Using dual chamber microbial fuel cells for coupled microplastic biodegradation and bioelectricity production: assessing the effect of substrate

Use of plastics has increased manifold over the last 50 years. Regrettably, their fragmentation into microplastics (MPs) (≤ 5 mm) created environmental and human health concerns. Traditional methods of MPs removal are limited by high energy requirements, high costs, and the use of chemical reagents. Microbial fuel cells (MFCs) provide a sustainable solution for treating wastewater containing MPs while simultaneously generating bioelectricity. This study investigated the potential of a microbial consortium in an MFC setup to remediate polyethylene terephthalate microplastics (PET-MPs) from a synthetic wastewater while generating electricity. Electrochemical process, substrate functionality (i.e., glucose and acetate), and microplastic degradation were tracked. Biodegradation effectiveness was evaluated using microscopic observations, microbial growth, and CO 2 release. The results indicated 21.4% ± 2% biodegradation of PET-MPs, with a maximum CO 2 release of 450 ± 173.9 ppm. Scanning electron microscopy and Fourier transform spectroscopy validated the result, showing structural impairment and disruption of the MP ester functions. Acetate increased degradation by 32% ± 2%, whereas glucose increased it marginally by 22% ± 2%. Maximum power density with acetate was 8.58 mW/m², significantly higher than that generated with PET-MPs alone (0.343 mW/m²; p < 0.05), and more than 25% COD reduction in MFCs demonstrated the potential of the systems for wastewater treatment. This work corroborates the feasibility of applying microbial fuel cells as a green technology solution for microplastic alleviation by examining microplastic degradation processes, substrate applications for degradation effectiveness, and their superiority over conventional removal methods.