Eco-friendly decolorization of Indigo Carmine and Safranine-T dyes with bioenergy generation using a single-chamber microbial fuel cell
摘要
Developing sustainable technologies for treating dye-contaminated wastewater is an urgent requirement to reduce the water pollution and a major challenge due to the toxic and recalcitrant nature of most dyes. This study investigated the effect of concentration (50–500 mg L−1) and chemical nature of two model dyes—anionic Indigo Carmine (IC) and cationic Safranine-T (ST)—on decolorization, COD removal and bioelectricity generation in a single-chamber microbial fuel cell (MFC) equipped with a membrane electrode assembly (MEA) and inoculated with anaerobic sludge. The MFC achieved > 93% decolorization for ST at 500 mg L−1, while IC exhibited the highest COD removal (189.81 mg L−1, 36.82%), Coulombic efficiency (17.05%), and maximum output voltage (300 mV), power density (34.54 mW m−2) and current density (210.58 mA m−2) at the same concentration. Phytotoxicity tests using Lactuca sativa revealed reduced toxic effects after treatment under all conditions, with IC-treated effluents showing less inhibitory potential. The contrasting performance of the dyes treatment was attributed to their molecular structure and charge, influencing biosorption, electrochemical reduction, and microbial interactions. Microbial community analysis showed a dominance of electroactive and dye-degrading genera such as Rhodopseudomonas (46%), Comamonadaceae (18%) and Geobacteraceae (12%), all from the Proteobacteria phylum (62%), indicating an adapted biofilm in the MEA-anode environment. These findings support the potential of MFCs as a sustainable solution for energy recovery and treatment of dye-laden effluents.