Bioelectrochemical treatment of acid mine drainage dominated with iron.
Treatment of acid mine drainage (AMD) dominated with iron (Fe), the most common metal, is a long-term expensive commitment, the goal of which is to increase the pH and remove Fe. In the present study, a proton exchange membrane microbial fuel cell (MFC) showed promise for the efficient treatment of an AMD dominated with ferric iron (pH 2.4±0.1; 500 mg L(-1) Fe(3+)). Briefly, Fe(3+) was reduced to Fe(2+) at the cathode of the MFC, followed by Fe(2+) re-oxidation and precipitation as oxy(hydroxi)des. Oxygen reduction and cation transfer to the cathode of the MFC further caused a rise in pH. A linear relationship was observed between the charge transferred in the MFC and the performance of the system up to 880 C. Optimal conditions were found at a charge of 662 C, achieved within 7 d at an acetate concentration of 1.6 g L(-1) in a membrane MFC. This caused the pH to rise to 7.9 and resulted in a Fe removal of 99%. Treated effluent met the pH discharge limits of 6.5-9. The maximum power generation achieved under these conditions averaged 8.6±2.3 W m(-3), which could help reduce the costs of full-scale bioelectrochemical treatment of AMD dominated with Fe.
Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Dr. 2, Singapore 117576, Singapore.
Olivier
O
Lefebvre
Carmen M
CM
Neculita
Xiaodi
X
Yue
How Yong
HY
Ng
D000143:Acids; D001674:Bioelectric Energy Sources; D004323:Drainage, Sanitary / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods*; D005290:Ferric Compounds / Q000032:analysis / Q000737:chemistry; D005296:Ferrous Compounds / Q000032:analysis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis / Q000517:prevention & control; D007501:Iron / Q000032:analysis* / Q000737:chemistry; D008567:Membranes, Artificial; D008906:Mining; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
D000143:Acids; D005290:Ferric Compounds; D005296:Ferrous Compounds; D007220:Industrial Waste; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical; D007501:Iron