Study on Treatment of Groundwater Containing Cr(VI) by Different Mediums: The Case of Waste-Iron Chippings and Fly Ash

Waste iron chippings and fly ash can be used to remove Cr(VI) in groundwater, lab experiments show that, without changing the pH of groundwater, the compound mediator of waste-iron chippings + fly ash has better effects on wiping off the Cr(VI) in water than pure waste-iron chippings or fly ash. The disposal efficiency of the compound mediator can reach 97 percent. And the repetitive results of the experiments can be achieved. Based on the analysis, we concludes: 1.Iron chippings and fly ash can compose many primary cells, which can deoxidize Cr(VI) to Cr(III) and form Cr(OH)3 deposits under the condition of alkalescency; 2. Cr(VI) in water can be reduce to Cr(III) by Fe2+; 3. Fe2+ and Fe3+ generated by electrode reaction are good flocculation agents and can react into multiform alkali salts which capture weeny suspending granules, and finally form sedimentation and subside.