Abstract:Characterized with properties of extensive production, high toxicity, and easy formation of comprehensive pollution between water and soil, industrial Cr(Ⅵ) water pollution has attracted great attention of environmentalists all over the world. The green and low-cost treatment of Cr(Ⅵ) containing wastewater has become one of hottest and most difficult issue that should be solved. In this study, electrocoagulation method was introduced to remove Cr(Ⅵ) from wastewater, and effects of operation conditions on Cr(Ⅵ) removal efficiency were comprehensively investigated, including pH value of solution, cell voltage, electrolyte concentration, and initial Cr(Ⅵ) concentration. Cr(Ⅵ) removal mechanism was explored through micro-morphology observation, element distribution test, and phase composition detection of precipitated flocs. The results show that Cr(Ⅵ) concentration in water outlet drops from initial 10.0 mg/L to 0.018 mg/L with 12 min electrocoagulation reaction with removal efficiency of 99.98% under the optimum condition including pH value of solution of 6.0, cell voltage of 3.0 V, and electrolyte concentration of 2%. Cr(Ⅵ) concentration in water outlet meets emission limit of drinking water. The mechanism analysis shows that Cr(Ⅵ) in wastewater is reduced to Cr(Ⅲ) by Fe2+, then the formed CrOOH and Cr(OH)3 species are captured and precipitated by iron oxides/hydroxides generated in electrocoagulation field. Electrocoagulation method for treatment of Cr(Ⅵ) pollution has the advantages of high removal efficiency, fast speed, and low sludge production, which can provide significant technical support for purification of Cr(Ⅵ) containing wastewater.