Researchers have developed a microbial fuel cell that can simultaneously break down a harmful organic colour dye in synthetic wastewater while generating power, making it potentially useful for treating dye-contaminated industrial wastewater1.
Organic colour dyes are widely used in textile, paper and colour industries, which discharge such dyes into bodies of water, blocking sunlight and reducing oxygen production and thus inhibiting aquatic life. Existing techniques for treating industrial wastewater are expensive and tedious.
Scientists from the Indian Institute of Technology in Guwahati, India, invented the microbial fuel cell using a specific strain of photosynthetic cyanobacteria and polymer-coated magnetic nanoparticles. They then tested its efficiency in degrading an organic colour dye that is widely used in textile and paper industries.
The fuel cell degraded 89% of the dye and decolourised 65% of the dye-contaminated synthetic wastewater. The cell also produced electricity, generating current density that is higher than other bacteria-based fuel cells. The polymer-coated nanoparticles helped form a biofilm of cyanobacteria. Even in low light, the film-forming bacteria carried out photosynthesis, which created a flow of electrons between the cell’s electrodes, generating a current.
The bacteria also secreted reactive oxygen species that helped degrade the dye. Dye degradation formed mostly organic compounds that also contributed to current generation. Since the fuel cell could degrade a colour dye and decolourise wastewater, it can help increase light penetration and photosynthesis in an aquatic habitat.