Unlocking the potential of depleted dry batteries: A dual-purpose approach for waste mitigation and sustainable energy production

Electronic-waste (e-waste) poses a serious environmental challenge due to the increasing consumption and disposal of electronic devices. In the present work a novel method is proposed to repurpose e-waste and biowaste into a single-chamber and mediator-less microbial fuel cells using dead, non-rechargeable D-type dry batteries. The carbonaceous material inside the dry batteries was replaced with kitchen waste sludge, which served as the substrate. The outer zinc casing was also reused as the anode and the carbon rod as the cathode. Treating the kitchen waste sludge with dilute nitric acid improved the performance of the microbial fuel cells by enhancing the biodegradability and conductivity of the substrate. The untreated microbial fuel cells produced a maximum power density of 15.0 mW/kg at a maximum current density of 50.0 mA/kg, while the treated microbial fuel cells achieved 67.0 mW/kg at 178.0 mA/kg. The main mechanism behind the working of the device is the combined action of galvanic and microbial processes, which synergistically generate electricity from ewaste and bio-waste. Moreover, when four treated microbial fuel cells were connected in series, a high open circuit voltage of 3.3 V was achieved. These microbial fuel cells stand out as eco-conscious and lightweight alternatives to conventional dry batteries, presenting an environmentally sustainable solution for waste management and clean energy production.