduction of hexavalent chromium using a polypyrrole-modified electrode under potentiostatic and potentiodynamic conditions

► The removal of Cr(VI) using ppy-modified electrode and SS electrode were compared. ► The inhibiton effect of hydrogen formation on ppy saved more electrons for Cr(VI) reduction and improved the current efficiency. ► Extremely higher removal percentage and current efficiency were achieved on ppy. ► Cr(VI) was more effectively reduced under pontentiodynamic condition than potentiostatic condition.