Reduction of Chromium(VI) mediated by zero-valent magnesium under neutral pH conditions

► A low dose of ZVMg (50 mg/L) completely reduced Cr(VI) (≤10 μM) in 60 min at pH 7. ► Incomplete reduction at higher Cr(VI) conc. was due to surface passivation of ZVMg. ► Cr(VI) reduction rate was not decreased in the presence of dissolved oxygen. ► Cr(VI) was not reduced directly by ZVMg but by intermediates of ZVMg-water reaction. ► Potential intermediate species responsible for Cr(VI) reduction were discussed.