In this study, removal of Hg2+ as an electron acceptor of a microbial fuel cell (MFC) was successfully achieved. The initial pH affected the removal efficiency of Hg2+ from electrochemical and chemical reactions. The effluent Hg concentrations for initial Hg2+ concentration of 50 mg/L after a 5-h reaction were 3.08 +/- 0.07, 4.21 +/- 0.34, 4.84 +/- 0.00, and 5.25 +/- 0.36 mg/L for initial pH of 2, 3, 4, and 4.8, respectively. For 10-h reaction, the effluent Hg concentration was in the range of 0.44-0.69 mg/L, for different initial Hg2+ concentrations (25, 50, and 100 mg/L). Lower initial pH and higher Hg2+ concentration resulted in larger maximum power density. A maximum power density of 433.1 mW/m(2) was achieved from 100 mg/L Hg2+ at pH 2. (C) 2011 Elsevier Ltd. All rights reserved.