Effects of Electron Donors and Acceptors on Cr(VI) Removal in Biotic Fe0 Columns Preloaded with Microorganisms

The removal of Cr(VI) from groundwater by zero-valent iron (Fe0) and microorganisms under different nutrients electron-accepting conditions was investigated using continuously-flowed column reactors with an abiotic Fe0 as the control. Both biotic columns were operated at low relatively high concentrations organic substrates (sodium acetate humic acid) electron acceptors (nitrate sulfate). Sodium acid found to be effective for system remove since able gain extra reducing capacity two simultaneously avoid passivation effect on metabolizing it. For nitrate sulfate, varied influences observed in system. former showed apparent inhibition it competed electrons, became more severe while increased. Differently, highly reactive minerals such green rusts sulfide could generated surface sulfate-reducing condition. They significantly enhanced providing adsorptive reductive sites. Overall, though exhibited a longer life-span higher than column, effects should still taken into account when applying systems Cr(VI)-contaminated remediation.