Simultaneous decolorization and degradation of azo dye with electricity generation in microbial fuel cells

Dye wastewater is representative of highly colored effluent that is resistant to bio degradation and should be decolorized before discharge. The investigation into the decolorization and degradation of simulated dye wastewater containing the azo dye C.I. Acid Orange 7 (AO7) with simultaneous electricity generation in microbial fuel cells (MFCs) is described. Electrons obtained from organics oxidation were consumed for AO7 decolorization and electricity generation in the MFCs. The maximum power density obtained was 5.0 W/m³ for single-chamber MFCs employing glucose as fuel with the presentation of AO7. Nearly complete decolorization and degradation (97%) were achieved after 168 h operation. Furthermore, the decolorization efficiencies increased by factors of about 1.7 and 1.1, comparing the color absorbance with adsorption by granular graphite and open-circuit MFCs, respectively. Results indicate that MFCs can enhance decolorization and degradation of azo dyes such as AO7 with electricity generation compared with traditional methods, providing an effective alternative for dye wastewater treatment and energy recovery.